tag:blogger.com,1999:blog-65740008396394336622024-03-17T22:04:05.510-05:00Equatorial MinnesotaMinnesota paleontology and geology, National Park Service paleontology, the Mesozoic, and occasional distractionsJustin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.comBlogger416125tag:blogger.com,1999:blog-6574000839639433662.post-89186682444524401012024-02-26T22:11:00.000-06:002024-02-26T22:11:41.132-06:00Stromatolites in situ<p>
A few weeks ago, during the elongated-dry-autumn-with-long-nights that has
been substituted for winter in these parts this year, I visited a stromatolite patch in
the Prairie du Chien Group and took the usual digital heap of photographs. The
photos aren't quite as sharp as I would have liked, but they show a variety of
aspects of stromatolites both up close and in situ, unlike the usual circumstances
of getting only one of those two properties.</p>
<p>First off, here's a general idea of what we're dealing with:</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2GLxgOrRFwuUrbbbTIvURv2aVQBjkRCUz6PJgDx25BIANfAsoA4V4GyOvDaAn4JfncaJYS-IwND7WZgl2ofy5g3KOqcJK89xc_aoAfkNsCaFcnd65yfTXZ6ClW-NBKIA4w2epaOsycPOD1Zh-iYa05PvmD1iC19e5phdRBZGNzm0T9bhSGjCohon5CK3v/s4117/columns.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2575" data-original-width="4117" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2GLxgOrRFwuUrbbbTIvURv2aVQBjkRCUz6PJgDx25BIANfAsoA4V4GyOvDaAn4JfncaJYS-IwND7WZgl2ofy5g3KOqcJK89xc_aoAfkNsCaFcnd65yfTXZ6ClW-NBKIA4w2epaOsycPOD1Zh-iYa05PvmD1iC19e5phdRBZGNzm0T9bhSGjCohon5CK3v/w400-h250/columns.jpg" width="400" /></a>
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Click to embiggen, as usual; the thing about stromatolites is sometimes
they're more apparent at a distance, and sometime they're more apparent
when your nose is practically on them. In this photo, there are columns
a couple of centimeters across in the lower part, leading to a small
shelf with a knobbly surface representing the tops of said columns,
followed by an interval of more obscure growth.<br />
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<p>
The prolific interval was up to about three quarters of a meter thick, with some significant variation, microbial
mounds not being big on standardization. Within this interval it was possible to
see where a mound's growth had been cut off, or changes between narrow columns
and broader stacks.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEio9guKqb4fUyt5-11UcpoQo4Pa6AWMigXDERf1jpioOFCFa0PmWXO1dXg42QARTdn7nBwTK7kNc5cy3r10pllI8amUS5lInREjSLs2ZIonsU429aUWvA6tXqjrtDYeBQWXtjpdNE2KqWg2PlLXSscY8qrRUOx3jsv__MlOzRi1OHxg8U0sY-CNQzcNRnof/s3991/constrained.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2099" data-original-width="3991" height="210" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEio9guKqb4fUyt5-11UcpoQo4Pa6AWMigXDERf1jpioOFCFa0PmWXO1dXg42QARTdn7nBwTK7kNc5cy3r10pllI8amUS5lInREjSLs2ZIonsU429aUWvA6tXqjrtDYeBQWXtjpdNE2KqWg2PlLXSscY8qrRUOx3jsv__MlOzRi1OHxg8U0sY-CNQzcNRnof/w400-h210/constrained.jpg" width="400" /></a>
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Here we have a broad mound of numerous coalesced small centers that is
cut off starkly about two-thirds of the way up the photo.<br />
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<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheZyVmobqX2VuWKSrffsKwdm7_kAIR_PPb1bZN9CSh8tsN-hE5_yu08eqENG11mKL8bXoeePPc5t5Kt-bSuuTHSxKkU9HzQzM45iu6s4-tGDCJf748G9XHTLR5fbYyzru4v4BNbqX3vKWY78EQjhNsK2QghvVAlP7IvaqUWIa5uYeG6FLFzPx2ROupJU3a/s3984/intervals.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2316" data-original-width="3984" height="233" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheZyVmobqX2VuWKSrffsKwdm7_kAIR_PPb1bZN9CSh8tsN-hE5_yu08eqENG11mKL8bXoeePPc5t5Kt-bSuuTHSxKkU9HzQzM45iu6s4-tGDCJf748G9XHTLR5fbYyzru4v4BNbqX3vKWY78EQjhNsK2QghvVAlP7IvaqUWIa5uYeG6FLFzPx2ROupJU3a/w400-h233/intervals.jpg" width="400" /></a>
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Another example where there appears to be discontinuity between the
growth lower in the photo and that in the upper part.<br />
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<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTreKNNxvoTqiyfpRCEJbP2_oKqWB3BE1JVPupDm051cz7rLBYbf1ZnuKn2o1s5TrBLXWCEg4jKA-kxwDkSMh4DptIv5qV-BPNjtu_EdxB2MT8ukGEWO4Lk-OSGFvjPT_YoESZ3Oh9fkk6mJiekGJV5y9wBeXPkdiKseT1SegHOLee2k2L-A-wh-y0MTEU/s4049/broad_to_narrow_better.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="4049" data-original-width="3019" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTreKNNxvoTqiyfpRCEJbP2_oKqWB3BE1JVPupDm051cz7rLBYbf1ZnuKn2o1s5TrBLXWCEg4jKA-kxwDkSMh4DptIv5qV-BPNjtu_EdxB2MT8ukGEWO4Lk-OSGFvjPT_YoESZ3Oh9fkk6mJiekGJV5y9wBeXPkdiKseT1SegHOLee2k2L-A-wh-y0MTEU/w299-h400/broad_to_narrow_better.jpg" width="299" /></a>
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This tall mound is fairly broad at the base, then goes into narrower
columns, then appears to show column consolidation near the top.<br />
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<p></p>
<p>
Part of why the photos may have lacked some clarity is the weathering of the
surfaces (and the bright light). The stromatolites had a sort of artistic
appearance in places, a bit like fingerprints in rock. I could see paintings
of these done with heavy strokes to emphasize the tactile appearance of
weathering layers.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidNEDt7sPQ5rEJnoP9PKDvkzyQqsJA0Jdum6RKC2CoifPur0evy0wGrRQ2g5Zx019weK6RSk_4NCP3_kUSjaPEo0wQtKs1Lu6AHVarTPAbX3yoR6fGj7_WhAPuCiIVz1EosVqnOv3Wd7JMdigEvycROJjTZJFBQJdaxNuB7CJbLD0ZLERhZBTlYRSOOc9n/s3522/the_persistence_of_stromatolites.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3016" data-original-width="3522" height="343" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidNEDt7sPQ5rEJnoP9PKDvkzyQqsJA0Jdum6RKC2CoifPur0evy0wGrRQ2g5Zx019weK6RSk_4NCP3_kUSjaPEo0wQtKs1Lu6AHVarTPAbX3yoR6fGj7_WhAPuCiIVz1EosVqnOv3Wd7JMdigEvycROJjTZJFBQJdaxNuB7CJbLD0ZLERhZBTlYRSOOc9n/w400-h343/the_persistence_of_stromatolites.jpg" width="400" /></a>
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There's a certain melted quality to this exposure.<br />
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<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiS0vP3jy5On-P-5v4WeRWqucnOU3i04YwbuasCyj108ET2c5M1TL1AiYdXlQbhP20UCvYy3YjhlOjqKpbgDgjc4kHWnezD0ChLc57NaLKUStMxtd7agXN6pBAxANaMb1N7a9fxajsJ8maSRPzA7S052DyezjuNcd07M1LRiBGtNvvkptU5KJgnsieGLApI/s3392/disrupted.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1718" data-original-width="3392" height="203" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiS0vP3jy5On-P-5v4WeRWqucnOU3i04YwbuasCyj108ET2c5M1TL1AiYdXlQbhP20UCvYy3YjhlOjqKpbgDgjc4kHWnezD0ChLc57NaLKUStMxtd7agXN6pBAxANaMb1N7a9fxajsJ8maSRPzA7S052DyezjuNcd07M1LRiBGtNvvkptU5KJgnsieGLApI/w400-h203/disrupted.jpg" width="400" /></a>
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I'm not sure what happened here, but this one looks like it's breaking
up (and there seems to be a big rounded pebble in the upper left).<br />
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<p></p>
<p>
Another interesting feature was the occasional exposure of the top surface
of a stromatolitic interval. Given the preponderance of smallish columns, it
should not come as a surprise that such surfaces are knobbly.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiE-lieQgpwDvNGgTvTjW05YxbXFpHnr-MCId9_v0VlmCqrTKdEshK_8JJ0AbmAu2UXt0oYCash43KAS4gRdAWo-D4Ea9hRATBmsr2_iucgtkfs50YybGQfiE5XixcUfAG487_wUVIKxXPm8zXp-9y3Z8h67lGGOFXNB85Td58qyjZgbLwlPT5H0iTJn6Ul/s3931/top_surface.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2911" data-original-width="3931" height="296" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiE-lieQgpwDvNGgTvTjW05YxbXFpHnr-MCId9_v0VlmCqrTKdEshK_8JJ0AbmAu2UXt0oYCash43KAS4gRdAWo-D4Ea9hRATBmsr2_iucgtkfs50YybGQfiE5XixcUfAG487_wUVIKxXPm8zXp-9y3Z8h67lGGOFXNB85Td58qyjZgbLwlPT5H0iTJn6Ul/w400-h296/top_surface.jpg" width="400" /></a>
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A close look will reveal the more or less concentric layers of
individual columns that have been truncated by weathering.<br />
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<p>
Finally, here's a surface showing columns that apparently grew out laterally.
We usually think of the original microbial colonies growing vertically, to reach the light, but again microbial mounds aren't big on standardization, and will grow as conditions influence them. (Or maybe this mound was simply knocked over at some point; unfortunately, we're missing most of it.)
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXlbFgIcI2880P5TybISSx9xoHMHxcXnVW61c-FLp2FccDqu_0d4btNOuVZnSxSkiOTUTWxdWDqnSDaphGk-YDCfFdT1bXfXC1snWegSnW7Da4K9zZlXpEfnapNCI3h2Ewjy7nxpSvX1KP3R2CjJU53KoY4KomUO-g8hMDDQgzzhcR1eRsOv1Ptdxe0J2_/s3056/on_the_side.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3056" data-original-width="2455" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXlbFgIcI2880P5TybISSx9xoHMHxcXnVW61c-FLp2FccDqu_0d4btNOuVZnSxSkiOTUTWxdWDqnSDaphGk-YDCfFdT1bXfXC1snWegSnW7Da4K9zZlXpEfnapNCI3h2Ewjy7nxpSvX1KP3R2CjJU53KoY4KomUO-g8hMDDQgzzhcR1eRsOv1Ptdxe0J2_/w321-h400/on_the_side.jpg" width="321" /></a>
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Preservation is different in this one as well, with layers still being
evident but expressed less colorfully. <br />
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<p></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com2tag:blogger.com,1999:blog-6574000839639433662.post-30083520395670313832024-02-11T19:27:00.000-06:002024-02-11T19:27:09.340-06:00Finding waterfalls<p>
A couple of months back, a friend pointed out a news items covering a slot
canyon in Crosby Farm Park, so we decided to see if we could find it. We were
successful in locating what's also called Homer's Odyssey (must be a pun based on
the proximity to Homer Street), and it turned out to be one of the
most unusual natural features of the Twin Cities. It's certainly worth a visit
the next time you're in the park, although I can imagine it could be difficult to access during a year when it rains more than once every three
months or so.
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUQQpG8i7zguozUvGhsV5O2k2dE0yxe2EKasPSGJRh3zEUPDC6iMR6djJvqkrklOPmxoKZME68V6NV71JTzqAEt_QpQm4Z0RW5j2HvyzKyC2nvYfBDyY57tc_KWwaDkr5SjsoDuuGOueB9tjirt8_iZY5NpMxv1gbnq5TnkbcnwhEEmrgnRQpXg4kzS1Oz/s4160/IMG_20231118_132714122_HDR.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUQQpG8i7zguozUvGhsV5O2k2dE0yxe2EKasPSGJRh3zEUPDC6iMR6djJvqkrklOPmxoKZME68V6NV71JTzqAEt_QpQm4Z0RW5j2HvyzKyC2nvYfBDyY57tc_KWwaDkr5SjsoDuuGOueB9tjirt8_iZY5NpMxv1gbnq5TnkbcnwhEEmrgnRQpXg4kzS1Oz/w400-h300/IMG_20231118_132714122_HDR.jpg" width="400" /></a>
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Approaching the entrance.<br />
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<p></p>
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Looking back through the slot.<br />
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<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXzqzt6jKjLXKYJgLACbpzbPzYpSt3Rkp0BuMSqVvg0DpkKpmFhqqG32-vD_u4uTe_HjKMHvmiiy03ByEe6Hujbevb0QmM9KmZcorQLj83Wn__wu4UkPlDZO6OG5fBf8lvOckzfRFGJZD90E8OfSoUO22hvm_uppGCIaCSQMfNZVfM6T7H8yTmHxlvfIX-/s4160/IMG_20231118_132848837_HDR.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="4160" data-original-width="3120" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXzqzt6jKjLXKYJgLACbpzbPzYpSt3Rkp0BuMSqVvg0DpkKpmFhqqG32-vD_u4uTe_HjKMHvmiiy03ByEe6Hujbevb0QmM9KmZcorQLj83Wn__wu4UkPlDZO6OG5fBf8lvOckzfRFGJZD90E8OfSoUO22hvm_uppGCIaCSQMfNZVfM6T7H8yTmHxlvfIX-/w300-h400/IMG_20231118_132848837_HDR.jpg" width="300" /></a>
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Inside the feature, which is kind of like a tall roughly cylindrical void.<br />
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<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv4VW0lDBJj2cnS9yvOOoGjFQVk1PGAn9eFZlntUWA2zTUD7zXcBCZDYO93MnjH_cKBQoH9m9ZjFKOh9qVVTfC6sdmW8NzSxPb7KAx6dgb-pC-RUo0wVrjOebN3NuPalO5_8-fZOZzxLuzNVAT_2SuLQmrO8sJFkiWAPOcM7JIdwuqWxz2Tdngo_0nZRBV/s4160/IMG_20231118_132947836_HDR.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv4VW0lDBJj2cnS9yvOOoGjFQVk1PGAn9eFZlntUWA2zTUD7zXcBCZDYO93MnjH_cKBQoH9m9ZjFKOh9qVVTfC6sdmW8NzSxPb7KAx6dgb-pC-RUo0wVrjOebN3NuPalO5_8-fZOZzxLuzNVAT_2SuLQmrO8sJFkiWAPOcM7JIdwuqWxz2Tdngo_0nZRBV/w400-h300/IMG_20231118_132947836_HDR.jpg" width="400" /></a>
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Looking up at the top.<br />
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<p>
The canyon is almost like someone took a knife and cut straight down. Granted,
it's not as if fresh St. Peter Sandstone shows much in the way of resistance
to erosion, but I do wonder if there was a pre-existing weakness that focused
this erosion so narrowly. Maybe there were voids in the sandstone or something similar?<br /></p>
<p>
Active waterfalls, waterfalls reduced to a trickle, and former waterfalls
<a href="https://www.minnesotahistory.org/post/the-cascades-of-minneapolis-and-st-paul" rel="nofollow" target="_blank">are scattered all over the Twin Cities metro</a>. Some former falls, like the
<a href="https://equatorialminnesota.blogspot.com/2016/11/cottage-grove-ravine-regional-park.html" rel="nofollow" target="_blank">one in Cottage Grove Ravine Park</a>
or the abandoned falls northeast of Minnehaha Falls, have been high and dry
for a long time due to the loss of their water source in the mists of
time, but many have lost their flow due to drainage control measures in the
past 150 years or so. Some could be reanimated with different priorities,
while others have been buried or destroyed.
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_O-s9I59XrLPZmH4d7yOxUCW12pzfrYYFkscKWPtNxvP3RIewfQOSp2dIcarsgu78RkgXLEbjPSz5Nbgw-0kr-DynWN2rxh4O8hgkzsRM1YwGPT9loRtmwHOu8AmF-BKWr4I-x1m6PFOBs4C7JYhrl5q6cdpL2J-9Q6C1YJmnmGQxHF7m45db_NY6NLCi/s4160/IMG_20221009_150441625_HDR.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_O-s9I59XrLPZmH4d7yOxUCW12pzfrYYFkscKWPtNxvP3RIewfQOSp2dIcarsgu78RkgXLEbjPSz5Nbgw-0kr-DynWN2rxh4O8hgkzsRM1YwGPT9loRtmwHOu8AmF-BKWr4I-x1m6PFOBs4C7JYhrl5q6cdpL2J-9Q6C1YJmnmGQxHF7m45db_NY6NLCi/w400-h300/IMG_20221009_150441625_HDR.jpg" width="400" /></a>
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<td class="tr-caption" style="text-align: center;">
And even the best of them sometimes get caught short in droughts, as
Minnehaha Falls shows in early October 2022.<br />
</td>
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</tbody>
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<p>
Even beyond the named falls, there are many small-scale unnamed or obscure features. If
you're looking to find some for yourself, you can often guess general areas
to look from topo maps: look for valleys crossing steep contours. That's a telltale sign that a creek once crossed a bluff, or something similar. Or, if you'd
rather try immediate adventure, get on one of the gorge trails (e.g., the
<a href="https://en.wikipedia.org/wiki/Winchell_Trail" rel="nofollow" target="_blank">Winchell Trail</a>
in Minneapolis or the unnamed goat path equivalents on the St. Paul side) and
just keep your eyes open; they're there.
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz_d-gBs0HlvQFV_rET8Ag7imb8pSGaqH2uH0Nr06cXG9lMxzVlQqDCP6d8he8r0lMICXeDmJcOjcukWgRd2c1MhugT4pdZr4ikzrtBym4VtNOKMb8yKTdBO6CtCggIUeY-q0N8koHeJFipGlKvXPqZ0-9VLm8f4IfTeFfyhf5-nkZ5S2tPvWBHCOjcI73/s4160/IMG_20231124_140522919_HDR.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz_d-gBs0HlvQFV_rET8Ag7imb8pSGaqH2uH0Nr06cXG9lMxzVlQqDCP6d8he8r0lMICXeDmJcOjcukWgRd2c1MhugT4pdZr4ikzrtBym4VtNOKMb8yKTdBO6CtCggIUeY-q0N8koHeJFipGlKvXPqZ0-9VLm8f4IfTeFfyhf5-nkZ5S2tPvWBHCOjcI73/w400-h300/IMG_20231124_140522919_HDR.jpg" width="400" /></a>
</td>
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<td class="tr-caption" style="text-align: center;">
The falls in the Grotto, exiting the University of St. Thomas.<br />
</td>
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</tbody>
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<p></p>
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<tbody>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz73_e9MzntfQbebcdtVPviOh34uRSfiz4XThMgoWzgut8kNccMB_ZC2UfWfQHVlN1ddNdRFfA52oHr_jS95bEHbhMhctEheX-u2HhSTJEZzLM5IIsWeLVt0_OzWcNvp6hev6ViKKRLo0AoRe5lBp8k8n-e0dQFkUdTdUJQAxmRKUef2Y9LeX5tYRRCX77/s4160/IMG_20231118_153437827.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz73_e9MzntfQbebcdtVPviOh34uRSfiz4XThMgoWzgut8kNccMB_ZC2UfWfQHVlN1ddNdRFfA52oHr_jS95bEHbhMhctEheX-u2HhSTJEZzLM5IIsWeLVt0_OzWcNvp6hev6ViKKRLo0AoRe5lBp8k8n-e0dQFkUdTdUJQAxmRKUef2Y9LeX5tYRRCX77/w400-h300/IMG_20231118_153437827.jpg" width="400" /></a>
</td>
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<tr>
<td class="tr-caption" style="text-align: center;">
This is on the Minneapolis side, just across from E 36th Street. I've
never heard that this one had a name, so it may well not have been doing
more than a trickle when Minneapolis was developed, but it would have
been substantial at one time.<br />
</td>
</tr>
</tbody>
</table>
<p>
Another area is south of Minnehaha Park, in the Coldwater Spring/dog
park area. There is a secluded active waterfall southeast of Coldwater that has cut a modest slot in the St. Peter; again I'm
not sure if it has a widely circulating name. Novelty Falls on the bluffs
north of the dog park is very difficult to notice when the falls aren't falling;
observation of the bluffs suggests there are several other places that may get
mini-falls if there is a lot of rain or meltwater. Marks of water erosion at the top of the bluffs and water-worn hollows at the base will show you where flow has occurred.<br /></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTMy_F3hArp8j3KGcSIywuOGIuvPzdmeSqPUFukJ61u1KIWjwVKz5r5cQ18VzWYTJzcS3wNGpaxEVQ66lzVb5lwRjNNx32IpY_FQHEH8YEdsbh9dgTXfetODPEskePDJukqHjyQ4ywMPXd1MQaED9k_lbL-k0Xy4uCu-eH9ummUXV3zCdpR4c7315C4UAM/s4608/IMG_6620.JPG" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3456" data-original-width="4608" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTMy_F3hArp8j3KGcSIywuOGIuvPzdmeSqPUFukJ61u1KIWjwVKz5r5cQ18VzWYTJzcS3wNGpaxEVQ66lzVb5lwRjNNx32IpY_FQHEH8YEdsbh9dgTXfetODPEskePDJukqHjyQ4ywMPXd1MQaED9k_lbL-k0Xy4uCu-eH9ummUXV3zCdpR4c7315C4UAM/w400-h300/IMG_6620.JPG" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
A close view, low and up into the chute of the Coldwater waterfall. It's
rather more impressive in person, as it tends to photograph poorly due to
the confines of the site and the limited foot space. (Note that this
area below the bluff has a tendency to become a respectable swamp
following anything stronger than a light rain.)<br />
</td>
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</tbody>
</table>
<p></p>
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<tbody>
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<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWcILZNL_301W9MnMRHRiMGQIwsW3JdJBdlXKCAaLBOK-QgKBpEdSnKsbNVoZByRD8ZpK0AV1N1aUb2eXnuyw309MjrrTuTHCoy84HauhWEt9WEFVmhEYMybQo6574FHg4hnCJQP4IGkwcuStSxF2MYKzWsUDBRu6GgIIcpvHHE1P16CdKEw0cTE6811fM/s4160/IMG_20231202_140810493.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWcILZNL_301W9MnMRHRiMGQIwsW3JdJBdlXKCAaLBOK-QgKBpEdSnKsbNVoZByRD8ZpK0AV1N1aUb2eXnuyw309MjrrTuTHCoy84HauhWEt9WEFVmhEYMybQo6574FHg4hnCJQP4IGkwcuStSxF2MYKzWsUDBRu6GgIIcpvHHE1P16CdKEw0cTE6811fM/w400-h300/IMG_20231202_140810493.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Novelty Falls itself wasn't running in November, but these bluffs are
very interesting!<br />
</td>
</tr>
</tbody>
</table>
<p>
They are also present on the south side of the Mississippi; for example, the
Brickyard trail in Lilydale Regional Park passes right by one:
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
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<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVNFawBB4JujKcRwIEyB5HYJFgKIWN4xlS4w0vNiXBPn51OOMwPuebSrTUrQHhRoxJHVwJZzo2L6SpNoLKo13TJAMrcbmxWL8Wj6AdF5zoZoqP5O_W375gKkk6GhXwK_X0D3yWgKtbOfz68vWO6RHNuxV9RPybGRMaUqSQgx20UmEOkmOhH3wP5hJpqE7W/s4160/IMG_20240106_154600148.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3120" data-original-width="4160" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVNFawBB4JujKcRwIEyB5HYJFgKIWN4xlS4w0vNiXBPn51OOMwPuebSrTUrQHhRoxJHVwJZzo2L6SpNoLKo13TJAMrcbmxWL8Wj6AdF5zoZoqP5O_W375gKkk6GhXwK_X0D3yWgKtbOfz68vWO6RHNuxV9RPybGRMaUqSQgx20UmEOkmOhH3wP5hJpqE7W/w400-h300/IMG_20240106_154600148.jpg" width="400" /></a>
</td>
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<td class="tr-caption" style="text-align: center;">
Here pictured during one of the few days this "winter" when there was
snow on the ground.<br />
</td>
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</tbody>
</table>
<p>(And yes, I am well aware that this blog has never covered the
Brickyard...)</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-45358910018397111622024-02-01T21:10:00.001-06:002024-02-01T21:11:51.406-06:00Your Friends The Titanosaurs: Gandititan cavocaudatus?<p>Here we are, already through January of 2024, and clearly we are not starting out like 2023, where the entire month had nary a new dinosaur. Today's entrant was the third of five announced in January 2024 (a couple of weeks ago, actually). You may notice the question mark in the post title; although described as a basal titanosaurian, <i>Gandititan cavocaudatus</i> fits a certain "type" of sauropod (<a href="https://equatorialminnesota.blogspot.com/2021/04/your-friends-titanosaurs-35-part-time-titanosaurs.html" rel="nofollow" target="_blank">mid-Cretaceous East Asian titanosauriform</a>) that delights in phylogenetic instability. This to me is a subtle signal that something is going on we don't understand yet, so I'd best hedge my bets. So, maybe it's a titanosaur, maybe it isn't, but at any rate it's worth an introduction.<span></span></p><a name='more'></a><p></p><p><u>Genus and Species</u>: <i>Gandititan cavocaudatus</i>. The genus name is multilayered. "Gan" refers to Ganzhou City and "di" "is the Chinese pinyin word for the Earth and is also the first syllable of 'dizhi', meaning 'geology'", with the whole intended to honor "geologic work in Ganzhou City". "Titan", of course, means "titan", and goes with sauropod theme naming. The species name is a combination of the Latin words for "cavity" and "tail", referring to the "complicated pattern of pleurocoels and <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow" target="_blank">neural arch</a> laminae seen in the <a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow" target="_blank">anterior</a> caudal vertebrae". The intended translation is "cavity tailed" (Han et al. 2024).</p><p><u>Citation</u>: Han, F., L. Yang, F. Lou, C. Sullivan, X. Xu, W. Qiu, H. Liu, J. Yu, R.
Wu, Y. Ke, M. Xu, J. Hu, and P. Lu. 2024. A new titanosaurian sauropod, <i>Gandititan cavocaudatus</i> gen. et sp. nov., from the Late Cretaceous of southern China, Journal of Systematic Palaeontology 22(1): 2293038. doi: <a href="https://doi.org/10.1080/14772019.2023.2293038" rel="nofollow" target="_blank">https://doi.org/10.1080/14772019.2023.2293038</a>. </p><p></p><p><u>Geography and Stratigraphy</u>: The type and only known specimen of <i>G. cavocaudatus</i> comes from "100 m north of Shiziyan Road, Datankeng, Ganxian District, Ganzhou City, Jiangxi Province, China", in rocks of the lower Upper Cretaceous Zhoutian Formation (Han et al. 2024).<br /></p><p></p><p><u>Holotype</u>: JXGM-F-V1 (Jiangxi Geological Museum, Jiangxi), which consists mostly of vertebrae: six articulated middle–posterior cervicals with fused ribs, two articulated dorsals, two partial dorsal ribs, and six articulated sacrals and 17 caudals plus the right ilium and chunks of the corresponding pubis and ischium (Han et al. 2024).<br /></p><p>The type specimen was found as, essentially, the sacral–caudal segment and the cervical segment, in close association, preserved as aesthetically pleasing off-white bones in a much darker matrix. Enough was present for Han et al. to make an informed estimate of 14 m (46 ft) for the individual's length, so we're dealing with a roughly medium-sized titanosaur or titanosaur relative. The neural arches are fused (Han et al. 2024), so this is probably reasonably close to adult size as well.</p><p>The preserved cervicals come from around the middle to base of the neck, and are somewhat elongate. The neural spines are somewhat triangular in profile, becoming taller up-down and shorter fore-aft going back, as well as angling more anteriorly. The spines are also bifurcated (split longitudinally), which is uncommon for titanosaurs. The cervical ribs are fused to their vertebrae and not unusually long. The two dorsals are not in sequence with either the cervical or sacral–caudal segment, but represent something in the middle or posterior dorsal sequence. They are only partially preserved. The left side of the sacrum is eroded, and the right side is fused to the ilium. The neural spines of the sacrals are fused into a continuous "platform". Unlike traditional titanosaurs, the caudals are opisthocoelous rather than procoelous, and the neural arches are close to the same length as their centra rather than distinctly cheated forward. The caudals look rather chunky and squared-off. Unusually, the anterior caudal neural spines are also bifurcated (Han et al. 2024).</p><p>Han et al. include a comparison of <i>G. cavocaudatus</i> to other titanosauriforms from the Cretaceous of East Asia, the kind of thing that would have been nice in some other recent titanosaur publications. (<a href="https://equatorialminnesota.blogspot.com/2021/03/your-friends-titanosaurs-34-yesterday.html" rel="nofollow" target="_blank"><i>Qinlingosaurus luonanensis</i></a> is overlooked, but to be fair, everyone overlooks it.) They also include a new phylogeny, which finds <i>G. cavocaudatus</i> to be closest to <a href="https://equatorialminnesota.blogspot.com/2020/02/your-friends-titanosaurs-part-215-abdarainurus.html" rel="nofollow" target="_blank"><i>Abdarainurus barsboldi</i></a> in a basal titanosaur clade also including <a href="https://equatorialminnesota.blogspot.com/2018/11/your-friends-titanosaurs-6-austroposeidon-balochistan-baotianmansaurus.html" rel="nofollow" target="_blank"><i>Baotianmansaurus henanensis</i></a>, <i><a href="https://equatorialminnesota.blogspot.com/2019/03/your-friends-titanosaurs-10-diamantinasaurus-dongyangosaurus-dreadnoughtus.html" rel="nofollow" target="_blank">Dongyangosaurus sinensis</a></i>, <a href="https://equatorialminnesota.blogspot.com/2021/04/your-friends-titanosaurs-35-part-time-titanosaurs.html" rel="nofollow" target="_blank"><i>Huabeisaurus allocotus</i></a>, and, strangely enough, <a href="https://equatorialminnesota.blogspot.com/2018/08/your-friends-titanosaurs-3-andesaurus-antarctosaurus-argentinosaurus.html" rel="nofollow" target="_blank"><i>Andesaurus delgadoi</i></a>. <a href="https://equatorialminnesota.blogspot.com/2023/04/the-face-of-diamantinasaurus.html" rel="nofollow" target="_blank">Diamantinasaurs</a> turn up just outside of Titanosauria, and a couple of recently featured names, <a href="https://equatorialminnesota.blogspot.com/2023/09/your-friends-titanosaurs-jiangxititan.html" rel="nofollow" target="_blank"><i>Jiangxititan ganzhouensis</i></a> and <i><a href="https://equatorialminnesota.blogspot.com/2023/02/your-friends-titanosaurs-chucarosaurus-ruixinia.html" rel="nofollow" target="_blank">Ruixinia zhangi</a></i>, are farther outside, which just goes to show the value of prudence when these darn things are playing coy.</p><p>References</p><p>Han, F., L. Yang, F. Lou, C. Sullivan, X. Xu, W. Qiu, H. Liu, J. Yu, R. Wu, Y. Ke, M. Xu, J. Hu, and P. Lu. 2024. A new titanosaurian sauropod, <i>Gandititan cavocaudatus</i> gen. et sp. nov., from the Late Cretaceous of southern China, Journal of Systematic Palaeontology 22(1): 2293038. doi: <a href="https://doi.org/10.1080/14772019.2023.2293038" rel="nofollow" target="_blank">https://doi.org/10.1080/14772019.2023.2293038</a>. <br /></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-40667553870078582072024-01-14T10:50:00.001-06:002024-01-14T10:50:18.861-06:00Parks Stewardship Forum: National Park Service Paleontology<p>For the past year, my supervisor Vincent Santucci and I have been assisting the preparation of a group of articles on National Park Service paleontology for <a href="https://escholarship.org/uc/psf" rel="nofollow" target="_blank"><i>Parks Stewardship Forum</i></a>. We've assembled seventeen articles from various contributors on a variety of topics and parks, covering aspects of inventory, monitoring, research, and curation, from semitechnical to technical (the Florissant and John Day articles are the most technical, if you're concerned about that). Our issue has now gone live, and you can read and download each of the articles <a href="https://escholarship.org/uc/psf/40/1" rel="nofollow" target="_blank">here</a>. I hope you find something you like!<br /></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjt357Np-gHHIvPskkGEJBlj9cV3keveitFc7lYXvJPgQ0sZ5eJX84H5dyb2i5OEKIgx3z1ml8gxieA216AJkstiB7pTZAGQI9seWnvpvSWK9X6mfAW82_Nvbrf1X65UievPYSXutOED3rAi_7hqpsRrz3XtLJeeffYMJCWJ9hHELsLvXAubTpQshFaIgjZ/s1632/psf_cover.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1632" data-original-width="1238" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjt357Np-gHHIvPskkGEJBlj9cV3keveitFc7lYXvJPgQ0sZ5eJX84H5dyb2i5OEKIgx3z1ml8gxieA216AJkstiB7pTZAGQI9seWnvpvSWK9X6mfAW82_Nvbrf1X65UievPYSXutOED3rAi_7hqpsRrz3XtLJeeffYMJCWJ9hHELsLvXAubTpQshFaIgjZ/w304-h400/psf_cover.png" width="304" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The cover comes from one of my pet projects, the paleontology of George Washington Birthplace National Monument (for which I contributed <a href="https://escholarship.org/uc/item/7zn0h4zw" rel="nofollow" target="_blank">an article</a>).<br /></td></tr></tbody></table>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-57948644104184852152024-01-07T12:34:00.002-06:002024-01-07T12:34:41.526-06:00Cottage Grove cystoid<p>I recently paid a return visit to the site in Cottage Grove where I'd previously spotted <a href="https://equatorialminnesota.blogspot.com/2022/12/platteville-fossils-in-cottage-grove.html" rel="nofollow" target="_blank">a few blocks with brachiopods/etc.</a> of the typical Platteville persuasion. While there, a few true outcrops were visible under the snow-free conditions of the so-called winter of December 2023, confirming that the Platteville is indeed at the surface and not just present as lag or buried under a bad toupee of soil and glacial debris. More significant was one of the blocks. See if you can spot what drew my attention:</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9IXAMd-haD0uT6sMooqtw5gbrnWQUrkCWKof_Vjc2Tv3NlDiv6jRsjVtJjSV0qQA-DJt2KVYQ3yWRekwFzuUBYrKNSJt7zgOi3byZlRDxB9A5emWmP1icsuEGpESMXnJyoiw21Kbv-8B3TDLHeC-hcpsccpfs1saTCpJAadjv4cXcNvOoOlt_-4KSwoA1/s3160/cystoid_block_crop.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2801" data-original-width="3160" height="355" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9IXAMd-haD0uT6sMooqtw5gbrnWQUrkCWKof_Vjc2Tv3NlDiv6jRsjVtJjSV0qQA-DJt2KVYQ3yWRekwFzuUBYrKNSJt7zgOi3byZlRDxB9A5emWmP1icsuEGpESMXnJyoiw21Kbv-8B3TDLHeC-hcpsccpfs1saTCpJAadjv4cXcNvOoOlt_-4KSwoA1/w400-h355/cystoid_block_crop.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Any ideas?<br /></td></tr></tbody></table><p></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKF925iJZ47ZV7Ln-kG0xoUhhERpKJbSyrhGXb4_A4RQ0xwUzs-dYia3LFkR0J27z2mZDSFfIBv21GvEdW3bAb7GKo3WMANLm8KarGYc3RWHqNNfNtgUndx19aSmEzuSeWbmhfkI3b7WtDHq-NoTBSiQ73b931BK2KmUBDl2qVt-Hox5EZLn2GOyFT0vuT/s3021/cystoid_block_closeup.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2413" data-original-width="3021" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKF925iJZ47ZV7Ln-kG0xoUhhERpKJbSyrhGXb4_A4RQ0xwUzs-dYia3LFkR0J27z2mZDSFfIBv21GvEdW3bAb7GKo3WMANLm8KarGYc3RWHqNNfNtgUndx19aSmEzuSeWbmhfkI3b7WtDHq-NoTBSiQ73b931BK2KmUBDl2qVt-Hox5EZLn2GOyFT0vuT/w400-h320/cystoid_block_closeup.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">How about if we go in closer on the area of interest?<br /></td></tr></tbody></table><p></p><p>If you answered something along the lines of "the thing near the center that looks kind of like a truncated letter K", you've won! I snapped a couple of pictures thinking it might be echinoderm in origin and moved on. Later, upon reviewing the photos, the rectangular bit below it caught my eye; that <i>definitely</i> looked echinoderm. In fact, there is only one kind of thing it could belong to, as proclaimed by the chevron arrangement of slots on it surface. This is a plate from a <a href="https://equatorialminnesota.blogspot.com/2015/08/all-of-other-echinoderms.html" rel="nofollow" target="_blank">rhombiferan cystoid</a> bearing a pore rhomb in a pectinirhomb configuration. ("Of course!" you shout.) (Okay, so I looked up the anatomical terminology). Basically, the slots are vents for the animal's water circulation system.</p><p>This rock was obviously a good candidate for further study and photography, so I took some more photos with the hope of doing some taxonomy. Further inspection revealed a couple sharply ridged features similar to the "K", but more weathered.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgybRe7VdzWdTZUy9eAx4UCgaTwDLiArnSsggiP9IuStBEj-57PFLk_dSuVb8FKeI6aii6Vgw1OllU8zIEcYGJkYTMjNnvMGiZrA-QBzZADlGg05XUgCFSvuYq7xXAN0LCY7TLqrqGtIRfUhXOskeR8SV-DYbPE-1OHUF42s9rsZJ9w7xvEOe3i6lo6i7M9/s2051/other_possible_plates.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2051" data-original-width="2050" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgybRe7VdzWdTZUy9eAx4UCgaTwDLiArnSsggiP9IuStBEj-57PFLk_dSuVb8FKeI6aii6Vgw1OllU8zIEcYGJkYTMjNnvMGiZrA-QBzZADlGg05XUgCFSvuYq7xXAN0LCY7TLqrqGtIRfUhXOskeR8SV-DYbPE-1OHUF42s9rsZJ9w7xvEOe3i6lo6i7M9/w400-h400/other_possible_plates.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">There's a pretty well-developed one in the upper right, and one that is more poorly exposed near the left side. <br /></td></tr></tbody></table><p>When I first noticed the "K", I thought it might be ridges on a crinoid plate, but local crinoid plates don't usually have such sharp ridges. Instead, it turns out that there is a Platteville cystoid that does, <i>Coronocystis durandensis</i>. Coincidentally, this particular cystoid also has pore rhombs that are a good match for the pore rhomb plate on this rock (see photos in <a href="https://equatorialminnesota.blogspot.com/2023/09/fossils-of-upper-ordovician-platteville.html" rel="nofollow" target="_blank">Kolata 2021</a>).</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhACWmXDL69ZmckEB06fHc5i3SgEcnaMUDf-LUZdpQR3lGeHMCd6rNZPIFo9B3iQXoteSeElem8iF0V9QGEfLZLh39g23P0ypGpe5GTyhmtTPx9i1vrjmWv25OldBbnPKp-69zY5ahxAruoKWoQZpFWXdIoldBdXhOfQnplPEpn0C9BYUDt3H9JNt9fkCtt/s2558/cystoid_close_crop.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1907" data-original-width="2558" height="299" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhACWmXDL69ZmckEB06fHc5i3SgEcnaMUDf-LUZdpQR3lGeHMCd6rNZPIFo9B3iQXoteSeElem8iF0V9QGEfLZLh39g23P0ypGpe5GTyhmtTPx9i1vrjmWv25OldBbnPKp-69zY5ahxAruoKWoQZpFWXdIoldBdXhOfQnplPEpn0C9BYUDt3H9JNt9fkCtt/w400-h299/cystoid_close_crop.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Here close-up and with a tiny drip of water applied. There is also a gray rectangular ridge visible near the right border that I suspect to be another plate, but it's not as well-exposed.<br /></td></tr></tbody></table><p></p><p>I hesitate to make a firm identification from the available material, but it certainly appears that we have <i>Coronocystis</i> or something very similar. <i>Coronocystis</i> is interpreted as a stalked rhombiferan cystoid, unlike its free-thrashing cousin <i><a href="https://equatorialminnesota.blogspot.com/2023/12/release-robotic-pleurocystites.html" rel="nofollow" target="_blank">Pleurocystities</a></i> (which does pore rhombs differently and has softer ridges). I interpret the block as from the <a href="https://equatorialminnesota.blogspot.com/2014/01/divisions-of-platteville-formation.html" rel="nofollow" target="_blank">Mifflin Member</a> of the Platteville, but I suppose it could be higher. Whatever the exact identification at the genus or species level, this is clearly a rhombiferan cystoid, and the first I've ever seen in the field (and I'm pretty sure the first record from Cottage Grove). Plus, the several bits suggest a disarticulated but fairly associated specimen.<br /></p><p>References</p><p>Kolata, D. R. 2021. Fossils of the Upper Ordovician Platteville
Formation in the upper Midwest USA: an overview. Illinois State
Geological Survey, Prairie Research Institute, University of Illinois at
Urbana-Champaign, Champaign, Illinois. Bulletin 108.</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-8878946516830934732023-12-24T15:01:00.000-06:002023-12-24T15:01:00.498-06:00Your Friends The Titanosaurs: Bustingorrytitan shiva<p>In terms of dinosaurs, 2023 is going to go out like it <a href="https://equatorialminnesota.blogspot.com/2023/02/your-friends-titanosaurs-chucarosaurus-ruixinia.html" rel="nofollow" target="_blank">came in</a>: with a new plus-sized Huincul Formation titanosaur. This one has been delivered just in time for Christmas, although it's unlikely to fit under anyone's tree. Of
course, there have been some comments that it is not as big as has been
published, but regular readers will know
<a href="https://equatorialminnesota.blogspot.com/2014/09/on-this-occasion-of-receiving-new-giant.html" rel="nofollow" target="_blank">not to get too wrapped up</a>
in these things.
</p>
<span><a name='more'></a></span><p></p>
<p>
<u>Genus and Species</u>: <i>Bustingorrytitan shiva</i>. The genus name honors
the landowner Manuel Bustingorry, while the species name invokes the Hindu
deity Shiva, the Destroyer, an allusion to the faunal turnover at the
<a href="https://equatorialminnesota.blogspot.com/p/geologic-time.html" rel="nofollow" target="_blank">Cenomanian–Turonian</a> boundary that occurred not long after the late Cenomanian
time of <i>B. shiva</i> (Simón and Salgado 2023). I'm not quite sure how to
work the species, but obviously the genus translates roughly to "Manuel
Bustingorry's titan".
</p>
<p>
<u>Citation</u>: Simón, M. E., and L. Salgado. 2023.
<a href="https://app.pan.pl/article/item/app010862023.html" rel="nofollow" target="_blank">A new gigantic titanosaurian sauropod from the early Late Cretaceous of
Patagonia (Neuquén Province, Argentina)</a>. Acta Palaeontologica Polonica in press. doi:
<a href="https://doi.org/10.4202/app.01086.2023" rel="nofollow" target="_blank">https://doi.org/10.4202/app.01086.2023</a>.
</p>
<p>
<u>Geography and Stratigraphy</u>: The specimens come from the "Bustingorry
II" site northwest of Villa El Chocón in central Neuquén Province, central
western Argentina. Stratigraphically, we're in the late Cenomanian-age Huincul
Formation of the Neuquén Group, 60 m (200 ft) above the "La Antena" quarry
that produced fellow titanosaur
<a href="https://equatorialminnesota.blogspot.com/2019/02/your-friends-titanosaurs-9-campylodon-clasmodosaurus-choconsaurus-daxiatitan.html" rel="nofollow" target="_blank"><i>Choconsaurus baileywillisi</i></a>, near the base of the same formation (Simón and Salgado 2023).
</p>
<p>
<u>Holotype</u>: MMCH-Pv 59/1–40 (paleovertebrate collection, Museo Municipal
de Villa El Chocón "Ernesto Bachmann", Neuquén, Argentina), which is one where
various bones each get their own numbers within the group number 59. There's a
little bit of everything, including the right <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow" target="_blank">dentary</a>, a tooth, a middle
dorsal vertebra, four caudals, a couple of chevrons, both shoulder girdles
(scapulae, coracoids, and sternal plates), the left ilium and part of the
right, the right pubis, both humeri and ulnae, the right radius, all five
right metacarpals, the right femur, tibia, and fibula, the left fibula and
astragalus, three metatarsals, and three phalanges (Simón and Salgado 2023).
(The bias to the right side suggests to me that the carcass was on its right side.)</p><p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzVgUMwtM5DHIXEhkmhwybJeI0dz3YuYt4dUYd161vKnvarGheLms2r7JAF6_W1Ytiw-osYTKf66pTndzQBKGm8VN_m9NtttE6P5ySvPBWjQt3Z1sOrE06VRNFVP22y1DcCAJSlkpuf1Z4MJsUk0zxtQe86uq5V5Pn4r_pZ1ef9jGGvIsw75AHI9LsvAw2/s1179/bustingorrytitan_arm_shoulder.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1179" data-original-width="876" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzVgUMwtM5DHIXEhkmhwybJeI0dz3YuYt4dUYd161vKnvarGheLms2r7JAF6_W1Ytiw-osYTKf66pTndzQBKGm8VN_m9NtttE6P5ySvPBWjQt3Z1sOrE06VRNFVP22y1DcCAJSlkpuf1Z4MJsUk0zxtQe86uq5V5Pn4r_pZ1ef9jGGvIsw75AHI9LsvAw2/w298-h400/bustingorrytitan_arm_shoulder.jpg" width="298" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Figure 5 from Simón and Salgado (2023) (<a href="https://app.pan.pl/article/item/app010862023.html" rel="nofollow" target="_blank">which see for full caption</a>), illustrating the elements of the arm and pectoral girdle of <i>Bustingorrytitan shiva</i>. Scale bars are 200 mm (7.87 in). <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.</td></tr></tbody></table><br />The story of <i>B. shiva</i> appears to go back more than 20 years as the
shadowy informal name/typo "Sauropodus". A press release from 2001
<a href="https://reptilis.net/DML/2001Feb/msg00345.html" rel="nofollow" target="_blank">that was preserved</a>
by the Dinosaur Mailing List matches the formation, location, and lead
researcher, and the material is described as including "upper and lower limbs,
vertebrae, ribs and a piece of tooth." Apart from the ribs, this is basically
the holotype of <i>B. shiva</i> (and does not fit particularly well with any other named contender). The material also was
reported in an abstract I haven't seen (Simón 2001), and a thesis I haven't
seen (Simón 2011; you can find the abstract
<a href="https://catalogo.biblio.unc.edu.ar/Record/exactas.21495/Description" rel="nofollow" target="_blank">here</a>, though), so I cannot comment much on them. (I did, though, find Leonardo
Filippi's 2021
<a href="http://rdi.uncoma.edu.ar/handle/uncomaid/17165" rel="nofollow" target="_blank">doctoral thesis</a>
on Sierra Barrosa Formation titanosaurs while looking for it, in case you'd
like to see that.)
</p>
<p>
Not only is there an extensive (if limb- and girdle-dominated holotype), but
at least three other individuals are recognized from the same site: the
somewhat smaller paratype MMCH-Pv 60/1–6, featuring a cervical, caudal, right
ulna, metacarpal, right femur, and left tibia; MMCH-Pv 61/1, an even smaller
individual represented by a left femur; and MMCH-Pv 62/1–3, a larger
individual than the holotype, represented by a right femur, left tibia, and
left astragalus (Simón and Salgado 2023). Between all four of them, all areas
of the skeleton are represented except for the cranium, ribs, and sacrum,
although the vertebrae are kind of sparse.
</p>
<p>
With all of that material, <i>B. shiva</i> becomes one of the best represented
titanosaurs, and one of the best represented large titanosaurs. The dentary is of the rounded variety, not squared off like our
most recent guest
<i><a href="https://equatorialminnesota.blogspot.com/2023/11/your-friends-titanosaurs-inawentu.html" rel="nofollow" target="_blank">Inawentu oslatus</a></i>. It is low and had at least 12 teeth, but their exact shape is not known
because of poor preservation. The only known cervical is from the middle to
<a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow" target="_blank">posterior</a> part of the neck and 540 mm (21 in) long, albeit somewhat smooshed.
Interestingly, there are no foramina or pleurocoels. The one dorsal is notable
for having a hyposphene and hypantrum, which is interesting because of the
handful of other titanosaurs reputed to have this feature, two are also from
the Huincul Formation (<i>Cho. baileywillisi</i> and, controversially,
<i><a href="https://equatorialminnesota.blogspot.com/2018/08/your-friends-titanosaurs-3-andesaurus-antarctosaurus-argentinosaurus.html" rel="nofollow" target="_blank">Argentinosaurus huinculensis</a></i>). The caudals also have this articulation, but are otherwise rather
typically titanosaurian in form (procoelous, neural arches cheated anteriorly,
etc.) (Simón and Salgado 2023).
</p>
<p>
The forelimb is more complete than the hindlimb, and we can get a pretty good
idea of its proportions. For the right arm of the holotype, the humerus is 160 cm
(63 in) long (a bit odd compared to the 170 cm [67 in] length of the left humerus),
the ulna is 110 cm (43 in), the radius is 97 cm (38 in), and Metacarpal III is
53 cm (21 in), giving an animal with an arm about 3.1 m (122 in) long (Simón and
Salgado 2023). The longer of the two humeri is between that of
<a href="https://equatorialminnesota.blogspot.com/2020/03/your-friends-titanosaurs-22-paludititan-panamericansaurus-paralititan.html" rel="nofollow" target="_blank"><i>Paralititan stromeri</i></a>
and
<a href="https://equatorialminnesota.blogspot.com/2020/01/your-friends-titanosaurs-20-neuquensaurus-normanniasaurus-notocolossus.html" rel="nofollow" target="_blank"><i>Notocolossus gonzalezparejasi</i></a>, becoming the second-longest titanosaur humerus. Despite the size, the
humerus is on the gracile side. For the hindlimb, the only
complete femur is from the smallest individual, at 160 cm (63 in) long, while
the left tibia of the paratype is 110 cm (43 in) long. The femur is robust,
while the tibia and fibula are gracile (Simón and Salgado 2023).
</p>
<p>
Of course, the major talking point for <i>B. shiva</i> is its size. Clearly an
animal with the second-longest humerus known for a titanosaur and an arm about 3 meters long is going to be a
substantial animal. Simón and Salgado (2023), using limb bone circumferences,
presented an estimated range of about 50 to 84.5 metric tons (55 to 93.1 US
tons) for the holotype individual, which is not the largest known individual.
What is interesting to me is the Huincul Formation also produced
<i>Argentinosaurus</i> (still heavyweight champion) and the respectably sized
<a href="https://equatorialminnesota.blogspot.com/2023/02/your-friends-titanosaurs-chucarosaurus-ruixinia.html" rel="nofollow" target="_blank"><i>Chucarosaurus diripienda</i></a>, so it was clearly a good time for growing big titanosaurs. The Huincul is
also known for its
<a href="https://equatorialminnesota.blogspot.com/2018/11/rebbachisauridae.html" rel="nofollow" target="_blank">rebbachisaurids</a>, which conceivably were keeping the titanosaurs out of the smallish sauropod
niches. I do wish a bit more space had been devoted to differentiating
<i>B. shiva</i> from the three other named Huincul titanosaurs; there were
several comments comparing it to <i>Chu. diripienda</i>, but nothing for
<i>A. huinculensis</i> or <i>Cho. baileywillisi</i>. A paragraph or two to
summarize would have been appreciated. (At least it's better than the
<i>Inawentu</i> paper in that regard.) Phylogenetically, <i>B. shiva</i> is
found to be distant from <i>A, huinculensis</i>, as the sister to
Saltasauridae (<i><a href="https://equatorialminnesota.blogspot.com/2020/02/your-friends-titanosaurs-21-nullotitan-opisthocoelicaudia-overosaurus.html" rel="nofollow" target="_blank">Opisthocoelicaudia</a></i> + <a href="https://equatorialminnesota.blogspot.com/2020/07/your-friends-titanosaurs-27-ruyangosaurus-saltasaurus-sarmientosaurus.html" rel="nofollow" target="_blank"><i>Saltasaurus</i></a>) (Simón and
Salgado 2023). This is noteworthy for a couple of reasons, one being that
saltasaurids are otherwise basically only known from the last 20 million years or
so of the Cretaceous, another being that saltasaurids are not generally
noted for their size.
</p>
<p>References</p>
<p>
Simón, M. E. 2001. A giant sauropod from the Upper Cretaceous of El Chocon.
Ameghiniana 38(supplement to 4):19R.
</p>
<p>
Simón, M. E. 2011. Los dinosaurios saurópodos de la Formación Huincul
(Cenomaniano superior) en Villa El Chocón (Neuquén): osteología, relaciones
filogenéticas, aspectos paleoecológicos, y paleobiogeográficos. Thesis.
Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de
Córdoba, Córdoba, Argentina.
</p>
<p>
Simón, M. E., and L. Salgado. 2023.
<a href="https://app.pan.pl/article/item/app010862023.html" rel="nofollow" target="_blank">A new gigantic titanosaurian sauropod from the early Late Cretaceous of
Patagonia (Neuquén Province, Argentina)</a>. Acta Palaeontologica Polonica in press. doi:
<a href="https://doi.org/10.4202/app.01086.2023" rel="nofollow" target="_blank">https://doi.org/10.4202/app.01086.2023</a>.
</p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-89457837349879694092023-12-15T22:03:00.000-06:002023-12-15T22:03:02.398-06:0010 years of Equatorial Minnesota<p>
So... turns out I've been doing this 10 years. The
<a href="https://equatorialminnesota.blogspot.com/2013/12/equatorial-minnesota.html" rel="nofollow" target="_blank">very first post</a>
on Equatorial Minnesota went out December 15, 2013. Here we are, 409 posts and
one surprisingly sprawling
<a href="https://docs.google.com/spreadsheets/d/1NzXo_m3z-RlocqbkAL7QNf5q33qmT65uaut9okLOmqs/edit#gid=0" rel="nofollow" target="_blank">Compact Thescelosaurus</a>
later. I'm hoping there will be many more posts to come, because I still have
many ideas, even if the pace has slowed down (lots of other things going on).
</p>
<p>
For fun, here are some posts from the first five full years that I'm particularly fond of, for various reasons:
</p>
<p>2014:</p><ul style="text-align: left;"><li><a href="https://equatorialminnesota.blogspot.com/2014/02/practical-guide-to-mnrrametro-area.html" rel="nofollow" target="_blank">Practical guide to to MNNRA/metro-area bedrock geology</a> <br /></li><li>"The generic history of dinosaur paleontology" series (<a href="https://equatorialminnesota.blogspot.com/2014/07/the-generic-history-of-dinosaur_20.html" rel="nofollow" target="_blank">final part</a>)
</li><li>
<a href="https://equatorialminnesota.blogspot.com/2014/08/sponge-detective-when-faunal-lists-go.html" rel="nofollow" target="_blank">Sponge detective: when faunal lists go bad</a>
</li><li>
<a href="https://equatorialminnesota.blogspot.com/2014/10/a-brief-history-of-dinosaurs-on-internet.html" rel="nofollow" target="_blank">A brief history of dinosaurs on the Internet</a>
</li><li>
<a href="https://equatorialminnesota.blogspot.com/2014/10/designasaurus-ii.html" rel="nofollow" target="_blank">Designasaurus II</a>
</li></ul>
<p>2015:</p>
<ul style="text-align: left;"><li>
<a href="https://equatorialminnesota.blogspot.com/2015/02/historic-twin-cities-geologic-maps-and.html" rel="nofollow" target="_blank">Historic Twin Cities geologic maps and photos</a>
</li><li>
<a href="https://equatorialminnesota.blogspot.com/2015/02/reports-of-gut-contents-in-herbivorous.html" rel="nofollow" target="_blank">Reports of gut contents in herbivorous dinosaurs</a>
</li><li>
"Where are they now" series (<a href="https://equatorialminnesota.blogspot.com/2015/09/where-are-they-now-1980s-dinosaur.html" rel="nofollow" target="_blank">final part</a>)
</li><li>
<a href="https://equatorialminnesota.blogspot.com/2015/09/coming-attractions-in-dinosauria.html" rel="nofollow" target="_blank">Coming Attractions in Dinosauria?</a></li><li><a href="https://equatorialminnesota.blogspot.com/2015/12/nodosaurus-more-than-corduroy-armadillo.html" rel="nofollow" target="_blank"><i>Nodosaurus</i>: more than a corduroy armadillo</a>
</li></ul>
<p>2016: <br /></p><ul style="text-align: left;"><li><a href="https://equatorialminnesota.blogspot.com/2016/01/a-tale-of-two-packrat-species.html" rel="nofollow" target="_blank">A tale of two packrat species</a><i> <br /></i></li><li><a href="https://equatorialminnesota.blogspot.com/2016/02/gonioceras-when-nautiloid-is-also.html" rel="nofollow" target="_blank"><i>Gonioceras</i>: when a nautiloid is also a shovel-flounder</a></li><li><a href="https://equatorialminnesota.blogspot.com/2016/06/cambrian-island-hopping-at-taylors-falls.html" rel="nofollow" target="_blank">Cambrian island-hopping at Taylors Falls</a></li><li><i><a href="https://equatorialminnesota.blogspot.com/2016/06/stegopelta.html" rel="nofollow" target="_blank">Stegopelta</a></i> <br /></li><li><a href="https://equatorialminnesota.blogspot.com/2016/07/a-locked-dinosaur-mystery.html" rel="nofollow" target="_blank">A locked dinosaur mystery</a></li><li><a href="https://equatorialminnesota.blogspot.com/2016/07/former-ash-beds-in-st-paul.html" rel="nofollow" target="_blank">(former) Ash beds in St. Paul</a> </li><li><a href="https://equatorialminnesota.blogspot.com/2016/08/great-minnesota-brachiopod-caper.html" rel="nofollow" target="_blank">The Great Minnesota Brachiopod Caper of 1892</a></li><li><a href="https://equatorialminnesota.blogspot.com/2016/12/club-late-ordovician.html" rel="nofollow" target="_blank">Club Late Ordovician</a> </li></ul><p>2017: <br /></p><ul style="text-align: left;"><li><a href="https://equatorialminnesota.blogspot.com/2017/02/george-william-featherstonhaugh.html" rel="nofollow" target="_blank">George William Featherstonhaugh</a></li><li><a href="https://equatorialminnesota.blogspot.com/2017/04/further-adventures-in-mazomanie.html" rel="nofollow" target="_blank">Further adventures in the Mazomanie</a></li><li><a href="https://equatorialminnesota.blogspot.com/2017/07/limitations-of-the-layer-cake.html" rel="nofollow" target="_blank">The limitations of the layer cake</a></li><li><a href="https://equatorialminnesota.blogspot.com/2017/07/pipestone-scenella-cylindrocoelia.html" rel="nofollow" target="_blank">Follow-up: Pipestone National Monument, <i>Scenella</i>, <i>Cylindrocoelia</i></a> <br /></li><li><a href="https://equatorialminnesota.blogspot.com/2017/08/75-years-hadrosaurian-dinosaurs-of-north-america.html" rel="nofollow" target="_blank">75 years of "Hadrosaurian Dinosaurs of North America"</a></li><li><a href="https://equatorialminnesota.blogspot.com/2017/09/life-on-mill-street.html" rel="nofollow" target="_blank">Life on Mill Street</a></li></ul><p></p><p>2018:</p><ul style="text-align: left;"><li><a href="https://equatorialminnesota.blogspot.com/2018/01/practical-guide-to-st-croix-valley.html" rel="nofollow" target="_blank">Practical guide to St. Croix Valley sedimentary formations</a> </li><li><a href="https://equatorialminnesota.blogspot.com/2018/02/titanosaurs-all-way-down.html" rel="nofollow" target="_blank">Titanosaurs all the way down</a>, the start of the <a href="https://equatorialminnesota.blogspot.com/p/your-friends-titanosaurs.html" rel="nofollow" target="_blank">ongoing series</a> </li><li><a href="https://equatorialminnesota.blogspot.com/2018/02/identifying-invertebrate-fossils.html" rel="nofollow" target="_blank">Identifying invertebrate fossils</a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/07/fun-with-nautiloids-essay-in-futility.html" rel="nofollow" target="_blank">Fun with nautiloids: an essay in futility</a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/08/big-ordovician-brachiopods-strophomena.html" rel="nofollow" target="_blank">Big Ordovician brachiopods: <i>Strophomena</i> and friends</a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/08/lower-decorah-trilobites.html" rel="nofollow" target="_blank">Lower Decorah trilobites</a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/08/dryosaurus-elderae-nanosaurus-agilis.html" rel="nofollow" target="_blank"><i>Dryosaurus elderae</i> and the revenge of <i>Nanosaurus agilis</i></a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/11/rebbachisauridae.html" rel="nofollow" target="_blank">Rebbachisauridae</a></li><li><a href="https://equatorialminnesota.blogspot.com/2018/11/decorah-gastropods.html" rel="nofollow" target="_blank">Decorah gastropods (and some things that look like gastropods)</a></li></ul><p></p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-68926161416192349102023-12-10T20:41:00.002-06:002023-12-10T20:41:46.649-06:00Release the robotic Pleurocystites!<p>Speaking of paleobiology, here's a fun story that crossed my desk recently... <br /></p><p>If you've ever seen a fossil of <a href="https://equatorialminnesota.blogspot.com/2019/08/platteville-sea-stars-and-cystoids.html" rel="nofollow" target="_blank"><i>Pleurocystites</i></a> or <a href="https://equatorialminnesota.blogspot.com/2015/08/all-of-other-echinoderms.html" rel="nofollow" target="_blank">its ilk</a>, you've probably wondered what the heck it was doing in life (and perhaps how disturbing it may have looked while doing it). What once was confined to the realm of speculation now takes a step, or more accurately a kind of thrash, into the 21st century with the "Rhombot", a <a href="https://www.scientificamerican.com/article/robotics-revives-a-long-extinct-starfish-ancestor/" rel="nofollow" target="_blank">robotic pleurocystitid</a> detailed in <a href="https://www.pnas.org/doi/10.1073/pnas.2306580120" rel="nofollow" target="_blank">Desatnik et al. (2023)</a>.</p><p>The rhombots use the basic form of a pleurocystitid: central capsular body (theca), two short appendages (brachioles) at one end, one long appendage (stem) at the other end. The body plan is scaled-up in comparison to the real thing, and, of course, it is made of various artificial materials (many of which are not rigid, hence the "soft robotics" tag) rather than pleurocystitid stuff.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirOzMtiTWDBvlqOd4OYZo6UnlHGo6VPgucSSWh6AYD0irrtUSfxVJ8moH5oc0OuwL0TUKX6uIc5tvX5qi3371ZBzqLHC9ddQHUfdEM8eedD965x2n7uv5y14Cp3fqXVi-asZY6KhU5IydBHGIB87L7204sy_UAPvQJyNIltePCAwK7WkaMawt685lLtMO2/s3150/rhombot.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1454" data-original-width="3150" height="185" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirOzMtiTWDBvlqOd4OYZo6UnlHGo6VPgucSSWh6AYD0irrtUSfxVJ8moH5oc0OuwL0TUKX6uIc5tvX5qi3371ZBzqLHC9ddQHUfdEM8eedD965x2n7uv5y14Cp3fqXVi-asZY6KhU5IydBHGIB87L7204sy_UAPvQJyNIltePCAwK7WkaMawt685lLtMO2/w400-h185/rhombot.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Pleurocystitids, thrashing their way from Ordovician seafloors to the modern day via the rhombot (Figure 1, Desatnik et al. 2023) (<a href="https://creativecommons.org/licenses/by-nc-nd/4.0/" rel="nofollow">CC BY-NC-ND-4.0</a>).</td></tr></tbody></table><p></p><p>Granted, a rhombot is not a direct replica of a <i>Pleurocystites</i>. Assuming the living thing did indeed use its stem for propulsion, what can we gather from a robotic equivalent? First off, the rhombot was much more efficient with the stem moving it from behind rather than pulling it along. (This seems like a common-sense conclusion on first principles, so it's good to see it confirmed.) The stem also was more effective when used with a stiff sweep, rather than working with a sinuous motion. Finally, there was an optimal length for the stem (Desatnik et al. 2023). I encourage you to go to the linked article and see the movies of rhombots in action; they are not the most graceful robots, but pleurocystitids were probably not the most graceful animals.<br /></p><p></p><p>References</p><p>Desatnik, R., Z. J. Patterson, P. Gorzelak, S. Zamorad, P. LeDuca, and C. Majidi. 2023. <a href="https://www.pnas.org/doi/10.1073/pnas.2306580120" rel="nofollow" target="_blank">Soft robotics informs how an early echinoderm moved</a>. Proceedings of the National Academy of Sciences 120(46):e2306580120. doi: <a href="https://doi.org/10.1073/pnas.2306580120" rel="nofollow" target="_blank">https://doi.org/10.1073/pnas.2306580120</a>.<br /></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-60914968824362574522023-11-24T11:25:00.000-06:002023-11-24T11:25:07.282-06:00On the functioning of Thescelosaurus<p>
While it may seem that every paper on dinosaur paleobiology is about
<i>Tyrannosaurus rex</i>, or at least some kind of theropod, this is not true;
occasionally one slips out on a sauropodomorph or ornithischian. In the past
few weeks, in fact, two have come out on aspects of our old favorite
<i
><a
href="https://equatorialminnesota.blogspot.com/2014/11/thescelosaurus-hello-old-friend.html"
rel="nofollow"
target="_blank"
>Thescelosaurus</a
></i
>. Both feature North Carolina Museum of Natural Sciences (NCSM) 15728, also
known as "Willo" (the one formerly thought to have a fossil heart). The
earlier of the two, Senter and Mackey (2023), considers what
<i>Thescelosaurus</i> could do with its arms, and the more recent, Button and
Zanno (2023), sheds light on what may have been going on inside of its sharply
pointed skull.
</p>
<a name='more'></a>
<p>
<b><i>Thescelosaurus</i> forelimbs</b>
</p>
<p>
Between you and me, I've long been of the opinion that <i>Thescelosaurus</i>,
while aesthetically pleasing in many ways, had kind of funny-looking arms. In
particular, the
<a
href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html"
rel="nofollow"
target="_blank"
>humeri</a
>
look kind of long and slender for something that's so overbuilt elsewhere.
Then, of course, although the hands have five fingers, they're all pretty
stubby; this animal was certainly not doing needlepoint or picking locks.
Occasionally the proposal that <i>Thescelosaurus</i> was quadrupedal has
surfaced (e.g., Galton 1974), but it has never been especially popular.
Alternatively, one reconstruction, featured in Sternberg (1940), stuck the arm
out almost perpendicular to the body.
</p>
<p>
Senter and Mackey (2003) looked at the range of motion present at the shoulder
joint. <i>Thescelosaurus</i>, as it turns out, was fairly limited in what it
could do. In the parasagittal plane, the authors could not bring the humerus
farther forward than a bit short of vertical, so the animal could not reach
very far forward. It could, though, pull the humerus back to a bit above
horizontal, so the arm could be pulled back along the body. Laterally, the
humerus could be made to stick out, but this was not described anywhere as the
natural position. With the natural curvature of the
<a
href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html"
rel="nofollow"
target="_blank"
>anterior</a
>
part of the torso into the neck, the arms are long enough to touch the ground,
but this would not have been useful for mobility because the hands cannot be
rotated correctly: instead of a solid pull by a hand placed flat on the ground
and retracted, with fingers pointing in the direction of travel, the animal
would instead have been delivering a karate chop to the ground at best.
</p>
<table
align="center"
cellpadding="0"
cellspacing="0"
class="tr-caption-container"
style="margin-left: auto; margin-right: auto;"
>
<tbody>
<tr>
<td style="text-align: center;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg42sazJGAmKnb6JYjphOyJEPsBV8zY5qWEM4qhAvSxbIuEs03rLN_60JGQxSXzZo0LjYgYsFU4wG6BqV3zBipRppBckW1scpGco85ghxFAI4PmN7kGQLh0kHxRLUCQo5kXD5lg-AmZkDu4K8I9_Y06rUBUu41mSjE3yMusBqie7UkPVtTxjRwPwZeXzIiU/s1067/senter_mackey_2023_fig_2.jpg"
style="margin-left: auto; margin-right: auto;"
><img
border="0"
data-original-height="1067"
data-original-width="800"
height="400"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg42sazJGAmKnb6JYjphOyJEPsBV8zY5qWEM4qhAvSxbIuEs03rLN_60JGQxSXzZo0LjYgYsFU4wG6BqV3zBipRppBckW1scpGco85ghxFAI4PmN7kGQLh0kHxRLUCQo5kXD5lg-AmZkDu4K8I9_Y06rUBUu41mSjE3yMusBqie7UkPVtTxjRwPwZeXzIiU/w300-h400/senter_mackey_2023_fig_2.jpg"
width="300"
/></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Or perhaps this would make more sense than my secondhand ramblings? This
is
<a
href="https://palaeo-electronica.org/content/2023/784-1289/3988-forelimb-function-figures#f2"
rel="nofollow"
target="_blank"
>Figure 2</a
>
from Senter and Mackey (2023), which see for the extensive caption.
<a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow"
>CC BY 4.0</a
>.
</td>
</tr>
</tbody>
</table>
<p>
<b>The brain of <i>Thescelosaurus</i></b>
</p>
<p>A farewell to arms? We'll see...</p>
<p>
NCSM 15728 also happens to have a pretty good head on its shoulders, which is
analyzed in Button and Zanno (2023). The authors used CT-scanning of the skull
to create a digital endocast of the brain. This turned out to be in the
average to below-average range for NCSM's mass, more comparable to ceratopsids
and thyreophorans than other ornithopod-types. Of course, one can have a
proportionally or absolutely huge brain and not be doing much with it, as many
humans have proved over the years, although we can be comfortable in assuming
that <i>Thescelosaurus neglectus</i> did not produce, for example, many chess
masters (despite the cerebral hemispheres occupying about 30% of the
endocast). What <i>was</i> it doing?
</p>
<table
align="center"
cellpadding="0"
cellspacing="0"
class="tr-caption-container"
style="margin-left: auto; margin-right: auto;"
>
<tbody>
<tr>
<td style="text-align: center;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN-XIZuDSBADwo4I6QTt7FYPHTe6ATtgEWmP6D4S3oA7mWHCWFVf_HAJ4PNHiYEJHkdx3XoZz2ct_gRjB9ErWh3bh333FBRx3vuChZUNazhJD_Yg_10vh5307VXPt0MlUzsxe1-lmCtFvc86J_haPu4mcOSD28ENFT-bxe_wH90oSVDV8MLx4S4Dlg6eak/s1810/button_zanno_2023_fig_1.jpg"
style="margin-left: auto; margin-right: auto;"
><img
border="0"
data-original-height="1810"
data-original-width="1499"
height="400"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN-XIZuDSBADwo4I6QTt7FYPHTe6ATtgEWmP6D4S3oA7mWHCWFVf_HAJ4PNHiYEJHkdx3XoZz2ct_gRjB9ErWh3bh333FBRx3vuChZUNazhJD_Yg_10vh5307VXPt0MlUzsxe1-lmCtFvc86J_haPu4mcOSD28ENFT-bxe_wH90oSVDV8MLx4S4Dlg6eak/w331-h400/button_zanno_2023_fig_1.jpg"
width="331"
/></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
<a
href="https://www.nature.com/articles/s41598-023-45658-3/figures/1"
rel="nofollow"
target="_blank"
>Figure 1</a
>
in Button and Zanno (2023), which see for caption.
<a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow"
>CC BY 4.0</a
>. Was there a thescelosaur Descartes, and a thescelosaur "<a
href="https://en.wikipedia.org/wiki/Cogito,_ergo_sum"
rel="nofollow"
target="_blank"
>Cogito, ergo sum</a
>"?
</td>
</tr>
</tbody>
</table>
<p>One thing that it was probably quite good at was smelling things. The
olfactory bulbs make up about 3% of the endocast volume, which is something you
might find in rodents and rabbits. On the other hand, it was not enjoying an
especially rich world of sounds. The best hearing range is calculated at about
296 to 2150 Hz, topping out at 3051 Hz, and mean best hearing around 1100 to
1200 Hz. Button and Zanno (2023) note that this is less than other
ornithopod-types, but very similar to some crocs, such as the
<a
href="https://en.wikipedia.org/wiki/Spectacled_caiman"
rel="nofollow"
target="_blank"
>spectacled caiman</a
>, and some lizards, such as the
<a
href="https://en.wikipedia.org/wiki/Chalcides_ocellatus"
rel="nofollow"
target="_blank"
>ocellated skink</a
>. (This is also rather similar to <i>Struthiosaurus austriacus</i> per Schade
et al. 2022,
<a
href="https://equatorialminnesota.blogspot.com/2022/01/passing-thoughts-on-struthiosaurus-and.html"
rel="nofollow"
target="_blank"
>as we saw a couple of years ago</a
>.) The short cochlear duct also indicates relatively poor ability to
discriminate low- and high-frequency sounds. The semicircular canals indicate
the skull was routinely held at a slight upward tilt. The anterior semicircular
canal is unusually long and slender; its length may imply a great sensitivity to
balance.</p>
<p>
Button and Zanno draw some inferences about the possible lifestyle of
<i>T. neglectus</i> from these data. The relatively small brain indicates it
may not have had as complex a social life as, say, a hadrosaur, with smaller
group sizes. This would also fit with the relatively limited hearing: it
wouldn't have had as great a need to communicate with others of the same
species. (Borrowing from Wikipedia, the spectacled caiman apparently has a
repertoire of nine different calls, so there's no need to think of
<i>Thescelosaurus</i> as entirely solitary and non-vocal.) The enhanced sense
of smell is comparable to ankylosaurs, which are sometimes interpreted as
scratch-diggers for food like roots and tubers, so we have come back around to
arms. Senter and Mackey (2023) show the arms could be pulled back farther than
they could reach forward, but we still have the issue of the non-pronating
wrists. Some features of the brain suggest the animal was not especially
agile, but the sensitivity for balance may be a feature for living in swampy
or marshy areas. Button and Zanno comment on the possibility that some of the
brain anatomy may be adaptations for burrowing, a la <i>Oryctodromeus</i>, or
at least represent a past evolutionary history of burrowing. This in turn has
implications for some of our common narratives about surviving the
end-Cretaceous extinction: If <i>Thescelosaurus</i> could burrow, then
burrowing was not a "get-out-of-extinction" card.
</p>
<p><b>References</b></p>
<p>
Button, D. J., and L. E. Zanno. 2023.
<a
href="https://www.nature.com/articles/s41598-023-45658-3"
rel="nofollow"
target="_blank"
>Neuroanatomy of the Late Cretaceous
<i>Thescelosaurus neglectus</i> (Neornithischia: Thescelosauridae) reveals
novel ecological specialisations within Dinosauria</a
>. Scientific Reports 13(1):19224. doi:
<a
href="https://doi.org/10.1038/s41598-023-45658-3"
rel="nofollow"
target="_blank"
>https://doi.org/10.1038/s41598-023-45658-3</a
>.
</p>
<p>
Galton, P. M. 1974. Notes on <i>Thescelosaurus</i>, a conservative ornithopod
dinosaur from the Upper Cretaceous of North America, with comments on
ornithopod classification. Journal of Paleontology 48(5):1048–1067.
</p>
<p>
Schade, M., S. Stumpf, J. Kriwet, C. Kettler, and C. Pfaff. 2022.
<a
href="https://www.nature.com/articles/s41598-021-03599-9"
rel="nofollow"
target="_blank"
>Neuroanatomy of the nodosaurid
<i>Struthiosaurus austriacus</i> (Dinosauria: Thyreophora) supports
potential ecological differentiations within Ankylosauria</a
>. Scientific Reports 12:article 144. doi:
<a href="https://doi.org/10.1038/s41598-021-03599-9"
>https://doi.org/10.1038/s41598-021-03599-9</a
>.
</p>
<p>
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Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-1812448583690799902023-11-06T21:51:00.000-06:002023-11-06T21:51:45.549-06:00Your Friends The Titanosaurs: Inawentu oslatus<p>Our latest guest in the series is <i>Inawentu oslatus</i> from the middle Late Cretaceous of Argentina. <i>I. oslatus</i> is more than your average new titanosaur; it is one of the two major unnamed titanosaurs <a href="https://equatorialminnesota.blogspot.com/2021/05/your-friends-titanosaurs-362-coming-attractions-europe-south-america.html" rel="nofollow" target="_blank">discussed</a> a couple of years back, MAU-Pv-LI-595. This is the more recently discovered of the two skull-bearing titanosaurs from Rincón de los Sauces (the other is MAU-Pv-AC-01).</p><span><a name='more'></a></span><p></p><p><u>Genus and Species</u>: <i>Inawentu oslatus</i>. "Inawentu" is a <a href="https://en.wikipedia.org/wiki/Mapuche_language" rel="nofollow" target="_blank">Mapundung</a> word meaning "imitator" or "mimic", and alludes to the strong similarity to <a href="https://equatorialminnesota.blogspot.com/2018/11/rebbachisauridae.html" rel="nofollow" target="_blank">rebbachisaurids</a>. "Oslatus" combines Latin words for "mouth" ("os") and "broad" ("latus"), because the business end of the skull is broad (Filippi et al. 2023). Combined, we get something like "broad-mouthed imitator".</p><p><u>Citation</u>: Filippi, F. S., R. D. Juárez Valieri, P. A. Gallina, A. H. Méndez, F. A.
Gianechini, and A. C. Garrido. 2023. A rebbachisaurid-mimicking
titanosaur and evidence of a Late Cretaceous faunal disturbance event in
South-West Gondwana. Cretaceous Research 105754 (online pre-proof). doi: <a href="https://doi.org/10.1016/j.cretres.2023.105754" rel="nofollow" target="_blank">https://doi.org/10.1016/j.cretres.2023.105754</a>. (Thanks to Skye McDavid for sending me a copy!)<br /></p><p></p><p><u>Geography and Stratigraphy</u>: The type and only known specimen was found near the top of the Upper Cretaceous (<a href="https://equatorialminnesota.blogspot.com/p/geologic-time.html" rel="nofollow" target="_blank">Santonian</a>) Bajo de la Carpa Formation, 11.1 m (36.4 ft) below the Anacleto Formation, in floodplain mudstones. The location is in the La Invernada area, southwest of Rincón de los Sauces in the Neuquén Basin of Patagonia, Neuquén, Argentina (Filippi et al. 2023).</p><p><u>Holotype</u>: MAU-Pv-LI-595 (Museo Municipal Argentino Urquiza, Rincón de los Sauces, Neuquén, Argentina), an articulated partial skeleton including a nearly complete skull and lower jaws, a complete vertebral column from the <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow" target="_blank">atlas</a> to the end of the sacrum, cervical and sacral ribs, and both ilia (Filippi et al. 2023).<br /></p><p>MAU-PV-LI-595 is an articulated specimen, a rarity among titanosaurs, which have historically preferred bonebeds (with bonus points for multiple species). A largely complete skull plus complete cervical, dorsal, and sacral series vaults <i>I. oslatus</i> into the inner circle of titanosaur completeness and will no doubt make it an important point for comparison, given how important vertebrae are for differentiating species. Preservation quality is mixed, and it is thought that other bones were lost to erosion (Filippi et al. 2023). (Drat.)</p><p>The skull as preserved looks a bit like someone pulled the muzzle down and away from the rest of the skull. The <a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow" target="_blank">anterior</a> margin of the jaw is more or less squared off. The maxillae flare laterally, but the lower jaw does not. The actual tooth-bearing portion of the upper jaw appears to be absent, but I count 14 tooth positions in the figured dentary, with simple peg-like teeth. Compared to <a href="https://equatorialminnesota.blogspot.com/2019/01/your-friends-titanosaurs-8-bonitasaura-borealosaurus-brasilotitan.html" rel="nofollow" target="_blank"><i>Bonitasaura salgadoi</i></a>, the other squarish-jawed titanosaur known from fairly complete skull material, there are a number of differences, such as: the antorbital fenestrae are long skinny slots rather than broad ellipsoids; the lateral temporal fenestrae are constricted into two small holes each; the external naris has at least part of a midline bar (as opposed to being a simple hole); and the foramen magnum, through which the spinal cord passes, is oriented facing the bottom of the skull rather than the posterior. This last point is notable because it means the skull, when held neutrally, made almost a right angle with the neck. Hold the neck near horizontal, and the snout is pointed straight down.<br /></p><p>The neck is proportionally short for a sauropod. There are only 12 cervicals (the fewest of any titanosaur to date) and they are relatively short (Filippi et al. 2023). Most of them look rather similar except for size, with simple triangular neural spines and short cervical ribs generally about the length of their verts or slightly longer. Things change around the base of the neck, with the neural spines becoming shorter fore-aft with C11, then C12 being quite short lengthwise with a distinctly angled profile, rising up anteriorly. The first dorsal also is stepped up anteriorly, indicating an anatomically enforced rise of the neck at its base. The dorsals mostly have low neural spines, generally swept posteriorly back to the sacrum, where the angle becomes close to vertical. The last sacral indicates a procoelous first caudal. The ilia are long and rather low but not notably broad (Filippi et al. 2023). The neural arches are more or less all there (i.e., missing bits are due to erosion, not lack of fusion), indicating we aren't looking at a juvenile. However, the type specimen was not a particularly large sauropod, on the order of 10 m (33 ft) long judging from Filippi et al.'s restoration.<br /></p><p>As its name hints, <i>I. oslatus</i> has a lot in common with rebbachisaurs, including a broad squared-off snout with small slender teeth packed into the front, a skull oriented steeply downward with respect to the neck, a relatively short neck, short cervical ribs, and smallish body size. The jaw characteristics are known from several other titanosaurs (<i><a href="https://equatorialminnesota.blogspot.com/2018/08/your-friends-titanosaurs-3-andesaurus-antarctosaurus-argentinosaurus.html" rel="nofollow" target="_blank">Antarctosaurus wichmannianus</a></i>, <i><a href="https://equatorialminnesota.blogspot.com/2018/12/your-friends-titanosaurs-part-75-baalsaurus.html" rel="nofollow" target="_blank">Baalsaurus mansillai</a></i>, <i>Bo. salgadoi</i>, <i><a href="https://equatorialminnesota.blogspot.com/2019/01/your-friends-titanosaurs-8-bonitasaura-borealosaurus-brasilotitan.html" rel="nofollow" target="_blank">Brasilotitan nemophagus</a></i>), so we should expect them to share at least some of these other general features as well. There is rather little anatomical overlap with most of them except for the mandibles, though. (<i>A. wichmannianus</i> is overdue for a redescription, which could be done in comparison to <i>I. oslatus</i> and <i>Bo. salgadoi</i> to see what of the associated postcranial elements might most likely pertain to it.) Rebbachisaurs appear to have shuffled off their mortal coil around the end of the Cenomanian, 8 million years or so before <i>I. oslatus</i>'s appearance in the Santonian. Whatever had caused the rebbachisaurs' ecological role to go sour must not have persisted, if within 8 million years a branch of titanosaurs had waltzed in and made it their own. (And you haven't lived until you have seen waltzing sauropods.)<br /></p><p>Unsurprisingly, Filippi et al.'s phylogenetic analysis places <i>I. oslatus</i> close to several of the other square-jawed titanosaurs: <i>A. wichmannianus</i>, <i>Ba. mansillai</i>, and <i>Bo. salgadoi</i>. <i>Br. nemophagus</i> is in the neighborhood but more remote, which is interesting. In fact, it is actually found to be closer to a clade consisting of <a href="https://equatorialminnesota.blogspot.com/2020/07/your-friends-titanosaurs-part-26-rinconsaurus-rocasaurus-rukwatitan.html" rel="nofollow" target="_blank">Rinconsauria</a> and <a href="https://equatorialminnesota.blogspot.com/2018/07/your-friends-titanosaurs-2-aeolosaurus.html" rel="nofollow" target="_blank">Aeolosaurini</a>. The Rinconsauria+Aeolosaurini clade plus the unnamed square-jawed clade make up Filippi et al.'s "Clade A", distinct from groups such as saltasaurs and lognkosaurs. It is not unheard of for rinconsaurs to be found with aeolosaurs or with square-jaws (<i>Bo. salgadoi</i>), but this particular configuration appears to be unique to date in the literature.</p><p>The description did not go into it, but the Bajo de la Carpa Formation has several other named titanosaurs, and it's worth having a quick look at them. <i>Bonitasaura salgadoi</i> we've already mentioned, with several significant differences from <i>I. oslatus</i> in the skull alone. Next is <i><a href="https://equatorialminnesota.blogspot.com/2019/11/your-friends-titanosaurs-18-mendozasaurus-microcoelus-mnyamawamtuka.html" rel="nofollow" target="_blank">Microcoelus patagonicus</a></i>, based on a partial anterior dorsal. This doesn't seem to be a good match with <i>I. oslatus</i>, but that's just based on eyeballing figures. Next is the aeolosaur <i><a href="https://equatorialminnesota.blogspot.com/2020/02/your-friends-titanosaurs-21-nullotitan-opisthocoelicaudia-overosaurus.html" rel="nofollow" target="_blank">Overosaurus paradasorum</a></i>, which overlaps quite nicely from the posterior cervicals to the sacrum and ilia. There are some similarities, such as the abrupt angle at the base of the neck, but the two can be distinguished by features such as the form and angle of the neural spines and the general shape of the ilia. <i><a href="https://equatorialminnesota.blogspot.com/2020/07/your-friends-titanosaurs-part-26-rinconsaurus-rocasaurus-rukwatitan.html" rel="nofollow" target="_blank">Rinconsaurus caudamirus</a></i> does not overlap quite as well, but can also be distinguished by the vertebrae and ilia. <a href="https://equatorialminnesota.blogspot.com/2020/11/your-friends-titanosaurs-30-part-2-more-titanosaurus.html" rel="nofollow" target="_blank">"Titanosaurus" <i>nanus</i></a> includes both a cervical and a dorsal, neither of which are complete; neither look much like their corresponding number in <i>I. oslatus</i>. Finally, there is <i><a href="https://equatorialminnesota.blogspot.com/2020/10/your-friends-titanosaurs-29-tapuiasaurus-tengrisaurus-traukutitan.html.html" rel="nofollow" target="_blank">Traukutitan eocaudata</a></i>, which has no anatomical overlap with <i>I. oslatus</i>, but is unlikely to be the same thing simply based on size: <i>T. eocaudata</i> includes a femur 1.85 m [6.07 ft] long and caudals with unfused neural arches. The Bajo de la Carpa Formation just seems to represent a good place for titanosaur diversity, with aeolosaurs, a couple square-jaws, rinconsaurs, saltasaurs, and potential lognkosaurs.<br /></p><p>References</p><p>Filippi, F. S., R. D. Juárez Valieri, P. A. Gallina, A. H. Méndez, F. A. Gianechini, and A. C. Garrido. 2023. A rebbachisaurid-mimicking titanosaur and evidence of a Late Cretaceous faunal disturbance event in South-West Gondwana. Cretaceous Research 105754 (online pre-proof). doi: <a href="https://doi.org/10.1016/j.cretres.2023.105754" rel="nofollow" target="_blank">https://doi.org/10.1016/j.cretres.2023.105754</a>.</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-49580187313718955192023-10-29T11:33:00.001-05:002023-10-29T11:33:34.053-05:00Fossils at Airports<p>This year's annual Society of Vertebrate Paleontology meeting was held in Cincinnati, and I was quite pleased to be greeted in Concourse B of Cincinnati/Northern Kentucky Airport by a mastodon skeleton.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7_q8CQ-AFJaDUXE52BOh8H1v4onItXh_6iEANR0ApfRIdGUMBwijnEbl4iZ1QzRNPcjEl8auOdbBehraL4HxqSAVsnUJYwp8asNZAkbiZ9CBs91nXgMkxcbUlJ_45JdVJ1UkEXNs-R6Xub_H3xwzkQyoUNK_c_ffXvO4PlDbGuowf87A7x54UHWKEI826/s3659/cvg_mastodon.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2037" data-original-width="3659" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7_q8CQ-AFJaDUXE52BOh8H1v4onItXh_6iEANR0ApfRIdGUMBwijnEbl4iZ1QzRNPcjEl8auOdbBehraL4HxqSAVsnUJYwp8asNZAkbiZ9CBs91nXgMkxcbUlJ_45JdVJ1UkEXNs-R6Xub_H3xwzkQyoUNK_c_ffXvO4PlDbGuowf87A7x54UHWKEI826/w400-h223/cvg_mastodon.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">This seemed like a good omen.<br /></td></tr></tbody></table><p></p><p>This is hardly the only airport to have fossils. Sometimes they are part of the building stone; at Minneapolis–St. Paul International Airport, for example, you can hardly walk around without seeing fossils in the (non-local) flooring stone. Most of the fossils are bits and pieces of shells, but there are some nice coiled cephalopods, and if you have time they're certainly worth a pause. (It would be fun to do a thorough photographic inventory, but I imagine it would probably have to be explained so as not to appear nefarious.)</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWrcUs4-QbHGSOykUWw4866DacsJkffohyphenhyphenS1T8en5eyWzkWKZjk3GAV35PyPnKu11-65DMeKEerDNNNO6Kk2F3pCYMlYTc_FYiOahqACatoI_5HNM2FsTg7ZeqVz-X7tFkfCTr6muzIInEBUYcI7y9s_oPOxbf-mbeMprRaPDR2ZLfkm6tEgrnW2zFonO4/s2139/msp_cephalopods.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1720" data-original-width="2139" height="321" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWrcUs4-QbHGSOykUWw4866DacsJkffohyphenhyphenS1T8en5eyWzkWKZjk3GAV35PyPnKu11-65DMeKEerDNNNO6Kk2F3pCYMlYTc_FYiOahqACatoI_5HNM2FsTg7ZeqVz-X7tFkfCTr6muzIInEBUYcI7y9s_oPOxbf-mbeMprRaPDR2ZLfkm6tEgrnW2zFonO4/w400-h321/msp_cephalopods.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Two cephalopods with part of my foot for scale.<br /></td></tr></tbody></table><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgt_pE6WHL1YL4Y6mYeAYsrVdrrgK_AWmAB24vICSnd7SyDkPWbKJqbZt7PJ-z8WfYJ8_jRiUpj4pInrlgu2-5yjcSDQXsgZfwV4mXEMlmEL87yjqRMpwrwS3roXw7R-foR6pSrti0IBwFL4sYi0A8uUdsoRu4eCushkoLS2MZKt8Ph0fDZiOvOWvpVapPA/s4608/msp_stairs.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3456" data-original-width="4608" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgt_pE6WHL1YL4Y6mYeAYsrVdrrgK_AWmAB24vICSnd7SyDkPWbKJqbZt7PJ-z8WfYJ8_jRiUpj4pInrlgu2-5yjcSDQXsgZfwV4mXEMlmEL87yjqRMpwrwS3roXw7R-foR6pSrti0IBwFL4sYi0A8uUdsoRu4eCushkoLS2MZKt8Ph0fDZiOvOWvpVapPA/w400-h300/msp_stairs.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A generous assortment of large fossil debris.<br /></td></tr></tbody></table><p></p><p>In other cases the fossils are on display, as at Cincinnati. One of my favorite examples is the <i>Brachiosaurus</i> at Chicago O'Hare. I've become fairly familiar with this mount over the years since I first saw it on the way to Mongolia, as O'Hare has been practically a required stop on my trips east from MSP.</p><p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwRElI3mLyfsncNmxyQVh44DsWfl2hnQSC_5GrMO86NqIZUpv2Hll60lPtVZJRXWHK6ElVyW59LXSNYaI56GE6pxqv3e2ifhyphenhyphenNb10kyLBTkQmwD_nS77MWmHulqWxvAsdTbRPabZJkmarXF2rjUJnKri-WbVUrw0DWIoy8pecJKuLtkhLPXq0FRybAYtV1/s3264/ord_bears_brach.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3264" data-original-width="1840" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwRElI3mLyfsncNmxyQVh44DsWfl2hnQSC_5GrMO86NqIZUpv2Hll60lPtVZJRXWHK6ElVyW59LXSNYaI56GE6pxqv3e2ifhyphenhyphenNb10kyLBTkQmwD_nS77MWmHulqWxvAsdTbRPabZJkmarXF2rjUJnKri-WbVUrw0DWIoy8pecJKuLtkhLPXq0FRybAYtV1/w225-h400/ord_bears_brach.jpg" width="225" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">On this visit in 2019 the brachiosaur was decked out in Chicago Bears livery for the NFL's centenary.<br /></td></tr></tbody></table></p><p>Back to Cincinnati. (Well, not literally; the airport is actually across the Ohio River in Kentucky.) In the mastodon photo above another skeleton can be seen in the distance. I'd been in a hurry when I arrived, so I hadn't explored farther, but made it a point to do so when I departed. It turned out there were five more mounts in the concourse, which makes me wonder if there were any in Concourse A. The animals chosen for exhibit are all typical Ice Age fauna of the area (in fact, all have been found at <a href="https://parks.ky.gov/union/parks/historic/big-bone-lick-state-historic-site" rel="nofollow" target="_blank">Big Bone Lick</a> not too far down the river). One notable absence, if only by name, was the giant beaver <i><a href="https://equatorialminnesota.blogspot.com/2014/01/platteville-follies-crushed-giant.html" rel="nofollow" target="_blank">Castoroides ohioensis</a></i>, so I kind of hope there were more in Concourse A.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpVEzE_A_uRzYhOcmyxwCi-wxhh1fu4QZV4Je5HdoiyZUUl1zi_te2pTx3oJXsoqDD3ZkdpruSaHF5DxnpsSEn-SICIECwbkqBgXN20qHKP9ScLy5mDb2TsA_PdrSYVPWU0wEgBJoxwclaKjWeNdBeQOFiOqTVv_7AD_ie74iOVEmBCIeWtHNAU_ghVfS2/s3137/cvg_cervalces.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2282" data-original-width="3137" height="291" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpVEzE_A_uRzYhOcmyxwCi-wxhh1fu4QZV4Je5HdoiyZUUl1zi_te2pTx3oJXsoqDD3ZkdpruSaHF5DxnpsSEn-SICIECwbkqBgXN20qHKP9ScLy5mDb2TsA_PdrSYVPWU0wEgBJoxwclaKjWeNdBeQOFiOqTVv_7AD_ie74iOVEmBCIeWtHNAU_ghVfS2/w400-h291/cvg_cervalces.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Cervalces scotti</i>, the "stag-moose"; think of a moose with fancier antlers.<br /></td></tr></tbody></table><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1wc7Izi2jez1_FnGEduHlXLduBXOLQtrBAyXo9AV5t-yOU1pPthrRk5SLr5E6GOwOfqKv3rdQRLC9XjzMt1a9SzzXjYzTXm0t50WZ2i-7Ruf7M-GdpKBheIgRpaD3jAtoitHJyBpEojcBDZAHrIwlv68p0K_t9DBzFy0Mt0cTn3ILrVVG93wNPZURxi4l/s2815/cvg_dire_wolf_peccary.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1522" data-original-width="2815" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1wc7Izi2jez1_FnGEduHlXLduBXOLQtrBAyXo9AV5t-yOU1pPthrRk5SLr5E6GOwOfqKv3rdQRLC9XjzMt1a9SzzXjYzTXm0t50WZ2i-7Ruf7M-GdpKBheIgRpaD3jAtoitHJyBpEojcBDZAHrIwlv68p0K_t9DBzFy0Mt0cTn3ILrVVG93wNPZURxi4l/w400-h216/cvg_dire_wolf_peccary.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A dire wolf pursues an extinct peccary. </td></tr></tbody></table><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh13Jx_i7P6wWULvsVqu7Sgk5Yz_sbdLi2iLMbrAPXQbdKbNJ1bHfSWCwbc5YoUC7lR3EBTiEnEH2Rf1zCAz16Fc10Mw8Sfy_D7kwQGIq3pMZ0ZNC4YqhHYFzS4ryRa_MalJPrtpjSSs8GajyopsRyC2Mfj_Lsqiyfj_1RS6Dozr59hSDuWGVIkc-xHjnl3/s2751/cvg_sloth.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1805" data-original-width="2751" height="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh13Jx_i7P6wWULvsVqu7Sgk5Yz_sbdLi2iLMbrAPXQbdKbNJ1bHfSWCwbc5YoUC7lR3EBTiEnEH2Rf1zCAz16Fc10Mw8Sfy_D7kwQGIq3pMZ0ZNC4YqhHYFzS4ryRa_MalJPrtpjSSs8GajyopsRyC2Mfj_Lsqiyfj_1RS6Dozr59hSDuWGVIkc-xHjnl3/w400-h263/cvg_sloth.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A giant ground sloth; the mounts are convenient to walk around, particularly nice for appreciating the unusual anatomy of this animal.<br /></td></tr></tbody></table><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0oXwkgzBE3ro7QJupNg0E9UDKEokeUr3wTs9tbLzpefsTuNhApcmVVpk9pnYlJmMz4FF5frp3zdhlAKcJoZcDND7xi2-oZctF6g89tVapR_Ms-DyM-kI3D4Yl7WLqFZIBSaUy6JW93XAYndeerhrwhCtP978ZIoxPna9wiaGXuXzF_fPCEAQ-iUOMnmD0/s2435/cvg_smilodon.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1913" data-original-width="2435" height="314" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0oXwkgzBE3ro7QJupNg0E9UDKEokeUr3wTs9tbLzpefsTuNhApcmVVpk9pnYlJmMz4FF5frp3zdhlAKcJoZcDND7xi2-oZctF6g89tVapR_Ms-DyM-kI3D4Yl7WLqFZIBSaUy6JW93XAYndeerhrwhCtP978ZIoxPna9wiaGXuXzF_fPCEAQ-iUOMnmD0/w400-h314/cvg_smilodon.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A <i>Smilodon</i> smiling.<br /></td></tr></tbody></table>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-75450231788634158002023-10-08T14:44:00.002-05:002023-11-23T08:55:58.913-06:00Compact Thescelosaurus Year Eight<p>
It's that time again, for
<a href="https://www.nps.gov/subjects/fossilday/index.htm" rel="nofollow" target="_blank">National Fossil Day</a>
(October 11 this year), a new sheet for
<a href="https://docs.google.com/spreadsheets/d/1NzXo_m3z-RlocqbkAL7QNf5q33qmT65uaut9okLOmqs/edit#gid=0" rel="nofollow" target="_blank">The Compact Thescelosaurus</a>, and the annual summary of what was added to the spreadsheet in the past 12
months. In addition to National Fossil Day events this month, the latest issue
of
<a href="https://www.nps.gov/subjects/fossils/newsletters.htm" rel="nofollow" target="_blank">Park Paleontology News</a>
is up for viewing. Also in breaking NPS paleontology news:
<a href="https://www.science.org/doi/10.1126/science.adh5007" rel="nofollow" target="_blank">additional dating of the fossil human tracks</a>
at White Sands National Park, and a
<a href="https://www.researchgate.net/publication/374331991_A_Tyrannosaur_Dinosauria_Theropoda_Tyrannosauridae_from_the_Late_Cretaceous_Maastrichtian_Harebell_Formation_of_Yellowstone_National_Park_Wyoming" rel="nofollow" target="_blank">previously overlooked record</a>
of a tyrannosaur tooth at Yellowstone National Park. [Update, 2023/10/10: And a tritylodont bonebed at Glen Canyon National Recreation Area was <a href="https://www.nps.gov/glca/learn/news/20231006.htm" rel="nofollow" target="_blank">just announced</a>; goes well with <a href="https://giw.utahgeology.org/giw/index.php/GIW/article/view/128" rel="nofollow" target="_blank">this new paper</a> on a massive track block from the recreation area, too.]<br /></p>
<p>
Here at Equatorial Minnesota, we've passed
<a href="https://equatorialminnesota.blogspot.com/2023/07/your-friends-titanosaurs-igai-semkhu.html" rel="nofollow" target="_blank">400 entries</a>
this year. Later this year, December 15 will mark
<a href="https://equatorialminnesota.blogspot.com/2013/12/equatorial-minnesota.html" rel="nofollow" target="_blank">10 years</a>
of posting. (Also, anyone know why
<a href="https://equatorialminnesota.blogspot.com/2018/07/fun-with-nautiloids-essay-in-futility.html" rel="nofollow" target="_blank">this nautiloid post</a>
would have spiked in interest?) The Compact Thescelosaurus has been around for
8 of those years, and it's traditional to add a new sheet. For this year,
first I considered all of Pseudosuchia (except for the aetosaurs, covered
already), but decided against it due to the number of species. I then looked
at doing just Mesozoic pseudosuchians before being discouraged by whatever it
is Thalattosuchia has been doing over the past 200 years. So, for now it's
just Triassic forms, with the intent to expand over time.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmvN5-InN5aVCAICxh0Xd6DcLZsu0l-gNh3VcvA322oFxPJydhOGF_FZl2Y1z_tI3qixm-xIdMCJvbYNbYFZAe-e3WCij0gJt5UN0wj7XFExV5Nb5NwtQKZ2gfObR2MApKqO4puiWsjoVF-kEs_uAO0-7gZ4Rv6rzdu90z9yxDuItjmf4-XG6PQe830n65/s4424/prestosuchus.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2827" data-original-width="4424" height="204" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmvN5-InN5aVCAICxh0Xd6DcLZsu0l-gNh3VcvA322oFxPJydhOGF_FZl2Y1z_tI3qixm-xIdMCJvbYNbYFZAe-e3WCij0gJt5UN0wj7XFExV5Nb5NwtQKZ2gfObR2MApKqO4puiWsjoVF-kEs_uAO0-7gZ4Rv6rzdu90z9yxDuItjmf4-XG6PQe830n65/s320/prestosuchus.jpg" width="320" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
<i>Prestosuchus</i> threatening an <i>Eoraptor</i> in the "Ultimate
Dinosaurs" exhibition at the Science Museum of Minnesota, May 2014.<br />
</td>
</tr>
</tbody>
</table>
<p><span></span></p><a name='more'></a><p></p><p>Now, the yearly roundup: Again there were 78 updates since our last check-in,
on
<a href="https://equatorialminnesota.blogspot.com/2022/10/compact-thescelosaurus-year-seven.html" rel="nofollow" target="_blank">October 9, 2022</a>. Of these, on the credit side there were 57 new species, 3 overlooked
species, 1 moved to a new genus, and 1 added after further consideration. On
the other hand, 9 previously established species were sunk, making this our
busiest year for synonymizations. The flow of updates was fairly constant,
with lows in October, December, March, and April, a high in November, and a
head of steam building since about May. The headline group, Dinosauria, took
it on the chin most of the year, with practically all of the new names coming
over a couple of weeks in November, a couple of weeks in June, a week in July,
and a week in September. Subtracting two sauropods that had been previously
overlooked, I'm mildly surprised to find that this period matched the previous
for dinosaurs, 28 to 28, but it's not 2023's doing; 10 of the 28 came in the
last three months of 2022. Go figure.
</p>
<p>
Chronologically, of the 57 new species, 11 were Triassic (2 Early, 1 Middle, 1
Middle or Late, and 7 Late). 10 were plain Jurassic (1 Early, 1 Middle, 2
Middle or Late, and 6 Late), and there were 2 Late Jurassic or Early
Cretaceous. As usual, the Cretaceous came off the best, with 34 (10 Early and
24 Late). I keep adding Triassic groups but it doesn't seem to inspire them.
</p>
<p>
Geographically, 17 names came from Asia (omitting India as doing its own thing
in the Mesozoic, 13 came from Europe, 12 came from North America, 7 came from
South America, 4 came from Africa (omitting Madagascar), 3 came from India,
and 1 came from Madagascar. Country-wise the distribution tailed off quickly
after China (12) and the United States (10). Spain was the surprise third
place with 5, then Argentina, Brazil, Germany, and India tied with 3, and
several others had 2 (Egypt, Kazakhstan, Morocco, Portugal, United Kingdom) or
1 (Canada, Chile, Denmark [Greenland], Japan, Madagascar, Mongolia, Romania,
and Thailand). Several usual competitors turned in low figures (Argentina,
Brazil, Canada, Mongolia, the UK).
</p>
<p>Taxonomically, we had:</p>
<p>
2 new aetosaur species:<br /><i>Kryphioparma caerula<br />Venkatasuchus armatum</i><br />
</p>
<p>
3 new basal avemetatarsalian species:<br /><i>Amanasaurus nesbitti<br />Mambachiton fiandohana<br />Venetoraptor
gassenae</i><br />
</p>
<p>
3 new ichthyosaur species:<br /><i>Eurhinosaurus quenstedi<br />Nannopterygius mikhailovi<br />Nannopterygius
yakimenkae</i><br />
</p>
<p>
6 new mosasauroid species:<br /><i>Carentonosaurus algorensis<br />Carentonosaurus soarensis<br /></i>"Hainosaurus"
<i>boubker<br />Halisaurus hebae<br />Sabarosaurus dahli<br />Stelladens
mysteriosus<br /></i>A pretty good year for mosasauroids, all told.<br />
</p>
<p>
3 new phytosaur species:<br /><i>Colossosuchus techniensis<br />Jupijkam paleofluvialis<br />Mystriosuchus
alleroq</i><br />
</p>
<p>
3 new plesiosaur species:<br /><i>Chubutinectes carmeloi<br />Plesioelasmosaurus walkeri<br />Styxosaurus
rezaci</i><br />
</p>
<p>
5 new pterosaur species:<br /><i>Balaenognathus maeuseri<br />Eopteranodon yixianensis<br />Lusognathus
almadrava<br />Petrodactyle wellnhoferi<br />Shenzhoupterus sanyainus</i><br />
</p>
<p>
4 new basal sauropterygian species:<br /><i>Chusaurus xiangensis<br />Luopingosaurus imparilis<br />Prosaurosphargis
yingzishanensis<br />Wumengosaurus rotundicarpus</i><br />
</p>
<p>
7 new theropod species (classic dinosaurs only):<br /><i>Daspletosaurus wilsoni<br />Daurlong wangi<br />Fujianvenator
prodigiosus<br />Migmanychion laiyang<br />Natovenator polydontus<br />Protathlitis
cintorrensis<br />Tyrannomimus fukuiensis<br /></i>The diversity was all right if you like coelurosaurs; otherwise October 2022
to October 2023 was probably not exciting.
</p>
<p>
8 new sauropod species:<br /><i><a href="https://equatorialminnesota.blogspot.com/2022/11/your-friends-titanosaurs-caieiria-allocaudata.html" rel="nofollow" target="_blank">Caieiria allocaudata</a><br /><a href="https://equatorialminnesota.blogspot.com/2023/02/your-friends-titanosaurs-chucarosaurus-ruixinia.html" rel="nofollow" target="_blank">Chucarosaurus diripienda</a><br />Garumbatitan morellensis<br /><a href="https://equatorialminnesota.blogspot.com/2023/07/your-friends-titanosaurs-igai-semkhu.html" rel="nofollow" target="_blank">Igai semkhu</a><br /><a href="https://equatorialminnesota.blogspot.com/2023/09/your-friends-titanosaurs-jiangxititan.html" rel="nofollow" target="_blank">Jiangxititan ganzhouensis</a><br /><a href="https://equatorialminnesota.blogspot.com/2023/02/your-friends-titanosaurs-chucarosaurus-ruixinia.html" rel="nofollow" target="_blank">Ruixinia zhangi</a><br />Tharosaurus indicus<br />Yuzhoulong qurenensis<br /></i>Again, the diversity was great if you like somphospondylans, otherwise
not.<br />
</p>
<p>
2 new thyreophoran species:<br /><i>Patagopelta cristata<br /><a href="https://equatorialminnesota.blogspot.com/2023/06/vectipelta-barretti.html" rel="nofollow" target="_blank">Vectipelta barretti</a></i><br />
</p>
<p>
1 new nebulous neornithischian species:<br /><i>Minimocursor phunoiensis</i><br />
</p>
<p>
2 new marginocephalian species:<br /><i>Furcatoceraops elucidens<br />Platytholus clemensi</i><br />
</p>
<p>
8 new ornithopod species:<br /><i>Calvarius rapidus<br /><a href="https://equatorialminnesota.blogspot.com/2023/06/gonkoken-nanoi.html" rel="nofollow" target="_blank">Gonkoken nanoi</a><br />Iani smithi<br />Malefica deckerti<br />Nevadadromeus schmitti<br />Oblitosaurus
bunnueli<br />Transylvanosaurus platycephalus<br />Vectidromeus insularis<br /></i>It was a good year for ornithopods that weren't hadrosaurids.
</p>
<p>
1 species was transferred to a new genus:<br /><i>Huaxiapterus corollatus</i>
to <i>Huaxiadraco</i><br />
</p>
<p>
1 species was added upon further review:<br /><i>Galtonia gibbidens</i> (to
the aetosaur tab)<br />
</p>
<p>
3 previously overlooked species were recognized:<br /><i>Bashunosaurus kaijiangensis</i>
(from 2004)<br /><i>Trematospondylus macrocephalus</i> (overlooked by almost
everyone since 1858!)<br />"Shunosaurus" <i>jiangyiensis</i> (from 2004)<br />
</p>
<p>
9 species were sunk:<br /><i>Gravitholus albertae</i> into
<i>Stegoceras validum<br />Hansuessia sternbergi</i> into
<i>Stegoceras validum<br />Huaxiapterus atavismus</i> into
<i>Sinopterus dongi<br />Huaxiapterus benxiensis</i> into
<i>Huaxiadraco corollatus<br />Huaxiapterus jii</i> into
<i>Sinopterus dongi</i><br /><i>Sinopterus hui</i> into
<i>Sinopterus dongi<br />Sinopterus lingyuanensis</i> into...
<i>Sinopterus dongi</i> (what a twist!)<br /><i>Onychosaurus hungaricus</i>
into
<i>Zalmoxes robustus<br /><a href="https://equatorialminnesota.blogspot.com/2022/11/your-friends-titanosaurs-caieiria-allocaudata.html" rel="nofollow" target="_blank">Trigonosaurus pricei</a></i><a href="https://equatorialminnesota.blogspot.com/2022/11/your-friends-titanosaurs-caieiria-allocaudata.html" rel="nofollow" target="_blank">
into <i>Baurutitan britoi</i></a><br />
</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-12194150436639743452023-09-28T22:46:00.001-05:002023-09-28T22:46:55.170-05:00Your Friends The Titanosaurs: Jiangxititan ganzhouensis<p>It's that time again, when another titanosaur makes an introduction. Today we have <i>Jiangxititan ganzhouensis</i>, from the late Late Cretaceous of southeastern China. As a disclaimer, I tend to reserve my judgment with East Asian titanosauriforms, who have a tendency to play coy about their phylogenetic relationships. However, <i>J. ganzhouensis</i> is interesting on its own terms, whether or not it is within that charmed circle of "<a href="https://equatorialminnesota.blogspot.com/2018/08/your-friends-titanosaurs-3-andesaurus-antarctosaurus-argentinosaurus.html" rel="nofollow" target="_blank"><i>Andesaurus delgadoi</i></a> + <i><a href="https://equatorialminnesota.blogspot.com/2020/07/your-friends-titanosaurs-27-ruyangosaurus-saltasaurus-sarmientosaurus.html" rel="nofollow" target="_blank">Saltasaurus loricatus</a></i>".</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhH3Ie6KornY_922ZeF7KGu49NW0PQjkB_Gx5KSRkqRpWwQraekvzXweQ-MbdkpGtb5ww61BSbKELZJwiofFKj4TqRJlMefKe6etWLPqlOFQXiSYv4lkZMcaMslRvg8ZwRZIHKiJg5yS8fyz1Ksc3C27hwD4KrAFBmZcTF1siJDPVI1vnYa9yGjv0Qsm_WF/s2008/jiangxititan_verts_lateral_fig_3.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1468" data-original-width="2008" height="293" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhH3Ie6KornY_922ZeF7KGu49NW0PQjkB_Gx5KSRkqRpWwQraekvzXweQ-MbdkpGtb5ww61BSbKELZJwiofFKj4TqRJlMefKe6etWLPqlOFQXiSYv4lkZMcaMslRvg8ZwRZIHKiJg5yS8fyz1Ksc3C27hwD4KrAFBmZcTF1siJDPVI1vnYa9yGjv0Qsm_WF/w400-h293/jiangxititan_verts_lateral_fig_3.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A lateral view of the type vertebrae of <i>Jiangxititan ganzhouensis</i>, dorsals on left, cervicals on right; scale is 20 cm (8 in) (Figure 3, <a href="https://www.tandfonline.com/doi/full/10.1080/08912963.2023.2259413" rel="nofollow" target="_blank">Mo et al. 2023</a>, which see for legend) (<a href="https://creativecommons.org/licenses/by-nc-nd/4.0/" rel="nofollow">CC BY-NC-ND-4.0</a>).</td></tr></tbody></table><p></p><span><a name='more'></a></span><p></p><p><u>Genus and Species</u>: <i>Jiangxititan ganzhouensis</i>. The genus name refers to Jiangxi Province and the species name refers to Ganzhou City, the fossil locality (Mo et al. 2023). This leads to something like "Jiangxi titan from Ganzhou City". A digression: Anybody else notice that Chinese dinosaur names are very frequently geographic in origin, rather than mythological, anatomical, or honorific?</p><p><u>Citation</u>: Mo, J.-Y., Q.-Y. Fu, Y.-L. Yu, and X. Xu. 2023. <a href="https://www.tandfonline.com/doi/full/10.1080/08912963.2023.2259413" rel="nofollow" target="_blank">A new titanosaurian sauropod from the Upper Cretaceous of Jiangxi Province, southern China</a>. Historical Biology (advance online publication). doi: <a href="https://doi.org/10.1080/08912963.2023.2259413" rel="nofollow" target="_blank">https:10.1080/08912963.2023.2259413</a>.<br /></p><p></p><p><u>Geography and Stratigraphy</u>: The type and only known specimen came from the Maastrichtian-age Nanxiong Formation of Tankou Town, Nankang County, Ganzhou City, Jiangxi Province, southeastern China (Mo et al. 2023).<br /></p><p><u>Holotype</u>: NHMG 034062 (Natural History Museum of Guangxi Zhuang Autonomous Region, Nanning, China), 12 articulated bones from the base of the neck (three <a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow" target="_blank">posterior</a> <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow" target="_blank">cervicals</a>, four anterior dorsals, two cervical ribs, and three dorsal ribs) (Mo et al. 2023).<br /></p><p><i>J. ganzhouensis</i> has a frustrating holotype. There are seven articulated vertebrae with attached partial ribs, enough associated material (and in good enough shape) to prompt the question "well, where's the rest of it?". It just <i>looks</i> like there should be more; it <i>can't</i> just be a chunk of the base of the neck, can it? (Unfortunately, yes, it can.) The authors do not go into detail on the circumstances of discovery, except to note it was recovered during construction work; we can always hope that another part of the skeleton is waiting to be discovered nearby.</p><p>It's kind of a cliché that titanosaurs are known from vertebrae and nothing else. In this case, the cliché mostly fits, but <i>J. ganzhouensis</i> goes out of its way to make a memorable impression. The centra are vertically compressed to an almost comical degree, but this does not appear to be primarily taphonomic (there is some taphonomic deviltry going on, but it mostly affects the left side). The neural spines are divided, as in <i><a href="https://equatorialminnesota.blogspot.com/2020/02/your-friends-titanosaurs-21-nullotitan-opisthocoelicaudia-overosaurus.html" rel="nofollow" target="_blank">Opisthocoelicaudia skarzynskii</a></i>, but the spread of the division is extreme, with the spines very low rather than sticking up; the visual effect is as if <i>J. ganzhouensis</i> had made space to stack another vertebral column in the bifurcation. The spines are inclined anteriorly on the cervicals but vertically to slightly posteriorly on the dorsals. The neural arches are low, and features that would normally be placed facing dorsally and laterally just face laterally here. The one relatively complete dorsal rib appears to relatively short and slender (Mo et al. 2023). Comparison of vertebral sizes with <i>O. skarzynskii</i> indicates <i>J. ganzhouensis</i> was in the same general bracket (provided the rest of it wasn't radically different).</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgICt2U9N6Bpd0uwBbaVQc7cpdBpHx_kpGQIee_c8wtgVzOuW3rcnNvNWVCdmvy24UT6xOO_0fejG2M5FYG_2vgTrCWQQvKGYIqDmXHMvOp8BMZ8enzdj7IFzhMsz7Gc9_oco2ecBXuhsY04OZ0-k1Tue0cIqjl9FM4vhl5n1KFXWPEDXcPgZW988EgA__7/s1500/jiangxititan_centra_fig_11.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="942" data-original-width="1500" height="251" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgICt2U9N6Bpd0uwBbaVQc7cpdBpHx_kpGQIee_c8wtgVzOuW3rcnNvNWVCdmvy24UT6xOO_0fejG2M5FYG_2vgTrCWQQvKGYIqDmXHMvOp8BMZ8enzdj7IFzhMsz7Gc9_oco2ecBXuhsY04OZ0-k1Tue0cIqjl9FM4vhl5n1KFXWPEDXcPgZW988EgA__7/w400-h251/jiangxititan_centra_fig_11.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">How low can you go? An anterior dorsal of <i>J. ganzhouensis</i> (F) compared to <i>Opisthocoelicaudia</i> (A), <i>Camarasaurus</i> (B), <i>Apatosaurus</i> (C), <i>Diplodocus</i> (D), and <i>Dicraeosaurus</i> (E); scale 20 cm (8 in) (Figure 11 in Mo et al. 2023) (<a href="https://creativecommons.org/licenses/by-nc-nd/4.0/" rel="nofollow">CC BY-NC-ND-4.0</a>).</td></tr></tbody></table><p></p><p>We can proceed with confidence that <i>J. ganzhouensis</i> is not going to be mistaken for any other known sauropod represented by posterior cervicals or anterior dorsals. What exactly was it? The phylogenetic analysis of Mo et al. (2023) places it deep within Lognkosauria with its new best friend <i><a href="https://equatorialminnesota.blogspot.com/2021/03/your-friends-titanosaurs-34-yesterday.html" rel="nofollow" target="_blank">Mongolosaurus haplodon</a></i>. Both of these are interesting points because Lognkosauria is famously a club for large South American titanosaurs and <i>M. haplodon</i> has a long history of shunning commitment. (<a href="https://en.wikipedia.org/wiki/Gannansaurus" rel="nofollow" target="_blank"><i>Gannansaurus sinensis</i></a>, from the same formation as <i>J. ganzhouensis</i>, also makes a guest appearance and remains firmly outside of Titanosauria, persisting as a rare late Late Cretaceous non-titanosaur.) Whether it remains in Titanosauria or gravitates out like various other putative East Asian titanosaurs, <i>J. ganzhouensis</i> will retain those distinctive vertebrae.<br /></p><p></p><p>References</p><p>Mo, J.-Y., Q.-Y. Fu, Y.-L. Yu, and X. Xu. 2023. <a href="https://www.tandfonline.com/doi/full/10.1080/08912963.2023.2259413" rel="nofollow" target="_blank">A new titanosaurian sauropod from the Upper Cretaceous of Jiangxi Province, southern China</a>. Historical Biology (advance online publication). doi: <a href="https://doi.org/10.1080/08912963.2023.2259413" rel="nofollow" target="_blank">https:10.1080/08912963.2023.2259413</a>.</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com1tag:blogger.com,1999:blog-6574000839639433662.post-61067069559767487052023-09-14T20:49:00.000-05:002023-09-14T20:49:55.716-05:00Fossils of the Upper Ordovician Platteville Formation in the Upper Midwest USA: An Overview<p>I'm not really in the business of plugging books, but I *have* gotten one recently that those of you who read this blog for the Ordovician posts may find interesting (if you haven't already come across it). The book is "Fossils of the Upper Ordovician Platteville Formation in the Upper Midwest USA: An Overview" by Dennis Kolata, Illinois State Geological Survey emeritus (and also one of the authors on a volume on the <a href="https://equatorialminnesota.blogspot.com/2016/07/former-ash-beds-in-st-paul.html" rel="nofollow" target="_blank">Deicke K-bentonite</a>). I was tipped off to it by member "connorp" on The Fossil Forum during my quest to identify what turned out to be <i><a href="https://equatorialminnesota.blogspot.com/2023/08/zittelloceras.html" rel="nofollow" target="_blank">Zittelloceras</a></i>.</p><p></p><p>The Platteville of Illinois and southern Wisconsin isn't *exactly* the same as in Minnesota (the strata are thicker and the fossils are better preserved than what we see in the Twin Cities), but anyone looking for information or comparative photos for Minnesota Platteville fossils is going to find plenty in the book to consider. The book is also useful for identifying fossils in the overlying rocks (e.g., the Decorah Shale), because many of the genera are the same. Several graphics clarify the correlation of different Platteville divisions across the area where the formation was deposited.</p><p>The text, organized by broad taxonomic group, is technical. Each species is given a diagnosis, followed by remarks about aspects such as notable features or distinguishing it from other species, and then its stratigraphic and geographic distribution. This is not unlike the various group-focused articles in Sloan (1987), but unlike the small black-and-white figures in the 1987 book, Kolata's book is filled with gorgeous color plates featuring large photos of every species. (The one quibble I have is that scaling is given by numbers, e.g., "x1.5", instead of scale bars, but I can certainly use them either way!) For anyone who is interested in the fossils but is not versed in the details of invertebrate anatomy, or anyone just looking to identify a particular find, these plates are invaluable.<br /></p><p>If you'd like to find out more about this volume, the Illinois State Geological Survey bookstore is online <a href="https://shop.inrs.illinois.edu/isgs-books.html" rel="nofollow" target="_blank">here</a>. The book can also be found <a href="https://www.amazon.com/Fossils-Ordovician-Platteville-Formation-Midwest/dp/0578911752" rel="nofollow" target="_blank">on Amazon</a>. It is 316 pages and costs $60.00.<br /></p><p>References</p><p>Kolata, D. R. 2021. Fossils of the Upper Ordovician Platteville Formation in the upper Midwest USA: an overview. Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois. Bulletin 108.</p><p>Sloan, R. E., editor. 1987.
<a href="https://hdl.handle.net/11299/60756" rel="nofollow" target="_blank">Middle and Late Ordovician lithostratigraphy and biostratigraphy of the
Upper Mississippi Valley</a>. Minnesota Geological Survey, St. Paul, Minnesota. Report of Investigations
35.</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-42976710045804562272023-08-31T20:20:00.000-05:002023-08-31T20:20:35.758-05:00Fossil Collections of the Ancestral Puebloans<p>Although the ancient biological origin of fossils has only been widely appreciated in the past couple hundred years, people have collected fossils for various reasons for millennia. One of my favorite instances is recorded by Roman biographer Suetonius, who noted that Augustus had a collection of bones of "sea and land monsters" at Capri. (By the way, if you're also a sucker for ancient history as written by ancient historians, "The Twelve Caesars" is a great book.)</p><p>One of the things I've come across working with National Park Service paleontology is that the <a href="https://en.wikipedia.org/wiki/Ancestral_Puebloans" rel="nofollow" target="_blank">Ancestral Puebloans</a>, represented by <a href="https://en.wikipedia.org/wiki/List_of_Ancestral_Puebloan_dwellings_in_Arizona" rel="nofollow" target="_blank">numerous</a> <a href="https://en.wikipedia.org/wiki/List_of_Ancestral_Puebloan_dwellings_in_Colorado" rel="nofollow">locations</a> <a href="https://en.wikipedia.org/wiki/List_of_Ancestral_Puebloan_dwellings_in_New_Mexico" rel="nofollow" target="_blank">in the</a> <a href="https://en.wikipedia.org/wiki/List_of_Ancestral_Puebloan_dwellings_in_Utah" rel="nofollow" target="_blank">NPS</a>, had a notable interest in fossils. This is something that took a while for me to realize because most of the evidence is in the archeological literature and as a paleontologist, I didn't know to look in it. On the flip side, the archeologists generally didn't make a big deal of finding run-of-the-mill fossils among the artifacts at their sites; for them, fossils were just one class of objects among many. I haven't made an exhaustive survey, but a couple of sites stand out.</p><p>Pecos Pueblo is the namesake feature of the complex <a href="https://www.nps.gov/peco/index.htm" rel="nofollow" target="_blank">Pecos National Historical Park</a>. The pueblo was excavated between 1915 and 1925 by Alfred Vincent Kidder of the Robert S. Peabody Museum of Archaeology (Phillips Academy, Andover, Massachusetts). Kidder (1932) reported finding "many hundreds" of fossils at Pecos Pueblo. They were predominantly marine fossils from "the limestone formations underlying the red sandstones of the valley", which appears to correspond to the Pennsylvanian-age Alamitos Formation of the Madera Group. Among these were corals, brachiopods ("bivalves" of the photo caption), snails, and crinoids. Not all were marine; among them was a partial rhino tooth, and there were also many pieces of petrified wood, including colorful Chinle wood and brown or gray wood typical of the area southwest of Santa Fe, possibly selected for its unusual cleavage and the "clear, resonant tone which it gives when tapped". Kidder observed that the majority of the fossils were found in rubbish and suggested they were collected as curios, but I have to wonder. It takes some effort to collect hundreds of fossils (although admittedly Pecos Pueblo was inhabited for a long time).<br /></p><p>Pecos Pueblo is hardly a patch on <a href="https://en.wikipedia.org/wiki/Pueblo_Bonito" rel="nofollow" target="_blank">Pueblo Bonito</a> of <a href="https://www.nps.gov/chcu/index.htm" rel="nofollow" target="_blank">Chaco Culture National Historical Park</a>, though. Pepper (1920) documented fossils in 18 rooms, not counting artifacts made of petrified wood. Most had just a few, but Room 12 is something else. Room 12 has a floor area less than 10 square meters (108 square feet; a bit less than 3.7 by 2.7 m or 12 ft by 9 ft), and when excavated contained a 1.5 m (5 ft) thick layer including the following:<br /></p><ul style="text-align: left;"><li>1,000+ small fossil shells</li><li>300 fragments of crinoid stems</li><li>140+ water-worn pebbles</li><li>125+ chalcedony concretions</li><li>125+ fragments of contemporary Pacific shells</li><li>50 to 75 specimens of crystals or other rocks and minerals of beauty or interesting form </li></ul><p>This is the largest intentional accumulation of fossils predating the rise of museums that I've come across. Furthermore, unlike Pecos Pueblo, a significant chunk of the paleontological collection could not have been collected more or less "in the backyard". Judd (1954) provided taxonomic identifications of some of the fossils from a re-excavation. Chaco Canyon is over Campanian (Late Cretaceous) bedrock. The taxa identified from Room 12 include several Pennsylvanian-age brachiopod species known from central New Mexico, a Cenomanian ammonite (<i>Metoicoceras whitei</i>) with its nearest occurrences in the Black Mesa area of Arizona, and a snail (<i>Gyrodes compressa</i>/<i>Euspira compressa</i>) known from Upper Cretaceous rocks of the Pacific coast of California. This is a gathering of fossils that took some effort.</p><p>What exactly were the inhabitants of Pueblo Bonito doing with 1,300+ fossils? Agostini and Notterpek (2020) suggest that the fossil shells, together with the water-worn pebbles and concretions, were symbolic of water and a "past watery world". The canyon itself would also be symbolic of the action of water. It's an interesting idea, although again I do marvel at the sheer number of fossils. The scientific romantic in me wonders if there was someone there who just found fossils and minerals interesting, maybe even had them arranged in some pleasing setup (even sorted by morphology), and perhaps cultivated the collection of rare and unfamiliar objects. Or, maybe concentrating all of those fossils in one small place amplified their power. Or, maybe it <i>was</i> something like a museum, or at least a place to display and contemplate these objects. But what do I know?<br /></p><p>References</p><p>Agostini, M. R., and I. Notterpek. 2020. Cosmological expressions and medicine stones in the Ancestral Pueblo world. KIVA 86:(4):4030–427. doi: <a href="https://doi.org/10.1080/00231940.2020.1832406" rel="nofollow" target="_blank">https://doi.org/10.1080/00231940.2020.1832406</a>.<br /></p><p>Judd, N. M. 1954. <a href="https://repository.si.edu/handle/10088/22905" rel="nofollow" target="_blank">The material culture of Pueblo Bonito</a>. Smithsonian Miscellaneous Collections 124.<br /></p><p>Kidder, A. V. 1932. The artifacts of Pecos. Yale University Press, New Haven, Connecticut.</p><p>Pepper, G. H. 1920. <a href="https://digitallibrary.amnh.org/handle/2246/105" rel="nofollow" target="_blank">Pueblo Bonito</a> [large file]. Anthropological Papers of the American Museum of Natural History 27.</p><p>G. Suetonius Tranquillus. 121. The twelve Caesars. Penguin Books, London, England. 1989 reprint of 1957 translation by Robert Graves.<br /></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-32502275988098883312023-08-13T15:02:00.000-05:002023-08-13T15:02:24.465-05:00Zittelloceras<p>
While on a walk earlier this year, I spotted a Decorah block that I decided to
pick up for photography. The initial attraction was the abundance of snails,
which are a reliable indicator that pieces of our
<a href="https://equatorialminnesota.blogspot.com/2018/08/lower-decorah-trilobites.html" rel="nofollow" target="_blank">fossil arthropod friends</a>
are also present (if there's only one practical thing you take away from this
blog, it's "when you're in the Decorah and see snails, look for trilobites").
This was indeed the case:
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
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<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibJskC-lsJXACLoUj5MU3uu0pW4hjOPkFonA1wfwR9Odi9nojezWBI-esQVyTSllfYvGmGHpJhfmCccPcaIT_VnavTXoRSz4aozHI7gz1KbRxzt_oJmIq_sxSapDElv4h1m5zrQT246xwb_WHRGx4MMJkroGB-C4F4PSdn6CU6NWxTd-KufoVhJ17JvOkv/s3975/IMG_0333_crop.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2783" data-original-width="3975" height="280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibJskC-lsJXACLoUj5MU3uu0pW4hjOPkFonA1wfwR9Odi9nojezWBI-esQVyTSllfYvGmGHpJhfmCccPcaIT_VnavTXoRSz4aozHI7gz1KbRxzt_oJmIq_sxSapDElv4h1m5zrQT246xwb_WHRGx4MMJkroGB-C4F4PSdn6CU6NWxTd-KufoVhJ17JvOkv/w400-h280/IMG_0333_crop.jpg" width="400" /></a>
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<td class="tr-caption" style="text-align: center;">
Here's the whole block, which rewards a click to embiggen. There is a
nice
<a href="https://equatorialminnesota.blogspot.com/2018/11/decorah-gastropods.html" rel="nofollow" target="_blank"><i>Clathrospira</i> and a lophospire</a>
just right of the scale bar, and many smaller snails scattered
throughout. You may also pick out the trilobite pygidia.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG2qVNcdatZMOgvXu_FAeIbvzZGptG-rWH8WHY_p7WBFtqWU5LliuFwgmoU_rqqsb-QI4YMXsg3Xl7QQj9QyQ5r3Aks9iThFqgZvQLYCO9APzp3--H3PoRMcIT05YqCPl2djtF_iGC76_IfFmEs3Q6a_5aEXtAm9oPaqKzdJEZI56SKMbTqcnUMgND-cyq/s1560/pygidium_crop_1.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1251" data-original-width="1560" height="321" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG2qVNcdatZMOgvXu_FAeIbvzZGptG-rWH8WHY_p7WBFtqWU5LliuFwgmoU_rqqsb-QI4YMXsg3Xl7QQj9QyQ5r3Aks9iThFqgZvQLYCO9APzp3--H3PoRMcIT05YqCPl2djtF_iGC76_IfFmEs3Q6a_5aEXtAm9oPaqKzdJEZI56SKMbTqcnUMgND-cyq/w400-h321/pygidium_crop_1.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Here's a pygidium, pointed toward the top of the photo.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggGn3rLWiuMe2v-xfW4LCNVUzhilHv1tQLkD-JObIrC_RAuKpwYJYEzIgnIpmkw3TLMl7JO8D2tZSeZ_cNmbziFffan_a4w8KG8Q_geW6xJxjTUAFtPaQiQYL-OLKMGvRRM7mTVk2xyock7VR1t1EI9_RuD--a-BQDo6zojTevyBooiBu0u_ucYnMR7jiA/s1925/pygidium_crop_2.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1623" data-original-width="1925" height="338" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggGn3rLWiuMe2v-xfW4LCNVUzhilHv1tQLkD-JObIrC_RAuKpwYJYEzIgnIpmkw3TLMl7JO8D2tZSeZ_cNmbziFffan_a4w8KG8Q_geW6xJxjTUAFtPaQiQYL-OLKMGvRRM7mTVk2xyock7VR1t1EI9_RuD--a-BQDo6zojTevyBooiBu0u_ucYnMR7jiA/w400-h338/pygidium_crop_2.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A nice pygidium plus a number of other things, including some crinoid columnals, bryozoan fragments, other trilobite bits, and, near the top, a whorl of a snail.<br /></td></tr></tbody></table>
<p>There was also something else: a dark object several millimeters long and
broad. It appeared to be a thin-walled flattened tubular object, with a
distinct series of ornamented transverse ridges. The ridges showed an
alternating pattern of strongly projecting and more subtle, like perforations.
Both had little scooped frilling, the same kind of shape as a doodle of
stereotypical ocean waves.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxs5KH6qkWHDNAWS4bEu5kQjRRTvav9vNhOwcGgBTMTMoOqpTFNo1fMvgnS1KVD1Xui1txqRiA1JQkFmswM9leZLjZrBLLn-j9SROLznci7ZPq8ULj1BkVNYLCFSNjs6xrEcC1cVtYWEcOF-8mfM2v374xf9dC9Tt0T-u2H7G0dgjrpPpUBx-TfK6elPUE/s2594/zittelloceras_crop_1.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2124" data-original-width="2594" height="328" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxs5KH6qkWHDNAWS4bEu5kQjRRTvav9vNhOwcGgBTMTMoOqpTFNo1fMvgnS1KVD1Xui1txqRiA1JQkFmswM9leZLjZrBLLn-j9SROLznci7ZPq8ULj1BkVNYLCFSNjs6xrEcC1cVtYWEcOF-8mfM2v374xf9dC9Tt0T-u2H7G0dgjrpPpUBx-TfK6elPUE/w400-h328/zittelloceras_crop_1.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The object in question is near center. You may have noticed it in the first photo. The light-colored band near the center is some light prep to see if I could get the matrix out from the groove.<br /></td></tr></tbody></table><p></p>
<p>
I'd never seen this combination of features before, but I could knock out a
lot of things quickly. In fact, I knocked out just about everything, which was
a problem. Given the probability I had discovered a completely new phylum is
pretty low, all things considered, I figured I'd probably missed something.
So, I pulled out my copy of "A Sea Without Fish" (Meyer and Davis 2009) to see
if some similar exotica had been found in the well-studied Cincinnatian, as
it's only a few million years younger. Then I got excited looking at the
figure and description of the
<a href="https://en.wikipedia.org/wiki/Machaeridia_(annelid)" rel="nofollow" target="_blank">machaeridian</a>
worm <i>Lepidocoleus</i>. Machaeridia is an extinct group of Paleozoic armored
annelid worms, with segments of calcitic plates and a heart-shaped
cross-section.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifckbptwkfAYWO6jib8w9QZmWmmu9HePgYkvyOwWZvkMgiXOQ6VuMgSrZFYqV6mCJHEpIW6GcK7KGQrDddvDCtYp-IpJ-lzp6LKe2cHQwbWLhtKyzfCP2thyWt4MIuFIzYDVCoOhhwwgyML7zHe7O9Ma5DyPrIAPBiBPo28tCWWxTNTsgn6pyn6Wd1U7UQ/s2536/zittelloceras_crop_2.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2234" data-original-width="2536" height="353" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifckbptwkfAYWO6jib8w9QZmWmmu9HePgYkvyOwWZvkMgiXOQ6VuMgSrZFYqV6mCJHEpIW6GcK7KGQrDddvDCtYp-IpJ-lzp6LKe2cHQwbWLhtKyzfCP2thyWt4MIuFIzYDVCoOhhwwgyML7zHe7O9Ma5DyPrIAPBiBPo28tCWWxTNTsgn6pyn6Wd1U7UQ/w400-h353/zittelloceras_crop_2.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">This view, under different lighting, shows the ridges and frills to good effect.<br /></td></tr></tbody></table><p></p>
<p>
Before I got too excited, I decided to
<a href="http://www.thefossilforum.com/index.php?/topic/133767-decorah-shale-enigma/" rel="nofollow" target="_blank">put it up</a>
on the Fossil Forum, to see what others might think. The first suggestion was
<i><a href="https://equatorialminnesota.blogspot.com/2020/02/phragmolites.html" rel="nofollow" target="_blank">Phragmolites</a></i>, which was reasonable enough but didn't fit my experience with that snail.
The chunk wasn't curved enough, the dark coloration and thin wall were unlike
the examples of <i>Phragmolites</i> I'd seen, and the ornamentation of the
ridges wasn't a good fit. Then someone came up with the nautiloid
<i>Zittelloceras</i>, and provided photos of a form with almost the exact same
pattern of frilled ridges found in the Platteville.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-m74QpcmXg-pP5G-bfeoywkKAQrxZ5hwqwPITB1qcrIWHyoLkGMguotpzuwhJRtvYkxxr_Fm3CFaMATHX_hqSn6bfEMB2POgA1Tyo4ZwQ4Yd_GYByAc-krTkBQESFE4crS4ESoK56Pdayy4dxOrgT4pKZFy77mo6Vr78Z-6a2kTXQ5neyQneiiobRrVpI/s2573/zittelloceras_crop_3.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1498" data-original-width="2573" height="233" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-m74QpcmXg-pP5G-bfeoywkKAQrxZ5hwqwPITB1qcrIWHyoLkGMguotpzuwhJRtvYkxxr_Fm3CFaMATHX_hqSn6bfEMB2POgA1Tyo4ZwQ4Yd_GYByAc-krTkBQESFE4crS4ESoK56Pdayy4dxOrgT4pKZFy77mo6Vr78Z-6a2kTXQ5neyQneiiobRrVpI/w400-h233/zittelloceras_crop_3.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">An end-on view shows the cross-section, with the thin walls and central crushing.<br /></td></tr></tbody></table><p></p>
<p>
So, it looks like rather than a worm, it's a nautiloid.
<i>Zittelloceras</i> is one of the "arched" nautiloids, not coiled and not a
full-on orthocone. Several species are present in the Platteville per Catalani
(1987), but none are listed in the Decorah. This is not a particular problem,
as the genus is present in younger strata as well, and the Decorah's
cephalopod record lags the Platteville. (Note that <i>Zittelloceras</i> is
frequently misspelled "<i>Zitteloceras</i>", with one "l", but a look at the
original publication, Hyatt 1884, shows the
<a href="https://www.biodiversitylibrary.org/page/42025375" rel="nofollow" target="_blank">two-l spelling is correct</a>.) I'm sure there are worms out there to be found in the Decorah, but I'll
settle for this record of an ornate nautiloid.</p><p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4bovBaEtX1VYpvbqJYwoXdTz9BXfbqOLDD2YejVo1hrY89f3-rTBhwxk0hA5d2PM7JdZiTMnqNhloBhCKaY1d6luzSvJANusZVuTfd8_cpIB-7FaQimdtDA5smopCotqJ1-zaEn36t6o9OqMNpxKOHWFFUrB3pO_KpLFm_qYdEFiS-jrsfJ_7QgKkam1V/s1989/zittelloceras_crop_4.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1590" data-original-width="1989" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4bovBaEtX1VYpvbqJYwoXdTz9BXfbqOLDD2YejVo1hrY89f3-rTBhwxk0hA5d2PM7JdZiTMnqNhloBhCKaY1d6luzSvJANusZVuTfd8_cpIB-7FaQimdtDA5smopCotqJ1-zaEn36t6o9OqMNpxKOHWFFUrB3pO_KpLFm_qYdEFiS-jrsfJ_7QgKkam1V/w400-h320/zittelloceras_crop_4.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Here's one more angle for the road.<br /></td></tr></tbody></table></p>
<p>References</p>
<p>
Catalani, J. A. 1987. Biostratigraphy of the Middle and Late Ordovician
cephalopods of the Upper Mississippi Valley area. Pages 187–189 <i>in </i>R.
E. Sloan, editor.
<a href="https://hdl.handle.net/11299/60756" rel="nofollow" target="_blank">Middle and Late Ordovician lithostratigraphy and biostratigraphy of the
Upper Mississippi Valley</a>. Minnesota Geological Survey, St. Paul, Minnesota. Report of Investigations
35.
</p>
<p>
Hyatt, A. 1884.
<a href="https://www.biodiversitylibrary.org/page/42025344" rel="nofollow" target="_blank">Genera of fossil cephalopods</a>. Proceedings of the Boston Society of Natural History 22:253–338. [some
history: The paper is based on a talk presented by Hyatt April 4, 1883, a day
before his birthday. There is a note on the first page that there was going to
be a monograph in the Memoirs of the Museum of Comparative Zoology, but this
did not happen. At any rate it's hard to think of an 80-page paper being
"preliminary" to anything!]
</p>
<p>
Meyer, D. L., and R. A. Davis. 2009. A sea without fish: life in the
Ordovician sea of the Cincinnati region. Indiana University Press, Bloomington
and Indianapolis, Indiana.
</p>
<p></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-71215371427125574082023-07-23T15:31:00.000-05:002023-07-23T15:31:06.105-05:00Your Friends The Titanosaurs: Igai semkhu<p>
This happens to be the 400th post on Equatorial Minnesota, and it's on a
fitting subject, as about 15% of the posts have been on titanosaurs. In fact,
this particular titanosaur has been mentioned before, as a
<a href="https://equatorialminnesota.blogspot.com/2021/05/your-friends-titanosaurs-361-coming-attractions-except-europe-south-america.html" rel="nofollow">potential coming attraction</a>. What was referred to as MB.R.Vb-621–640 in that post now has a name:
<i>Igai semkhu</i>. Let's have a look at what this new genus and species can
tell us.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFGeQp3Ada2kBnqZOlyJxzmrzvNQpQjDpgg7pNgFXeU8VtTqewy6ISoWbREK7UowNShJxqCWni2oB_KTs53gOyYaQivRJh4-A2k9B3gLeJJAMqSeQ5e8zp4C3yhg810_IrZ6HuTiD9NugZ6o6BJJSOIz92B5_C86JjOBg6eCbasCWwlun0s-VvimyGexW9/s1500/igai_semkhu.jpeg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="997" data-original-width="1500" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFGeQp3Ada2kBnqZOlyJxzmrzvNQpQjDpgg7pNgFXeU8VtTqewy6ISoWbREK7UowNShJxqCWni2oB_KTs53gOyYaQivRJh4-A2k9B3gLeJJAMqSeQ5e8zp4C3yhg810_IrZ6HuTiD9NugZ6o6BJJSOIz92B5_C86JjOBg6eCbasCWwlun0s-VvimyGexW9/w400-h266/igai_semkhu.jpeg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Figure 1 from Gorscak et al. (2023), including quarry map (with lost
material), reconstruction, and geographic insets (<a href="https://creativecommons.org/licenses/by-nc-nd/4.0/" rel="nofollow">CC BY-NC-ND-4.0</a>).<br />
</td>
</tr>
</tbody>
</table>
<p><span></span></p><a name='more'></a><p></p>
<p>
<u>Genus and Species</u>: <i>Igai semkhu</i>. This name is unusual in dinosaur
paleontology in being based entirely on ancient Egyptian words and concepts.
"Igai" is the name of a deity, a "lord of the oasis" worshiped around the
Dakhla and Kharga oases, while "semkhu" is a form of the ancient Egyptian verb
meaning "to forget", referring to the post-discovery history of the specimen (Gorscak et al. 2023)
(shades of <i>Thescelosaurus neglectus</i>). The authors
rendered their combination as "the forgotten lord of the oasis".<br />
</p>
<p>
<u>Citation</u>: Gorscak, E., M. C. Lamanna, D. Schwarz, V. Díez Díaz, B. S.
Salem, H. M. Sallam, and M. F. Wiechmann. 2023.
<a href="https://www.tandfonline.com/doi/full/10.1080/02724634.2023.2199810" rel="nofollow">A new titanosaurian (Dinosauria: Sauropoda) from the Upper Cretaceous
(Campanian) Quseir Formation of the Kharga Oasis, Egypt</a>. Journal of Vertebrate Paleontology. e2199810. doi:<a href="https://doi.org/10.1080/02724634.2023.2199810">10.1080/02724634.2023.2199810</a>.
</p>
<p>
<u>Geography and Stratigraphy</u>: <i>I. semkhu</i> comes from south of the
Kharga Oasis, a few km south of Baris in south-central Egypt.
Stratigraphically it hails from the
<a href="https://equatorialminnesota.blogspot.com/p/geologic-time.html" rel="nofollow">Campanian</a>-age Quseir Formation, as does another titanosaur,
<i><a href="https://equatorialminnesota.blogspot.com/2019/10/your-friends-titanosaurs-17-malawisaurus-mansourasaurus-maxakalisaurus.html" rel="nofollow">Mansourasaurus shahinae</a></i>
(albeit from the Dakhla Oasis) (Gorscak et al. 2023). The Quseir is becoming
like the formations in South America; Gorscak et al. reference another
titanosaur specimen from the Kharga Oasis area (this is the one in Salem et
al. 2020), due to be described.<br />
</p>
<p>
<u>Holotype</u>: Vb-621–640 ("vertebrate fossil collection of the
Sonderforschungsbereiches 69 of the Technische Unversität Berlin, Germany",
but held at the Museum für Naturkunde in Berlin). This includes "five
fragmentary
<a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow">dorsal vertebrae</a>, partial left coracoid, partial left ulna, three left metacarpals (I, IV,
and V), the
<a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow">proximal</a>
part of the left pubis, both tibiae (a partial right and the complete and
well-documented but currently missing left, Vb-634), the left fibula, and
three metatarsals (left I, left and right II)" (Gorscak et al. 2023). The
specimen was found associated over a small area.
</p>
<p>
As mentioned in the "Coming Attractions" post, <i>I. semkhu</i> goes back to a
1977 discovery. The holotype was collected in November 1977 by K. Werner
Barthel and Ronald Böttcher of the Technische Unversität Berlin. They had
originally found more of the skeleton; quarry maps indicate more than
30 pieces that were never elucidated and have likely disintegrated. Apparently
not enough or the wrong kind of consolidants were used during collection, although to
be fair, there may not have been a correct conslidant for some of the
material; Gorscak et al. report that "the ends of several limb bones are
preserved essentially as loosely compacted sediment", and you can probably
guess how that would be a problem. In later years, preparation,
transportation (including transfers involving three institutions), and
inadequate storage all took a toll on the material, with the left tibia simply
vanishing at some point between 1999 and 2008. The material that remains
represents the second-best late Late Cretaceous dinosaur specimen from
Africa, after the <i>Mansourasaurus</i> type. This is more of a reflection on
the current rarity of Campanian–Maastrichtian dinosaur fossils from Africa than the
unalloyed greatness of the specimen, as the <i>I. semkhu</i> holotype
underwent some enthusiastic deformation that flattened and sheared bones
(Gorscak et al. 2023).
</p>
<p>
A few references to the specimen escaped over the years (Brinkmann and
Buffetaut 1990; Wieschmann 1999a, 1999b), but formal description had to first
wait for its third institutional change (to the Museum für Naturkunde in 2008)
and finally the initiation of a collaborative effort in the late 2010s. This
produced the abstracts I cited in the other post (Díez Díaz et al. 2017;
Lamanna et al. 2017; Gorscak et al. 2020), and finally the present
publication.
</p>
<p>
Anatomically, <i>I. semkhu</i> definitely falls within the "gracile" camp of
titanosaurs. This is convenient for distinguishing it from robust
<i>M. shahinae</i>, because otherwise they have very little overlap. The
<i>M. shahinae</i> holotype is biased to the front part of the body, while
the <i>I. semkhu</i> holotype is mostly the midsection, with
only the coracoid and first metatarsal in common. (The disassociated ulna
potentially belonging to <i>M. shahinae</i> is also robust, which is a
circumstantial point in favor of it belonging to that species.) The type
individual of <i>I. semkhu</i> appears to have been at least close to maturity
based on the neural arches being fused to the vertebrae, although it is
possible that the coracoid and scapula weren't fused. The ulna is rather
shorter than the tibia (658 mm versus 810 mm [25.9 in versus 31.9 in]),
indicating it was not among the longer-armed titanosaurs. Overall body length
of the type individual is estimated in the 10–15 meter (33–49 feet) range,
moderately sized for a titanosaur and slightly longer than the type individual
of <i>M. shahinae</i> (Gorscak et al. 2023).
</p>
As one of the handful of described African titanosaurs, <i>I. semkhu</i> is of
interest as a data point for the biogeography and evolution of the group. The
phylogenetic analyses of Gorscak et al. (2023) indicate it is most closely
related to several southwest European titanosaurs of similar vintage (<i><a href="https://equatorialminnesota.blogspot.com/2018/06/your-friends-titanosaurs-1-adamantisaurus-aegyptosaurus-ampelosaurus.html" rel="nofollow">Ampelosaurus</a></i>,
<i><a href="https://equatorialminnesota.blogspot.com/2019/08/your-friends-titanosaurs-15-lirainosaurus-lohuecotitan-loricosaurus.html" rel="nofollow">Lirainosaurus</a></i>, and
<i><a href="https://equatorialminnesota.blogspot.com/2019/08/your-friends-titanosaurs-15-lirainosaurus-lohuecotitan-loricosaurus.html" rel="nofollow">Lohuecotitan</a></i>), and more distantly to <i>Mansourasaurus</i>,
<a href="https://equatorialminnesota.blogspot.com/2020/03/your-friends-titanosaurs-22-paludititan-panamericansaurus-paralititan.html" rel="nofollow"><i>Paludititan</i></a>, and
<i><a href="https://equatorialminnesota.blogspot.com/2020/02/your-friends-titanosaurs-21-nullotitan-opisthocoelicaudia-overosaurus.html" rel="nofollow">Opisthocoelicaudia</a></i>
+
<i><a href="https://equatorialminnesota.blogspot.com/2019/12/your-friends-titanosaurs-19-muyelensaurus-narambuenatitan-nemegtosaurus.html" rel="nofollow">Nemegtosaurus</a></i>
(exact configuration varies). This implies a distinct North African/European clade with deeper connections to central Asia.
<p>References</p>
<p>
Brinkmann, W., and E. Buffetaut. 1990. Ein Dinosaurier-Teilskelett (Sauropoda)
aus der Ober-Kreide von Ägypten. Nachrichten-Deutsche Geologische Gesellschaft
43:119–120.
</p>
<p>
Díez Díaz, V., E. Gorscak, M. C. Lamanna, D. Schwarz, and I. El-Dawoudi. 2017.
The metatarsus of a Late Cretaceous titanosaur (Dinosauria: Sauropoda) from
the Kharga Oasis of Egypt. Zitteliana 91:31–32.
</p>
<p>
Gorscak, E., M. C. Lamanna, V. Díez Díaz, D. Schwarz, B. S. Salem, G. Abu
El-Kheir, and H. Sallam. 2020. A titanosaurian sauropod from the Campanian
Quseir Formation of the Kharga Oasis, Egypt, supports Afro-Eurasian dinosaur
faunal connectivity during the Late Cretaceous. Journal of Vertebrate
Paleontology, Program and Abstracts, 2020:no page number because in the future
we just know where things are.
</p>
<p>
Gorscak, E., M. C. Lamanna, D. Schwarz, V. Díez Díaz, B. S. Salem, H. M.
Sallam, and M. F. Wiechmann. 2023.
<a href="https://www.tandfonline.com/doi/full/10.1080/02724634.2023.2199810" rel="nofollow">A new titanosaurian (Dinosauria: Sauropoda) from the Upper Cretaceous
(Campanian) Quseir Formation of the Kharga Oasis, Egypt</a>. Journal of Vertebrate Paleontology. e2199810. doi:<a href="https://doi.org/10.1080/02724634.2023.2199810">10.1080/02724634.2023.2199810</a>.
</p>
<p>
Lamanna, M. C., E. Gorscak, V. Díez Díaz, D. Schwarz, and I. El-Dawoudi. 2017.
Reassessment of a partial titanosaurian sauropod dinosaur skeleton from the
Upper Cretaceous (Campanian) Quseir Formation of the Kharga Oasis, Egypt.
Zitteliana 91:50–51.
</p>
<p>
Salem, B. S., G. Abu El-Kheir, M. C. Lamanna, E. Gorscak, S. El-Sayed, and H.
Sallam. 2020. A new titanosaurian sauropod dinosaur partial skeleton from the
Late Cretaceous (Campanian) of the Kharga Oasis, Western Desert of Egypt.
Journal of Vertebrate Paleontology, Program and Abstracts, 2020:no page number
because in the future we just know where things are.<br />
</p>
<p>
Wiechmann, M. F. 1999a. Ein Titanosaurier-Teilskelett aus dem Campan von
Ägypten/Western Desert. Jahrestagung der Paläontologischen Gesellschaft,
Zürich 69:81–82.
</p>
<p>
Wiechmann, M. F. 1999b. Ein Titanosaurier-Teilskelett aus dem Campan von
Ägypten – Western Desert. Diploma thesis. Institut für Paläontologie, Freien
Universität Berlin, Germany.</p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-57877592891604916692023-07-04T11:55:00.000-05:002023-07-04T11:55:31.616-05:00Fossil Lagomorphs of the National Park Service<p>It's time for the annual focus on the paleontology of a particular group in National Park Service lands. This year we turn from the <a href="https://equatorialminnesota.blogspot.com/2022/07/fossil-felids-of-national-park-service.html" rel="nofollow">felines</a> to one of their prey items, the <a href="https://en.wikipedia.org/wiki/Lagomorpha" rel="nofollow">lagomorphs</a> (rabbits, hares, and pikas). So, why bunnies and pikas? To be honest, most of us have probably never
given more than a moment's thought to the fossil record of lagomorphs, and
that moment probably involved one of three thoughts: a nodding recognition
that fossil rabbits et al. must exist; goofy speculation ("prehistoric saber-toothed
rabbits"); or providing some ancient carnivore an appropriate lunch for a
drawing or story. Well, you know me: I love topics nobody else is talking
about. (I get in fewer arguments that way.) Also, I come from a household that
appreciates small mammals for what they are. In return, they seem to feel
comfortable hanging around. (A
<i><a href="https://en.wikipedia.org/wiki/American_red_squirrel" rel="nofollow">Tamiasciurus hudsonicus</a></i>
deciding your yard is part of its territory provides entertainment value all
winter; the little psychos will take on anything.) For the past couple of
months a young rabbit has been a frequent visitor, so this is my tip of the
cap.<span></span></p><a name='more'></a><p></p>
<p>As noted Lagomorpha includes the rabbits, hares, and pikas. Rabbits and hares are in
the same family (Leporidae) and are generally similar except hares reach
larger sizes and have longer ears. (In the U.S., most hares are known as
jackrabbits, but they're all part of genus
<a href="https://en.wikipedia.org/wiki/Hare" rel="nofollow"><i>Lepus</i></a>.) Pikas belong to the family Ochotonidae and look kind of like small rabbits with short round ears. In North
America they prefer to live in scree accumulations in cool high-elevation
areas (showing admirable preferences in climate and real-estate) and make
adorable squeaking noises. Lagomorphs as a whole show up around the late
Paleocene but don't arrive in North America until the Eocene, with leporids
present in strata such as the upper Eocene Chadron Formation of the White
River Badlands. Although often collectively called "rabbits" as shorthand, it should be
noted that the early leporids were less "hop" and more "run". Pikas are today
something of an afterthought in North America, being confined to the genus
<i><a href="https://en.wikipedia.org/wiki/Pika" rel="nofollow">Ochotona</a></i>, but were more diverse in the past. They were also not as geographically
restricted; as recently as the Pleistocene pikas were present in the
Appalachians, as shown by fissure and cave records (Mead and Grady 1996).
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
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<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmHz9MVuKZ1o6BT8PUb4_XRbDNqoCSCO0ewMG1k-rl64F4RAoe0EJAbMIykoB9hPKwFx32QlWHRjMV4lZYcv4f4JzHNmN62w9iAP3S9oUzp5gETdCdn92RqhtahZxSWPdVbT0ObfxNZc472Iv7e1nrYB31uKKGGR_4L4egaSYjwMTCML8ZHGPD5Gyt2Bn5/s2754/lagomorpha_through_time.png" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2754" data-original-width="1927" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmHz9MVuKZ1o6BT8PUb4_XRbDNqoCSCO0ewMG1k-rl64F4RAoe0EJAbMIykoB9hPKwFx32QlWHRjMV4lZYcv4f4JzHNmN62w9iAP3S9oUzp5gETdCdn92RqhtahZxSWPdVbT0ObfxNZc472Iv7e1nrYB31uKKGGR_4L4egaSYjwMTCML8ZHGPD5Gyt2Bn5/w280-h400/lagomorpha_through_time.png" width="280" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
The shape of Lagomorpha through time (the stem forms are all from Asia).
<a href="https://journals.plos.org/plosone/article/figure?id=10.1371/journal.pone.0059668.g001" rel="nofollow">Figure 1</a>
from
<a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059668" rel="nofollow">Ge et al. (2013)</a>
(<a href="https://creativecommons.org/licenses/by/2.5/" rel="nofollow">CC BY 2.5</a>).<br />
</td>
</tr>
</tbody>
</table><br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi68TLy3cUOSS3hLBMHaS-9re8vtgKeh9LK9lFwMZgiGe75KQusuFk2-V43V207oEG7nBa1Sai3irUfBUu67eKSxgycG5ErVLwdoiQT9HybCsKPzy-DETdGd82jjAN3jdxLUUQMI1fjqgp9l_HWvzuDhAx0jvsUkjJ-MMv5bf7ep9YI2_98g9M0XZ1gxQhQ/s2185/lagomorphs.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1571" data-original-width="2185" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi68TLy3cUOSS3hLBMHaS-9re8vtgKeh9LK9lFwMZgiGe75KQusuFk2-V43V207oEG7nBa1Sai3irUfBUu67eKSxgycG5ErVLwdoiQT9HybCsKPzy-DETdGd82jjAN3jdxLUUQMI1fjqgp9l_HWvzuDhAx0jvsUkjJ-MMv5bf7ep9YI2_98g9M0XZ1gxQhQ/w400-h288/lagomorphs.jpg" width="400" /></a>
</td>
</tr>
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<td class="tr-caption" style="text-align: center;">
Map time! 1. Nez Perce National Historical Park; 2. John Day Fossil Beds
National Monument; 3. Oregon Caves NM; 4. Hagerman Fossil Beds NM; 5.
Craters of the Moon NM and Preserve; 6. Yellowstone National Park; 7.
Grand Teton NP; 8. Timpanogos Cave NM; 9. Great Basin NP; 10. Glen
Canyon National Recreation Area; 11. Grand Canyon NP; 12. Tule Springs
Fossil Beds NM; 13. Sequoia and Kings Canyon NPs; 14. Santa Monica
Mountains NRA; 15. Mojave National Preserve; 16. Joshua Tree NP; 17.
Organ Pipe Cactus NP; 18. Bering Land Bridge NPres; 19. Jewel Cave NP;
20. Wind Cave NP; 21. Badlands NP; 22. Agate Fossil Beds NM; 23.
Niobrara National Scenic River; 24. Florissant Fossil Beds NM; 25. Chaco
Culture National Historical Park; 26. Carlsbad Caverns NP; 27. Guadalupe
Mountains NP; 28. Big Bend NP; 29. Amistad NRA; 30. Mississippi National
River and Recreation Area; 31. Potomac Heritage National Scenic Trail;
32. Valley Forge NHP.<br />
</td>
</tr>
</tbody>
</table>
<p>
The map is 32 parks deep; fossil lagomorphs may well be more abundant at the parks,
just not as frequently recognized as other things. Most of the parks have only
one lagomorphic unit. The exceptions are Badlands NP (Chadron and Brule
Formations), Big Bend NP (Delaho Formation, Banta Shut-In Formation, and
unnamed ?Pliocene alluvium), John Day Fossil Beds NM (John Day, Mascall, and
Rattlesnake Formations); Joshua Tree NP (informal Pinto Formation and unnamed
younger deposits), Niobrara NSR (Valentine Formation and Quaternary deposits),
and Santa Monica Mountains NRA (early Hemingfordian pikas in the upper Sespe
Formation and middle Hemingfordian rabbits in the Topanga Formation). Only 10
have pre-Quaternary lagomorphs, which makes for a fairly compact table and a
fairly good spread:
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVRlsa36M1KKRP7p2bCFkUVmhfedRH7I5gnp9afeCKAgLkBYcGOHBDGSyDRTS2sZtZ_QKcPFxVsc0M6X_hROe2dleQt5XcZuu9-Cc35IX2ONFbsWX5lMlqerS_xn2PqegEpNLu9PDuf_qoVFaJU1SLNNj1ZVpjMWABjJ7ibP6Sy4KoDUNObCq3Qb6b5uOq/s977/lagomorphs_time.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="266" data-original-width="977" height="109" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVRlsa36M1KKRP7p2bCFkUVmhfedRH7I5gnp9afeCKAgLkBYcGOHBDGSyDRTS2sZtZ_QKcPFxVsc0M6X_hROe2dleQt5XcZuu9-Cc35IX2ONFbsWX5lMlqerS_xn2PqegEpNLu9PDuf_qoVFaJU1SLNNj1ZVpjMWABjJ7ibP6Sy4KoDUNObCq3Qb6b5uOq/w400-h109/lagomorphs_time.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Expand to see formation names. I cheated a bit with the John Day
Formation, as I don't have information on hand that would make the
spread more concise.<br />
</td>
</tr>
</tbody>
</table>
<p>
Twenty-three have Quaternary lagomorphs, of which the great majority (17) can
be described as cave or alcove records. This is not to imply that the
Pleistocene was populated by cave rabbits (scree-dwelling pikas are another story). Rather, many cave and alcove
records are predator dens, or fissures that accumulated a little bit of
everything, or packrat middens featuring whatever kind of decor a packrat
fancied at the moment.</p>
<p>
Nine of the 32 have pikas (Grand Teton NP, Great Basin NP, Mojave NPres,
Potomac Heritage NST, Niobrara NSR, Santa Monica NRA, Valley Forge NHP, Wind
Cave NP, and Yellowstone NP); Mojave is the only one with fossils of
pikas only. The pika record is not quite as Quaternary-focused as
the rabbits. Grand Teton, Mojave, Niobrara, and Santa Monica have Miocene
records, and the two Eastern records (Potomac Heritage and Valley Forge) are
not plain old Rancholabrean, corresponding to the early Middle Pleistocene
<a href="https://equatorialminnesota.blogspot.com/2018/11/cumberland-bone-cave.html" rel="nofollow">Cumberland Bone Cave</a>
and
<a href="https://equatorialminnesota.blogspot.com/2020/08/port-kennedy-bone-cave.html" rel="nofollow">Port Kennedy Bone Cave</a>, respectively.
</p>
<p>
Six fossil lagomorphs are known to have been named from areas now in NPS
units, with a seventh possible. They are:<br />
</p>
<p>Pikas:</p>
<ul style="text-align: left;">
<li><i>Oreolagus colteri</i> Barnosky (1986) from Grand Teton NP<br /></li>
<li>
<i>Praotherium palatinum</i> Cope (1871) from Valley Forge NHP (now considered
dubious)
</li>
</ul>
<p>Leporids:</p>
<ul style="text-align: left;">
<li><i>Alilepus vagus</i> Gazin (1934) from Hagerman Fossil Beds NM<br /></li>
<li>
<i>Archaeolagus buangulus</i> Dawson (in Stevens et al. 1969) from Big Bend NP
</li>
<li><i>Hypolagus gidleyi</i> White (1987) from Hagerman</li>
<li>
<i>Hypolagus limnetus</i> Gazin (1934) from Hagerman (now considered a
synonym of <i>Hypolagus edensis</i>)
</li>
<li><i>Palaeolagus haydeni</i> Leidy (1856) possibly from Badlands NP<br /></li>
</ul>
<p>
Unlike rodents, we aren't swarming with different genera and species. While
rabbits of course are quite accomplished at making more of their particular species, they don't seem to have
quite the evolutionary flexibility of rodents. A couple of park sites have
several taxa. The Norden Bridge quarry in Niobrara NSR boasts two pikas (<i>Hesperolagomys fluviatilis</i>
and <i>Russellagus vonhofi</i>) and two rabbits (<i>Hypolagus parviplicatus</i>
and <i>H. </i>cf. <i>H. fontinalis</i>) (Voorhies 1990). (I always enjoy a chance to cite the Norden Bridge site; it's one of the most diverse terrestrial vertebrate sites you could hope to find.) Cave sites of Great Basin NP dating to the late Quaternary are even more diverse, featuring the pika <i>Ochotona</i> (no longer present in the Snake Range), two extinct pygmy rabbits (<i>Aztlanolagus agilis</i> and <i>Brachylagus coloradoensis</i>) plus the extant <i>B. idahoensis</i>, jackrabbits, and desert cottontails (Bell et al. 2016).<br /></p>
<p>References</p>
<p>
Barnosky, A. D. 1986. Arikareean, Hemingfordian, and Barstovian mammals from
the Miocene Colter Formation, Jackson Hole, Teton County, Wyoming. Bulletin of
Carnegie Museum of Natural History 26:1–69.<br /></p><p>Bell, G. L., Jr., J. S. Tweet, and V. L. Santucci. 2016. Great Basin National Park: Paleontological resource inventory. Natural Resource Report NPS/GRBA/NRR—2016/1285. National Park Service, Fort Collins, Colorado.</p>
<p>
Cope, E. D. 1871. Preliminary report on the vertebrata discovered in the Port
Kennedy Bone Cave. Proceedings of the American Philosophical Society
12:73–102.
</p>
<p>
Gazin, C. L. 1934. Fossil hares from the late Pliocene of southern Idaho.
Proceedings of the U.S. National Museum 83:111–121.
</p>
<p>
Ge, D., Z. Wen, L. Xia, Z. Zhang, M. Erbajeva, C. Huang, and Q. Yang. 2013.
<a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059668" rel="nofollow">Evolutionary history of lagomorphs in response to global environmental
change</a>. PLoS ONE 8(4): e59668. doi:<a href="https://doi.org/10.1371/journal.pone.0059668">10.1371/journal.pone.0059668</a>. <br />
</p>
<p>
Leidy, J. 1856. Notices of remains of extinct Mammalia, discovered by Dr. F.
V. Hayden in Nebraska Territory. Proceedings of the Academy of Natural
Sciences of Philadelphia 8:88–90.
</p>
<p>
Mead, J. I., and F. Grady. 1996. <i>Ochotona </i>(Lagomorpha) from late
Quaternary cave deposits in eastern North America. Quaternary Research
45(1):93–101.
</p>
<p>
Stevens, M. S., J. B. Stevens, and M. R. Dawson. 1969. New early Miocene
formation and vertebrate local fauna, Big Bend National Park, Brewster County,
Texas. The Pearce-Sellards Series, Texas Memorial Museum 15.</p><p>Voorhies, M. R. 1990. Vertebrate paleontology of the proposed Norden Reservoir Area, Brown, Cherry, and Keya Paha counties, Nebraska. Division of Archeological Research, University of Nebraska, Lincoln, Nebraska. Technical Report 82-09.</p>
<p>
White, J. A. 1987. The Archaeolaginae (Mammalia, Lagomorpha) of North America,
excluding <i>Archaeolagus </i>and <i>Panolax</i>. Journal of Vertebrate
Paleontology 7:425–450.
</p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-10785752471674266122023-06-27T21:13:00.004-05:002023-06-27T21:14:30.358-05:00Vectipelta barretti<p>Last week we had a look at almost-hadrosaur <a href="https://equatorialminnesota.blogspot.com/2023/06/gonkoken-nanoi.html" rel="nofollow"><i>Gonkoken nanoi</i></a>. This week we're hopping over to another branch of Ornithischia for the ankylosaur <i>Vectipelta barretti</i>. I'm always up for ankylosaur news, and took particular interest in this case because I've long had a deep and irrational fondness for <i>Polacanthus</i>, going back to the 1980s.</p><span><a name='more'></a></span><p></p><p><u>Genus and Species</u>: <i>Vectipelta barretti</i>. The genus name refers to the Isle of Wight under its Roman name of "Vectis" plus the Latin "pelta", meaning "shield" (Pond et al. 2023), a word that crops up fairly regularly in ankylosaur names. The species name honors paleontologist Paul Barrett (Pond et al. 2023), so together we get something like "Paul Barrett's Isle of Wight shield".</p><p><u>Citation</u>: Pond, S., S.-J. Strachan, T. J. Raven, M. I. Simpson, K. Morgan, and S. C. R. Maidment. 2023. <a href="https://www.tandfonline.com/doi/full/10.1080/14772019.2023.2210577" rel="nofollow"><i>Vectipelta barretti</i>, a new ankylosaurian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, UK</a>. Journal of Systematic Palaeontology 21(1):12210577. doi:<a href="https://doi.org/10.1080/14772019.2023.2210577" rel="nofollow">10.1080/14772019.2023.2210577</a>.<br /></p><p><u>Geography and Stratigraphy</u>: The holotype and only known individual came from a fallen block found adjacent to Chilton Chine on the southwest coast of the Isle of Wight, England, United Kingdom. Stratigraphically, the block pertained to Plant Debris bed L5, near the base of the Wessex Formation (Pond et al. 2023). There is a potential issue with the dating, which the authors describe as early Barremian; in recent years the base of the Barremian had been put in the vicinity of 130 million years ago, but <a href="https://stratigraphy.org/ICSchart/ChangeLog2012-2023.txt" rel="nofollow">earlier this year</a> the ICS put it at 125.77 Ma. (Meanwhile I'm sitting here with <a href="https://equatorialminnesota.blogspot.com/p/geologic-time.html" rel="nofollow">a chart</a> based on the 2020 time scale volume, the dates from which are seemingly being adopted piecemeal.) This could mean that the authors' early Barremian should really be middle Hauterivian, but it's difficult to be sure because the Wealden currently doesn't have absolute dates, only relative.</p><p><u>Holotype</u>: <i>V. barretti</i> is based on a partial skeleton traveling under two IWCMS (Dinosaur Isle Museum, Sandown, Isle of Wight) numbers due to acquisition at different times. IWCMS 1996.153 includes <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow">cervical vertebrae</a> and six dorsals. IWCMS 2021.75 includes more dorsals, sacrals, caudals, some rib fragments, a partial scapula, the majority of both ilia plus sacral shield, parts of the other pelvic bones (including most of the left ischium), fragments of a humerus, ulna?, fibula?, and right metatarsal II?, and various osteoderms (Pond et al. 2023).<br /></p><p><i>V. barretti</i> is part of the grand tradition of English Early Cretaceous ankylosaurs, going back to before there were dinosaurs with <i>Hylaeosaurus armatus</i>. This is not the time or place to go into that rich history, except to note that there has been a lot of confusion, uncertainty, and misplaced certainty over the years. (See also the meandering adventures of <i>Iguanodon</i>.) The Early Cretaceous-age rocks of southern England, which we can simply call the Wealden since this is informal and we're all friends, cover some 15 million years. The early end is held down by the historically important obscurity <i>Hylaeosaurus</i> in the Grinstead Clay, while later on <i>Polacanthus foxii</i> shows up in the upper Wessex Formation. In between and above there are plenty of other ankylosaur fossils, from isolated bones and osteoderms up to partial skeletons. In news that should surprise nobody, assigning these remains to a genus or species is tough. The type of <i>Hylaeosaurus armatus</i> consists primarily of the neck and shoulders, whereas <i>Polacanthus foxii</i>'s type is the back end of the animal. There's very little in common (see Figure 3 in Raven et al. 2020),<i> </i>although that hasn't stopped enthusiastic synonymizers during times when the generic pendulum has swung toward lumping. (The "deep time" aspect also was not as greatly appreciated in days past.) <i>Polacanthus</i> shed <i>Hylaeosaurus</i> during the 1990s and in its exuberance at liberation accumulated a number of other specimens, which in hindsight was getting ahead of itself.<br /></p><p>Among the specimens that fell into this polacanthetical morass is the topic of today's post, which has its own mini-odyssey. The 1996.153 material was collected from the beach in November 1993 and donated to the Dinosaur Isle Museum. The 2021.75 material was collected the following spring and found its way to the same repository in 2021. Other specimens found in the same area may belong to the type individual, including a braincase (CAMSM X.26242, Sedgwick Museum of Cambridge University) that was described as cf. <i>Polacanthus</i> by Norman and Faiers (1996), and a partial femur and ilium chunk now at the Natural History Museum (NHMUK PV R16484 and R16485) (Pond et al. 2023). The type individual was recognized as something distinct in recent years, teasing as the "Spearpoint ankylosaur" in Raven et al. (2023).<br /></p><p>Stratigraphically <i>V. barretti</i> fits conveniently between <i>Hylaeosaurus</i> and <i>Polacanthus</i>. Anatomically, it conveniently overlaps both holotypes. There is less to check with <i>Hylaeosaurus</i>, but <i>V. barretti</i> does differ in features such as the lack of a keel on the <a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow">ventral</a> surfaces of the cervical and dorsal vertebrae. <i>V. barretti</i> differs from <i>Polacanthus</i> in features such as the structure and (lack of) ornamentation of the sacral shield, the presence of recurved spines with narrow bases, and the absence of "splates" (Pond et al. 2023). In the big picture, a third diagnostic ankylosaur from the lengthy Wealden (and two in the Wessex) hammers home that one cannot blindly use stratigraphy as a proxy for taxonomy (makes me sound smart, doesn't it? Basically you can't safely assign specimens to a species just because of the rock layer).<br /></p><p>One of the most visible aspects of an ankylosaur is its bony armor, and <i>V. barretti</i>'s type specimen comes with a strong selection. As usual, most can only be placed generally on the body. There is a sacral shield, but individual scutes are not clearly defined. Instead, the surface is "gently undulating, with circular, depressed areas that form part of the very low-relief ornamentation" (Pond et al. 2023). This may constitute a new type of sacral shield. The authors describe the isolated osteoderms in terms of five broad groups. "Recurved spines" have expanded bases and compressed spines curved posteriorly (direction assumed), perhaps from the pectoral region. "Flattened, blade-like spines" are even more compressed and are not curved, with acutely concave bases, again potentially from the pectoral region; they are restored along the sides of the animal. "Plates" are broader than the previous two types but still flat, and have skinny bases, with the best example perhaps from the area of the hips. Finally, "small spines with unexpanded bases" and "low keeled scutes" are exactly what they sound like.<br /></p><p></p><p>Pond et al. (2023) ran <i>V. barretti</i> through a phylogenetic analysis and found it to be close to Ankylosauridae, in a little clade with <i>Dongyangopelta</i> and <i>Zhejiangosaurus</i>, somewhat younger and fairly obscure ankylosaurs from China. This is certainly not implausible, but I reserve the right to be cautious; I trust ankylosaur phylogenies slightly more than I trust titanosaur phylogenies, which ain't saying much. Non-ankylosaurids in particular show a disinclination to keep their dance partners or stay in one place from paper to paper. This is all a long way of apologizing for having a lot of nodosaurs over in <a href="https://docs.google.com/spreadsheets/d/1NzXo_m3z-RlocqbkAL7QNf5q33qmT65uaut9okLOmqs/edit#gid=0" rel="nofollow">The Compact Thescelosaurus</a>.<br /></p><p></p><p>References</p><p>Norman, D. B., and T. Faiers. 1996. On the first partial skull of an ankylosaurian dinosaur from the Lower Cretaceous of the Isle of Wight, southern England. Geological Magazine 133:299–310. <br /></p><p>Pond, S., S.-J. Strachan, T. J. Raven, M. I. Simpson, K. Morgan, and S. C. R. Maidment. 2023. <a href="https://www.tandfonline.com/doi/full/10.1080/14772019.2023.2210577" rel="nofollow"><i>Vectipelta barretti</i>, a new ankylosaurian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, UK</a>. Journal of Systematic Palaeontology 21(1):12210577. doi:<a href="https://doi.org/10.1080/14772019.2023.2210577" rel="nofollow">10.1080/14772019.2023.2210577</a>.</p><p>Raven, T. J., P. M. Barrett, S. B. Pond, and S. C. R. Maidment. 2020. <a href="https://www.tandfonline.com/doi/abs/10.1080/02724634.2020.1826956?journalCode=ujvp20" rel="nofollow">Osteology and taxonomy of British Wealden Supergroup (Berriasian–Aptian) ankylosaurs (Ornithischia, Ankylosauria)</a>. Journal of Vertebrate Paleontology 40(4): article e1826956. doi:<a href="https://doi.org/10.1080/02724634.2020.1826956">10.1080/02724634.2020.1826956</a>.<br /></p><p>Raven, T. J., P. M. Barrett, C. B. Joyce, and S. C. R. Maidment. 2023. <a href="https://www.tandfonline.com/doi/full/10.1080/14772019.2023.2205433" rel="nofollow">The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora)</a>. Journal of Systematic Palaeontology 21(1): article 2205433. doi:<a href="https://doi.org/10.1080/14772019.2023.2205433">10.1080/14772019.2023.2205433</a>.<br /></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-70193247393815863622023-06-19T15:29:00.002-05:002023-06-19T15:29:40.022-05:00Gonkoken nanoi<p>The Great Dinosaur Drought of 2022–2023 persisted from mid-December 2022 to early June 2023, nearly six months with three new dinosaurs and one silesaur, but with five showing up in the past few weeks, it looks like things have gone back to business as usual. Obviously that calls for some recognition, so this week and next week (pending anything else) I'll look at a couple of new arrivals, starting with the not-quite-hadrosaurid <i>Gonkoken nanoi</i> from the south end of Chile.</p><p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUCkj2CNzjBg6p8J92SB6ZTDwPxhjHg0V1Ifuv2b_3AZXYNsQ1Uo0LQ_1jb8_Wk_8jPNQchmhrQJeJymUNWKSdo5YIEqTz17u7QJztvfcT6lmoY8i0V7NKMn1WPIklGXfbFlXajL0WbWW2VKJX981tY4eqdVQidqq3HANT8HaNHgQQloBuSU7mRZtflPcO/s2160/gonkoken_reconstruction_bones.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1981" data-original-width="2160" height="366" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUCkj2CNzjBg6p8J92SB6ZTDwPxhjHg0V1Ifuv2b_3AZXYNsQ1Uo0LQ_1jb8_Wk_8jPNQchmhrQJeJymUNWKSdo5YIEqTz17u7QJztvfcT6lmoY8i0V7NKMn1WPIklGXfbFlXajL0WbWW2VKJX981tY4eqdVQidqq3HANT8HaNHgQQloBuSU7mRZtflPcO/w400-h366/gonkoken_reconstruction_bones.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Figure 2 in Alarcón-Muñoz et al. (2023), showing a reconstruction of <i>Gonkoken nanoi</i> and an assortment of bones (<a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>).<br /></td></tr></tbody></table></p><a name='more'></a><p></p><p><u>Genus and species</u>: <i>Gonkoken nanoi</i>. The genus name is a combination of two <a href="https://en.wikipedia.org/wiki/Tehuelche_people" rel="nofollow">Aónik’enk</a> words, "gon" ("same as" or "similar to") and "koken" ("wild duck" or "swan"), and the species name honors Mario "Nano" Ulloa, "who first found dinosaur bones at Río de las Chinas Valley and provided key logistic help during our expeditions" (Alarcón-Muñoz et al. 2023). Together this comes out to something like "wild-duck-like [animal] of Nano".<br /></p><p><u>Citation</u>: Alarcón-Muñoz, J., A. O. Vargas, H. P. Püschel, S. Soto-Acuña, L. Manríquez, M. Leppe, J. Kaluza, V. Milla, C. S. Gutstein, J. Palma-Liberona, W. Stinnesbeck, E. Frey, J. P. Pino, D. Bajor, E. Núñez, H. Ortiz, D. Rubilar-Rogers, and P. Cruzado-Caballero. 2023. <a href="https://www.science.org/doi/10.1126/sciadv.adg2456" rel="nofollow">Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile</a>. Science Advances 9(24). doi:<a href="https://doi.org/10.1126/sciadv.adg2456">10.1126/sciadv.adg2456</a>. [that's a lot of authors!]<br /></p><p><u>Stratigraphy and geography</u>: <i>G. nanoi</i> come from the upper Dorotea Formation, dated to the early Maastrichtian (between 71.7 ± 1.2 and 70.5 ± 5.0 Ma). This formation came up briefly before as a <a href="https://equatorialminnesota.blogspot.com/2021/05/your-friends-titanosaurs-362-coming-attractions-europe-south-america.html" rel="nofollow">source of unnamed titanosaurs</a>. The fossils of the new species were found at Loma Koken in the Río de las Chinas Valley, Estancia Cerro Guido, Magallanes Region, near the southern tip of Chile (Alarcón-Muñoz et al. 2023).<br /></p><p><u>Holotype</u>: CPAP 3045 (Paleontological Collection of Antarctica and Patagonia, Instituto Antártico Chileno (INACH), Punta Arenas, Chile), a right <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow">ilium</a> (Alarcón-Muñoz et al. 2023). (And now, thanks to an acronym with multiple usages, I have yet another post that will receive mistaken visitors.)</p><p>The solitary holotype is a bit misleading; <i>G. nanoi</i> was found in a bonebed of multiple individuals, with quite a few other bones. These include bones of the skull and lower jaws; cervicals, dorsals, a partial sacrum, and caudals; ribs; scapula and sternal bones; more ilia and parts of the other pelvic bones; and femora, tibiae, a partial fibula, and a metatarsal. The authors reported at least three individuals based on left humeri and right femora, but there's also a fragment of a left humerus mentioned in the supplementary information, and there's also at least one juvenile, so I suspect at least five. This is a minor quibble, though, as the bonebed has not been completely excavated or evaluated. A similar bone-bearing horizon apparently extends another 5 km (3 mi) to the northeast in the valley, part of a floodplain system (Alarcón-Muñoz et al. 2023).<br /></p><p><i>G. nanoi</i>'s species name can also function as a sideways pun, as we are not dealing with a large animal as hadrosaurs go. Alarcón-Muñoz et al. (2023) estimated the body size as 4 m (13 ft) long, and the largest measured femur is 485.1 mm (19.1 in) long. As befits something that is not quite a true hadrosaurid, there are fewer tooth positions and a less elongate skull. Proportionally, the overall impression I have is of something kind of chunky, although we should consider the reconstruction as provisional given how bonebeds work.</p><p><i>G. nanoi</i> is more remarkable in terms of implications than anatomy. If you're reading this post, you've probably got a decent idea of what an almost-hadrosaurid looks like, and <i>G. nanoi</i> is so far not doing anything unusual, although to be fair with the known material there's a chance the nasal has a ridge or there are some exaggerated neural spines or something. Phylogenetically, <i>G. nanoi</i> comes out as the <a href="https://en.wikipedia.org/wiki/Sister_group" rel="nofollow">sister taxon</a> to the sister to the sister of Hadrosauridae, which makes it something of an anachronism in an age when true hadrosaurids had almost achieved a large-ornithopod monopoly (and also acts as an inspiration for the use of "gon" ["similar to"] in the name). In fact, if you want a transitional hadrosaur that's reliably dated as younger, the field is basically <i>Telmatosaurus</i>. <i>G. nanoi</i> is also rather more complete than its nearest compatriots, which should be helpful for further studies in this part of the ornithopod tree. An interesting side result of the phylogenetic analysis is that the other included South American taxa (<i>Bonapartesaurus rionegrinus</i>, <i>Huallasaurus australis</i>, <i>Kelumapasaura machi</i>, and <i>Secernosaurus koerneri</i>) form a clade paired with the gryposaurs, which Alarcón-Muñoz et al. designate Austrokritosauria.<br /></p><p>This leads to the conclusion that there were at least two distinct lineages of hadrosaurs in South America near the end of the Cretaceous, one of hadrosaurids and another of almost-hadrosaurids. This knowledge complicates any assignment of hadrosaur-like pieces-parts found in South America and down to Antarctica; they can't simply be attributed to Hadrosauridae. Alarcón-Muñoz et al. go further into an analysis of dispersal and distribution. Both lineages most likely originated in North America and dispersed south. <i>G. nanoi</i> is the most southerly hadrosaur to be formally named, and all of the bits of comparable or more southerly latitude are not inconsistent with similar almost-hadrosaurids. The authors propose that <i>G. nanoi</i>'s lineage arrived in South America before Austrokritosauria. This would make southern Patagonia a refugium for transitional hadrosaurs in the face of the hadrosaurid advance (<i>G. nanoi</i> being an approximate contemporary of some South American true hadrosaurids). (Now that I think of it, where are the Brazilian hadrosaurids? Is the Brazilian Late Cretaceous so far only represented by settings preferred by titanosaurs?) The authors also comment briefly on the capacity of hadrosaurs for dispersal. While I'm not sure I would go so far as to consider them semiaquatic, I do agree that as large animals with capacious buoyant guts and no obvious anatomical anchors, they were probably well-suited for dispersal by water, much like titanosaurs and elephants.</p><p></p><p>References<br /></p><p>Alarcón-Muñoz, J., A. O. Vargas, H. P. Püschel, S. Soto-Acuña, L.
Manríquez, M. Leppe, J. Kaluza, V. Milla, C. S. Gutstein, J.
Palma-Liberona, W. Stinnesbeck, E. Frey, J. P. Pino, D. Bajor, E. Núñez,
H. Ortiz, D. Rubilar-Rogers, and P. Cruzado-Caballero. 2023. <a href="https://www.science.org/doi/10.1126/sciadv.adg2456" rel="nofollow">Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile</a>. Science Advances 9(24). doi:<a href="https://doi.org/10.1126/sciadv.adg2456">10.1126/sciadv.adg2456</a>.</p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-61240328974574612662023-06-04T13:43:00.004-05:002023-06-04T13:43:59.333-05:00Uŋčí Makhá Park Revisited, Part 2: Further Fossils<p>We're now up to the fourth entry in a
<a href="https://equatorialminnesota.blogspot.com/2022/10/strolling-on-magnolia-member-by-hidden.html" rel="nofollow">completely</a>
<a href="https://equatorialminnesota.blogspot.com/2022/11/quick-guide-to-fossils-at-unci-makha-park.html" rel="nofollow">unexpected</a>
<a href="https://equatorialminnesota.blogspot.com/2023/05/unci-makha-park-revisited-part-1-freeze-thaw.html.html" rel="nofollow">series</a>
on the Platteville–Decorah rocks and fossils of Uŋčí Makhá Park. We've already
seen the common fossils from the site, so for this go-round I'm focusing on
rarities.
</p>
<a name='more'></a>
<p></p>
<p><b>Bryozoans</b></p>
<p>
I had no photos of bryozoans in the previous post, but this time I have
returned with evidence of bryozoans, albeit in the Carimona Member of the
Decorah rather than the more prominent Magnolia Member of the Platteville. One
of the questions I had from the visits in the fall was whether there were more
exposures of fossiliferous Carimona beds. It turns out there are, but are
distributed sporadically (one horizon in particular).
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiteQL31e8cgAJOk4Jia7X86rOknefT-Z1bSqpAxoX4y0hAUZzmYlt08-6agJLx3k2pHVErhnioiJaprS3qeaDCZx78uiDY7ekPr6TqbFi0Le8-5nB0Ys6mSvGWyGzp4IbeGzpD_t9hfKPKTMenkPmbKY5lKx3BYV2MCQ5zwUzqctq2LdzUt6p4uHVF9A/s3650/carimona_bryozoans.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2313" data-original-width="3650" height="254" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiteQL31e8cgAJOk4Jia7X86rOknefT-Z1bSqpAxoX4y0hAUZzmYlt08-6agJLx3k2pHVErhnioiJaprS3qeaDCZx78uiDY7ekPr6TqbFi0Le8-5nB0Ys6mSvGWyGzp4IbeGzpD_t9hfKPKTMenkPmbKY5lKx3BYV2MCQ5zwUzqctq2LdzUt6p4uHVF9A/w400-h254/carimona_bryozoans.jpg" width="400" /></a>
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Persistence is rewarded with twiggy bryozoans.<br />
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<p><b>Brachiopods</b></p>
<p>
Practically all of the brachiopods that can be seen at the park are articulate
forms. In one of the Magnolia landscaping blocks, though, I noticed this
lingulid brachiopod.
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7T5EPlmMs8bYoQpuL0qPEcV-kfStCq1TBSRdUbHCk3S5XcHt1FEIdl_VuVz5X4H1bBxtRoSSqjF2446cogETkJZfMz8KxdaKtkVfuQVrj2Nu5S6JOEHXCNJFzPSpDhfBmvWAi5_Cfk4-kJK43w1IXp6xm6AJOmn8EMVVY_FagqWwDalDKz8azCd4WHw/s1866/lingulid.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1866" data-original-width="1575" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7T5EPlmMs8bYoQpuL0qPEcV-kfStCq1TBSRdUbHCk3S5XcHt1FEIdl_VuVz5X4H1bBxtRoSSqjF2446cogETkJZfMz8KxdaKtkVfuQVrj2Nu5S6JOEHXCNJFzPSpDhfBmvWAi5_Cfk4-kJK43w1IXp6xm6AJOmn8EMVVY_FagqWwDalDKz8azCd4WHw/w338-h400/lingulid.jpg" width="338" /></a>
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The fossil is in the side of a block; a vertical orientation is actually
life position for these brachiopods.<br />
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<p></p>
<p>
Then there's this. I initially interpreted the large shell impression in the
following photo as a bivalve with a deep bulbous shell, but after further
consideration, the symmetric shape of the shell plus the clarity and style of
preservation of the growth lines lead me to interpret it as another lingulid
(perhaps <i>Pachyglossella</i> [aka <i>Lingula</i>] <i>elderi</i> or something
along the same lines). A much smaller true bivalve impression is visible in
the lower right, and a couple of gastropod steinkerns are also present. There
is also an odd bit of corduroy near the center; it's poorly exposed and could
be anything from a slice of warped ribbed brachiopod to a strongly textured
gastropod (see also the third-to-last photo in this post).
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsrTg2gFzipw84lPP0X-ndY61yqVberbR1ILfddMVqehSa6cKc5Px7_9n8v9oVlt8wYBDXzxKMhVtCPE_6TE96BFqCyAgn_iALuNLQfiGE_rfdmHR7yQuc1NYIgRKX_ymV-MB-Y2U9b5xkEhdf0vYlk6NHQMzKM1hZ1vMi8kcXZTrl-LVzJRbAyYcyZQ/s1991/several_mollusks.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1759" data-original-width="1991" height="354" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsrTg2gFzipw84lPP0X-ndY61yqVberbR1ILfddMVqehSa6cKc5Px7_9n8v9oVlt8wYBDXzxKMhVtCPE_6TE96BFqCyAgn_iALuNLQfiGE_rfdmHR7yQuc1NYIgRKX_ymV-MB-Y2U9b5xkEhdf0vYlk6NHQMzKM1hZ1vMi8kcXZTrl-LVzJRbAyYcyZQ/w400-h354/several_mollusks.jpg" width="400" /></a>
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Plus the usual strophomenids.
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<p><b>Bivalves</b></p>
<p>
I don't usually have a lot of bivalve photos. Here's a couple of shells in
side view:
</p>
<p></p>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj31k3sNnqgmIT2uX-oj9WlZ3eaZ-enORguRNp3C44FkNxqQeZmEL1V_NGm_jqd-9OC0Hu4CgkMUkozzfddNSethY3CAY_G5bi11A-mh8ZSKrQU9j04fJjXOnl9yS7ekKVHR8Z4ct4qX5xOxD8Gk22loOxRnewiAJpHblZ1zAjrMl_JJNZYS9VzcilJRA/s1399/bivalve_side_1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="927" data-original-width="1399" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj31k3sNnqgmIT2uX-oj9WlZ3eaZ-enORguRNp3C44FkNxqQeZmEL1V_NGm_jqd-9OC0Hu4CgkMUkozzfddNSethY3CAY_G5bi11A-mh8ZSKrQU9j04fJjXOnl9yS7ekKVHR8Z4ct4qX5xOxD8Gk22loOxRnewiAJpHblZ1zAjrMl_JJNZYS9VzcilJRA/w400-h265/bivalve_side_1.jpg" width="400" /></a>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtpaO_NkHthSYGSHW7Del0HU-O6K46rp48rlTs5sDtHGzsNhyoj-S2bgTzV-GqO9Hj_6fN1wrpg98U4cW_vaa4qkPwPASIsKed83wa--hJbiVX9Y7Jr6-yvqZ1wSSWmMvtNc69-IzgoB6AbnhNofnIPr59ORL9BMd9SWF88hrWMhXQnDqEbuRIzMdYHw/s1971/bivalve_side_2.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1794" data-original-width="1971" height="364" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtpaO_NkHthSYGSHW7Del0HU-O6K46rp48rlTs5sDtHGzsNhyoj-S2bgTzV-GqO9Hj_6fN1wrpg98U4cW_vaa4qkPwPASIsKed83wa--hJbiVX9Y7Jr6-yvqZ1wSSWmMvtNc69-IzgoB6AbnhNofnIPr59ORL9BMd9SWF88hrWMhXQnDqEbuRIzMdYHw/w400-h364/bivalve_side_2.jpg" width="400" /></a>
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Well, technically steinkerns, as usual. They look kind of like soft
hats.<br />
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<p><b>Nautiloids</b></p>
<p>The seasonals picked out a couple of interesting nautiloid fossils:</p>
<p></p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJT962_n9YpF9H6vrQ8__0JHW6DuMCMYZaKgOvgfJ70AjkZV2C74u8h97ciiCXaPVNbWTl4u0HFBrmLV0u1fiJJBIeTIp5Ni1IaHr4OKaHUnnwUqHOLqk-nMGqXMrfABStYxy-QUCbrXpofqDHrP30N0fXGI4o3B1asFMeeZDPdqBw4liqi7fkeXG5KA/s2498/curved_nautiloid_2.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2023" data-original-width="2498" height="324" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJT962_n9YpF9H6vrQ8__0JHW6DuMCMYZaKgOvgfJ70AjkZV2C74u8h97ciiCXaPVNbWTl4u0HFBrmLV0u1fiJJBIeTIp5Ni1IaHr4OKaHUnnwUqHOLqk-nMGqXMrfABStYxy-QUCbrXpofqDHrP30N0fXGI4o3B1asFMeeZDPdqBw4liqi7fkeXG5KA/w400-h324/curved_nautiloid_2.jpg" width="400" /></a>
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This is probably <i>Beloitoceras</i> <i>pandion</i>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicCu1PDkwKavo2wEkimIItqrzn3d40NAUcUHW_S4DKsatsKqx_9AFeOhfEHPDRn4Hw3yuseDP1lCG5z_ZLhXDJmo75QUzGg1zlkH4a5QrXTYpt1N04OrXgQ_kOW64WtlzH_QLTEEmTDWPesdC-NfpZcmuLycsEqbvGTbATPJ2IHx3xyjBZsyHO6Ky08g/s2732/plectoceras.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2383" data-original-width="2732" height="349" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicCu1PDkwKavo2wEkimIItqrzn3d40NAUcUHW_S4DKsatsKqx_9AFeOhfEHPDRn4Hw3yuseDP1lCG5z_ZLhXDJmo75QUzGg1zlkH4a5QrXTYpt1N04OrXgQ_kOW64WtlzH_QLTEEmTDWPesdC-NfpZcmuLycsEqbvGTbATPJ2IHx3xyjBZsyHO6Ky08g/w400-h349/plectoceras.jpg" width="400" /></a>
</td>
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It's hard to tell from the photo, but this is a half-circle void with
fragments of chamber walls. I'm interpreting it as the coiled nautiloid
<i>Plectoceras</i>.<br />
</td>
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<p>Later, I spotted this one in a block:</p>
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<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVCNcf4n7MRTx1M_SahQL7tygjXkeTVifAAxjCRs3Hr51IPUppCr-1f9qbNDTYKq57IdE9bVMahWtmmWKiPgLE8xYVCoOsvzZ2rWEHynOq8dLDYytLxZUO_7qGs3DlWaZv9yousqRm32vdo34YolI-_anF4MiwC1Ig99WgHBineiLDNgA3m5E2A95h8w/s3618/orthocone.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3139" data-original-width="3618" height="348" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVCNcf4n7MRTx1M_SahQL7tygjXkeTVifAAxjCRs3Hr51IPUppCr-1f9qbNDTYKq57IdE9bVMahWtmmWKiPgLE8xYVCoOsvzZ2rWEHynOq8dLDYytLxZUO_7qGs3DlWaZv9yousqRm32vdo34YolI-_anF4MiwC1Ig99WgHBineiLDNgA3m5E2A95h8w/w400-h348/orthocone.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Your typical orthocone mold, surrounded by brachs. There's also a horn
coral (corduroy acorn) sticking out of the side near the lower right
corner.<br />
</td>
</tr>
</tbody>
</table>
<p></p>
<p><b>Gastropods</b><br /></p>
<p>
We saw a number of gastropods last time, so there's no need to go over that
ground again, but here's a parade of snail steinkerns.
</p>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWBb4MOdAwKNDUXA9lNspPyg2wsnX2OJEoXHSYUYvUO0NQ2BUNtGwoI_fYjHcOOjcK7GgqfRP8wWDZXmzJ9kkt430JWKSTndWYeqkwKa6wWSwYzsMMuDxPhqxQqkrkyKxVIi83yCQge_hPueaw_J5ULgfJ0ohW6GknoSyAc0CHLL9tR5s1MUgV7wuXVw/s1794/snail_parade.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1379" data-original-width="1794" height="308" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWBb4MOdAwKNDUXA9lNspPyg2wsnX2OJEoXHSYUYvUO0NQ2BUNtGwoI_fYjHcOOjcK7GgqfRP8wWDZXmzJ9kkt430JWKSTndWYeqkwKa6wWSwYzsMMuDxPhqxQqkrkyKxVIi83yCQge_hPueaw_J5ULgfJ0ohW6GknoSyAc0CHLL9tR5s1MUgV7wuXVw/w400-h308/snail_parade.jpg" width="400" /></a>
</div>
<p></p>
<p><b>Trilobites</b></p>
<p>
One of the nicer fossils we saw is this piece of <i>Isotelus</i> cheek.<br />
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB6m5d8S-eRhptRX97JazUdh5FVp6XZeyd8zKby-SfZ-rsVGTcnJ-Bw1Sl0pYDnKvnM7EiNo7AeAEdU7NBvaG8gpxqoYFJ3QymCTRlwNiQ7KxDw9F_VWXfg2-5GyjoEh9NTBScJDiEg3SpRqBtK9pz8DqT6a8KE0554oi-ay7-0nf-RvbgCFWNswy1Cg/s3103/isotelus.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1757" data-original-width="3103" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB6m5d8S-eRhptRX97JazUdh5FVp6XZeyd8zKby-SfZ-rsVGTcnJ-Bw1Sl0pYDnKvnM7EiNo7AeAEdU7NBvaG8gpxqoYFJ3QymCTRlwNiQ7KxDw9F_VWXfg2-5GyjoEh9NTBScJDiEg3SpRqBtK9pz8DqT6a8KE0554oi-ay7-0nf-RvbgCFWNswy1Cg/w400-h226/isotelus.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Fine structural features are apparent when you zoom in. Note also the
<i>Hesperorthis</i> just below and to the right.<br />
</td>
</tr>
</tbody>
</table>
<p>
The Kentucky Geological Survey has a
<a href="https://www.uky.edu/KGS/fossils/fossil-month-10-2021-Isotelus.php" rel="nofollow">good page</a>
covering this trilobite of unusual size.
</p>
<p></p>
<p><b>Ostracodes</b></p>
<p>
Last time I mentioned that I wasn't sure if I had an ostracode. This time I'm
pretty sure.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidJHtho052C06esfSbcGE293qSn3bCmI7_i83WFeMoW-82pf_laYLa0HSuLnUvHa6dBopawkYsuhAFbhJm9BiHPwt5ZVppgKtkxb-OWm6y3Ofng0h1oCOY4E4Yu1EqTpafHiF0-mWEEFNWhxX5U0Jgsonvia8yOymOQKGCLqdUr4HcyROV9ldNTxpkMA/s1557/eoleperditia.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1203" data-original-width="1557" height="309" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidJHtho052C06esfSbcGE293qSn3bCmI7_i83WFeMoW-82pf_laYLa0HSuLnUvHa6dBopawkYsuhAFbhJm9BiHPwt5ZVppgKtkxb-OWm6y3Ofng0h1oCOY4E4Yu1EqTpafHiF0-mWEEFNWhxX5U0Jgsonvia8yOymOQKGCLqdUr4HcyROV9ldNTxpkMA/w400-h309/eoleperditia.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
<i>Eoleperditia fabulites</i> (again with the wonky color balance).<i><br /></i>
</td>
</tr>
</tbody>
</table>
<p></p>
<p><b>Crinoids</b></p>
<p>
Below is the coolest fossil found by the seasonals: a partial crinoid stem a
few inches long.
</p>
<p></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYjnJc5aIdjfGmc9pSOxg6Ogl0WBQ-8Cb2xddLaR2esm8vFS1ZPR6rrYb9-cs5uvNOIHT6aDh5e8tajM-7B3mscgULJFJXLyFH_xLMJIGKAnCc-rrzYyByWREl0a2aH0nJDBySr6Ac0RncDWO1xn9o66JPUpEsxbYqpPZFm4BqG1j07f6d6K07fFgnPg/s4325/crinoid_stem.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1589" data-original-width="4325" height="148" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYjnJc5aIdjfGmc9pSOxg6Ogl0WBQ-8Cb2xddLaR2esm8vFS1ZPR6rrYb9-cs5uvNOIHT6aDh5e8tajM-7B3mscgULJFJXLyFH_xLMJIGKAnCc-rrzYyByWREl0a2aH0nJDBySr6Ac0RncDWO1xn9o66JPUpEsxbYqpPZFm4BqG1j07f6d6K07fFgnPg/w400-h148/crinoid_stem.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
They always cut out just as they're getting interesting.<br />
</td>
</tr>
</tbody>
</table>
<p></p>
<p><b>Trace Fossils</b></p>
<p>
Either I was paying more attention to burrows this time, or a season of
weathering had brought a few more to the surface, but the burrows were
outstanding and included a variety of forms.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAZ4Gyn-G0Tmlk3J9nn6DKFKwDAQyuAAs4jI5KmB19x83y8nohFnRJ2f8R_Y4_1MEx4BHd9t6CxckLviEfRGEH7lWgsLEQPQ7oI2vf2rdUZ5FXsEi3MnfPp3f6Wmypw76D7rg27dEjNNh9sNhPhzplzNymSaaT7nVT_Gib-8Sb07ONdZkhwKWnHr_JMw/s1523/reverse_zorro.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1523" data-original-width="1086" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAZ4Gyn-G0Tmlk3J9nn6DKFKwDAQyuAAs4jI5KmB19x83y8nohFnRJ2f8R_Y4_1MEx4BHd9t6CxckLviEfRGEH7lWgsLEQPQ7oI2vf2rdUZ5FXsEi3MnfPp3f6Wmypw76D7rg27dEjNNh9sNhPhzplzNymSaaT7nVT_Gib-8Sb07ONdZkhwKWnHr_JMw/w285-h400/reverse_zorro.jpg" width="285" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Nothing of particular scientific import, I just liked this vertical
reverse mark of Zorro.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTJWlSjZbMRnKxHfr2zHIQ4l8b9T2zyGakbUEv7k9npFUbWJcI7hZvQCcE6331MuvTPHxzmhBe0UY_RhTX2FUzy-NYTuATqoGOCyqB44biLFtQWLlxoa7l35_yFWiqptf2A8JtOGq8NIqBUSbGcz6g-ZMYGOxLVN7dIQUTDXG0jgNavD2pSXlMTYz_Zw/s1989/vertical%20burrow.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1989" data-original-width="1624" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTJWlSjZbMRnKxHfr2zHIQ4l8b9T2zyGakbUEv7k9npFUbWJcI7hZvQCcE6331MuvTPHxzmhBe0UY_RhTX2FUzy-NYTuATqoGOCyqB44biLFtQWLlxoa7l35_yFWiqptf2A8JtOGq8NIqBUSbGcz6g-ZMYGOxLVN7dIQUTDXG0jgNavD2pSXlMTYz_Zw/w326-h400/vertical%20burrow.jpg" width="326" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
A winding vertical burrow.<br />
</td>
</tr>
</tbody>
</table>
<p>
There were also lumps of various origins associated with some of the burrows.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwVk-pOfZ10H1J18OhG35ttdqdIB6YcUVGpyIJRzpW986B2Xwab0AchREjA0dj2KYaTzV1ZVfsmmqZwjPCRQm6qccLlA1zNXO2nJ-WWrtngi3kl0nv4p4cBaR3YGksNzKFjfbdhexAAdEvF74ZlNel7_m837VzhJEmod-IZGGJwF3S4saAeLxu0LCEwg/s3806/carimona_lumps.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2276" data-original-width="3806" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwVk-pOfZ10H1J18OhG35ttdqdIB6YcUVGpyIJRzpW986B2Xwab0AchREjA0dj2KYaTzV1ZVfsmmqZwjPCRQm6qccLlA1zNXO2nJ-WWrtngi3kl0nv4p4cBaR3YGksNzKFjfbdhexAAdEvF74ZlNel7_m837VzhJEmod-IZGGJwF3S4saAeLxu0LCEwg/w400-h239/carimona_lumps.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
This is in a Carimona landscaping block. I suspect the lumps are shell
traces and the block is upside down.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFi_qQKwh87cwbR_RVgwmzVHZgjMJCh8ESwIOyz7SOkJr2XOhoo6Frnc6oGqqMvmpDTKU7zjpMjcHQujTQOqfxuLN5l0a868iksbA67abIRysMBzUttl0AeoQ7gLhBRPpCWG2xXOOFaq8y81t1W_-5hD87bR2dwt-g7PlYml3EpOAH3JaJV9GkVjrLvw/s3939/lumpy.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1852" data-original-width="3939" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFi_qQKwh87cwbR_RVgwmzVHZgjMJCh8ESwIOyz7SOkJr2XOhoo6Frnc6oGqqMvmpDTKU7zjpMjcHQujTQOqfxuLN5l0a868iksbA67abIRysMBzUttl0AeoQ7gLhBRPpCWG2xXOOFaq8y81t1W_-5hD87bR2dwt-g7PlYml3EpOAH3JaJV9GkVjrLvw/w400-h188/lumpy.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
This one is in the Magnolia. The large lump on the left is clearly a
brachiopod, but the whole underlying structure is intriguingly
irregular, perhaps representing a collapsed lining.<br />
</td>
</tr>
</tbody>
</table>
<p>
The wrinkled surface of the irregular Magnolia burrow is reminiscent of a
couple of other traces I observed at the site.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipmWnfkT0ZV3PAcoyMwxExCxV5wphC1IC_WwgcK5adSdg2FtkPAE3K3-E2V8tvRqkSeARrPm4tmWmLHViDGFhS8xEd36CyPrDjpJTcxqqCSXCJ7WIV3mOqbVjjhiGdmVnHUzDc_3Ahxr7XV0f-evwx_YWOyERaLI63LGFdjY-89IsxiAdn8_ouAe9miQ/s3087/large_burrow.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2086" data-original-width="3087" height="270" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipmWnfkT0ZV3PAcoyMwxExCxV5wphC1IC_WwgcK5adSdg2FtkPAE3K3-E2V8tvRqkSeARrPm4tmWmLHViDGFhS8xEd36CyPrDjpJTcxqqCSXCJ7WIV3mOqbVjjhiGdmVnHUzDc_3Ahxr7XV0f-evwx_YWOyERaLI63LGFdjY-89IsxiAdn8_ouAe9miQ/w400-h270/large_burrow.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Note the wrinkles along the top margin of the burrow.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOWWrqCWe3sVDkYIaVHYoTAkChP2eRCV8gEwC5nI4_VjMJAggU4aNJvW0qoiVE2zdaFgZxs8snFOsjOP8EpxD8vaZPdGOrjoWo30GO9XOHrJS-OxClWYdSrbRhdAjUBajcsSDjygfabDgSmucVP4zBpqFajGCo8y8HDFDxk6iL1Fr9dlYbFwIUikGxEw/s1266/maybe_palaeosynapta.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="997" data-original-width="1266" height="315" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOWWrqCWe3sVDkYIaVHYoTAkChP2eRCV8gEwC5nI4_VjMJAggU4aNJvW0qoiVE2zdaFgZxs8snFOsjOP8EpxD8vaZPdGOrjoWo30GO9XOHrJS-OxClWYdSrbRhdAjUBajcsSDjygfabDgSmucVP4zBpqFajGCo8y8HDFDxk6iL1Fr9dlYbFwIUikGxEw/w400-h315/maybe_palaeosynapta.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
This is not the greatest photo, but a leaf-like pattern of surficial
marks is visible on the darkened surface.<br />
</td>
</tr>
</tbody>
</table>
<p>
These examples put me in mind of the
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqnSo1lij7S3Vnq4vTJyoq2K6eibE6a3gXEpGGp_VBDbopQXJGn29eJFi3F9qL9z_SjQFpIpPkd3_ckcxket-wEHgV9e-DzohCD321hET0X_nsnqSGzqfFPFYjotgfi6WO4Dg4q-oHYUUM/s1600/thing_cropped.jpg" rel="nofollow">wrinkled object</a>
included in
<a href="https://equatorialminnesota.blogspot.com/2019/10/compact-thescelosaurus-year-four.html" rel="nofollow">this post</a>, albeit not quite as well-preserved. I'm still leaning to some kind of lined
burrow akin to <i>Palaeosynapta</i>.<br />
</p>
<p></p>
<p><b>Others</b><br /></p>
<p>
Finally, here are a few more that I couldn't quite place firmly, although I do
have ideas.
</p>
<p></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkGs4yVMnJ9ZbMMtLzMnnBQ5wSg-iKjKy90IEM_ZcGrKKSkVcmsvwChVPyU59rXly5SPb9nKNl1gayv91Rxm7aIAPehMTYgEp8YCMukp4yLKKJVufzTSICsXfOnEE8zAHQNpSmQZkvVQD1XdDAZ0AqNY8UWNMD1wgHvJD1ctvDkE_YmdBmFt74dwD0Kg/s2416/carimona_thing.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1638" data-original-width="2416" height="271" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkGs4yVMnJ9ZbMMtLzMnnBQ5wSg-iKjKy90IEM_ZcGrKKSkVcmsvwChVPyU59rXly5SPb9nKNl1gayv91Rxm7aIAPehMTYgEp8YCMukp4yLKKJVufzTSICsXfOnEE8zAHQNpSmQZkvVQD1XdDAZ0AqNY8UWNMD1wgHvJD1ctvDkE_YmdBmFt74dwD0Kg/w400-h271/carimona_thing.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
I think I need to take a toothbrush for this one. There is clearly
something beneath the Carimona mud here; what I hope it is is a
<i>Carabocrinus</i> calyx, although if it is I don't think I want to
fully expose it.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhosF04pmCNau8TX56GFBc8cuz19KsgpjWQU43Elq0W8d0woi5o0SeXGSM2qftKnZOiOOzxpxhyM2RbiihcCjdF9YCBPVnr-H4g2PI-LNb3ug2EUVx40EteOUGve-GcEL-DXYcyg5wWOrKAMZuB4GtB3J87yzoeQZRRmE-kMXGjbAGnVbvFUNDA1mdc-w/s1872/ribbed.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1699" data-original-width="1872" height="363" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhosF04pmCNau8TX56GFBc8cuz19KsgpjWQU43Elq0W8d0woi5o0SeXGSM2qftKnZOiOOzxpxhyM2RbiihcCjdF9YCBPVnr-H4g2PI-LNb3ug2EUVx40EteOUGve-GcEL-DXYcyg5wWOrKAMZuB4GtB3J87yzoeQZRRmE-kMXGjbAGnVbvFUNDA1mdc-w/w400-h363/ribbed.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
I'm pretty sure this is just one of our more ornate snails.<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdo0AgN0Vl9iXalWu0Mf7TlYS2C4DkjJqfY6dpLMsjy2n06_asVfxB1Gj9oitk-jGyXQtW5R5fNKabUGA_Sk9Nl03uINqYKxz2tMEIwA1ZM4tmrG8Vtag5ObgWkTr5IIo1RWuF88I3baurHyc6hx1vGzlizk4JE7Zj055JV2owSt4nJjyA5yNPUm9Qlg/s1494/rippled.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1288" data-original-width="1494" height="345" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdo0AgN0Vl9iXalWu0Mf7TlYS2C4DkjJqfY6dpLMsjy2n06_asVfxB1Gj9oitk-jGyXQtW5R5fNKabUGA_Sk9Nl03uINqYKxz2tMEIwA1ZM4tmrG8Vtag5ObgWkTr5IIo1RWuF88I3baurHyc6hx1vGzlizk4JE7Zj055JV2owSt4nJjyA5yNPUm9Qlg/w400-h345/rippled.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
I saw
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKZ_MROlOksr5reRtHeoc0ENcOC_H-0Mh7pWNPw8WFQmIyUlSe_DrWD0NCfrYoGYXW0t5OEZSyF4QlZlhhWJUxPRfARmqE2FDA6EXGNv04ADY1lSjF5dyK6KfYlHOn-oGvs703M08C7_MsrD2FPsdnrTDf7zw6Xg-HdiC9EaOrgMWTysVRYMSwed3ZPg/s1992/weird_3.jpg" rel="nofollow">something kind of like this</a>
back in November, albeit more strongly ridged. My first instinct again
is a warped piece from a large trilobite (i.e., <i>Isotelus</i>).<br />
</td>
</tr>
</tbody>
</table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWsLPYXCQKexJY9AU0XFCiBLUZE08-CjUTJ6sEBW8_l5FuNMexVH7EFzcrMIV2ybVVOEXh5JO8Ha2iOjXq-UkPrIoaQ3saN6M0cNoqqV8uzRc2fRAfTqQl0qMBUMEdjM9S-jdHTL8AlCS4AAv8RRkDcbtSRGajULNnG4LDbk5Ck826MUfWmQhF9jJ6Rw/s1910/truncated_cone.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1782" data-original-width="1910" height="374" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWsLPYXCQKexJY9AU0XFCiBLUZE08-CjUTJ6sEBW8_l5FuNMexVH7EFzcrMIV2ybVVOEXh5JO8Ha2iOjXq-UkPrIoaQ3saN6M0cNoqqV8uzRc2fRAfTqQl0qMBUMEdjM9S-jdHTL8AlCS4AAv8RRkDcbtSRGajULNnG4LDbk5Ck826MUfWmQhF9jJ6Rw/w400-h374/truncated_cone.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
This is probably just a steinkern of a steep-sided low-coiled snail
(think like <i>Maclurites</i>), but it's also reminiscent of some kinds
of crinoid holdfasts (of course, it would then be an awfully big crinoid
for the Platteville).<br />
</td>
</tr>
</tbody>
</table>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-55944824512968276062023-05-28T10:00:00.001-05:002023-05-28T10:00:18.152-05:00Uŋčí Makhá Park Revisited, Part 1: Freeze-Thaw<p>
After I'd come across the
<a href="https://equatorialminnesota.blogspot.com/2022/10/strolling-on-magnolia-member-by-hidden.html" rel="nofollow">new exposures</a>
at
<a href="https://equatorialminnesota.blogspot.com/2022/11/quick-guide-to-fossils-at-unci-makha-park.html" rel="nofollow">Uŋčí Makhá Park</a>
last fall, I was very curious about how a Minnesota winter and spring would
treat them. After all, these were fresh, with no previous direct exposure to
snow, ice, and freeze-thaw cycles. Would they rapidly degrade, or were they
made of sterner material? Last week I had the opportunity to spend some
quality time at the park, in preparation for and leading a training session
for
<a href="https://www.nps.gov/miss/index.htm" rel="nofollow">Mississippi National River & Recreation Area</a>
seasonals (and if any of the participants happen on this post, hello! I hope
you had a good time!).
</p>
<p>
What were the results of this natural experiment? A few observations:
</p>
<p>
The Carimona Member of the Decorah (blue-gray upper interval), particularly
the blocks used as landscaping, suffered appreciably more than the Magnolia
Member of the Platteville (tan lower interval). I attribute this to the
greater shale content of the Carimona.<br /></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsM-9tPlzaW1Mk4pdXUgxPO--_EsJ34_HXErTEemEZWbhH7D7wI9DzD0oUPJ9IIw7ZuxvExKslI2ZuXYBWNF8JFgKIiegl9NwDEZix-NxUB_UH8HcrsnVW9QCZUl8s6xRAj4m0r5RDWVrUTwv1H3rrvGV_whSKGAl8m2gM8m_IR3HZ-AeHvASifMFUIA/s4765/carimona_magnolia_comparison.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3368" data-original-width="4765" height="283" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsM-9tPlzaW1Mk4pdXUgxPO--_EsJ34_HXErTEemEZWbhH7D7wI9DzD0oUPJ9IIw7ZuxvExKslI2ZuXYBWNF8JFgKIiegl9NwDEZix-NxUB_UH8HcrsnVW9QCZUl8s6xRAj4m0r5RDWVrUTwv1H3rrvGV_whSKGAl8m2gM8m_IR3HZ-AeHvASifMFUIA/w400-h283/carimona_magnolia_comparison.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
This is a pretty illustrative comparison. The blue-gray block on the
upper left is Carimona, and the tan block on the lower right is
Magnolia. The Carimona block's upper surface is littered with small
chips, while the only chips on the Magnolia block came from the Carimona
block. (Note also the large burrow on the Magnolia block.)<br />
</td>
</tr>
</tbody>
</table>
<p></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfSWYX9Fi7rSrjkXTatzGsnGzbmFz2DxQCStNnmhIRGLlZd1rbtzagvv-J9raKNDMUu16ObPTphgFfB955GCsFlYD1YeBt7vUPR5jOI3H2CjXafd_X1SMsH7qJH-CHcyjQCRGBMFQVG61d2Q5MVNzMXOeNyfP8DrloY7UX-mWUNlx2uP97YMhy5FNmJA/s5124/carimona_landscaping.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3218" data-original-width="5124" height="251" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfSWYX9Fi7rSrjkXTatzGsnGzbmFz2DxQCStNnmhIRGLlZd1rbtzagvv-J9raKNDMUu16ObPTphgFfB955GCsFlYD1YeBt7vUPR5jOI3H2CjXafd_X1SMsH7qJH-CHcyjQCRGBMFQVG61d2Q5MVNzMXOeNyfP8DrloY7UX-mWUNlx2uP97YMhy5FNmJA/w400-h251/carimona_landscaping.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
More Carimona landscaping showing exfoliation.<br />
</td>
</tr>
</tbody>
</table>
<p>This indicates that the Carimona blocks will weather faster than the Magnolia blocks; eventually, both lithologies will reach equilibrium with their new surroundings, but the "fucoidal" surfaces on the landscaping are going to go away faster than the shell beds.<br /></p><p></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqv-OUsDkdja-DV-mBrlbcWSe46nWnFKk6S_FRCaHF-cUBJtGlurOdtpgT3odOY9xrwGIsNqFFYJgh8Q3UMoBFAtEhAP1MiBLQfzy-qjXNopJU0juV1R_fqtpHjc92EBtnHOGNeNZci2jOvgXzSfhHKhh_TtPEcguMReO6v_fVErIywRI36mdtbs6KFQ/s5013/carimona_burrows_popping.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3087" data-original-width="5013" height="246" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqv-OUsDkdja-DV-mBrlbcWSe46nWnFKk6S_FRCaHF-cUBJtGlurOdtpgT3odOY9xrwGIsNqFFYJgh8Q3UMoBFAtEhAP1MiBLQfzy-qjXNopJU0juV1R_fqtpHjc92EBtnHOGNeNZci2jOvgXzSfhHKhh_TtPEcguMReO6v_fVErIywRI36mdtbs6KFQ/w400-h246/carimona_burrows_popping.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Note the burrows popping off the surface in some places.<br /></td></tr></tbody></table><p></p><p>It wasn't all smooth sailing for the Magnolia, though. Although many blocks and beds seemed fine, others had definite signs of damage.</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg26_sKRyRWrtjOnDqOaRplG-FL3gHBMZPJszdAwZxGg2djjEc1jP8ArhumOLH0VIacamv4mVyQhos6JeOpiCnP2n5cyrb0dfs3J5iXlQXUuJxAexhR3jcVVvziOYm5H2EUJ5dHwAJEaiwu6OhZAvN-evIPmj6N9ZFI8CafgunlSeekBIdYe8S7vXCl2w/s3663/magnolia_bed_breakup.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2819" data-original-width="3663" height="308" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg26_sKRyRWrtjOnDqOaRplG-FL3gHBMZPJszdAwZxGg2djjEc1jP8ArhumOLH0VIacamv4mVyQhos6JeOpiCnP2n5cyrb0dfs3J5iXlQXUuJxAexhR3jcVVvziOYm5H2EUJ5dHwAJEaiwu6OhZAvN-evIPmj6N9ZFI8CafgunlSeekBIdYe8S7vXCl2w/w400-h308/magnolia_bed_breakup.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Here a thin bed is breaking up.<br /></td></tr></tbody></table>
<p></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaWjm15YHTwUoa7AtpnZHW1cyr07yCM_9JS9OASgdsNimzxcBDtQPrAFRDyA5_Y9Rf9hs2xukRRMr50Y520Ik2t2fs_MiDLPTOPFksWxLyzIqrBBQloQBnkJdAOpyP-vWkzvszXMwfkjQOkmRrucONY5Ow1qubG2gjTLLwxQp0ULrYs7Pvm_HMmoblew/s3809/magnolia_shattered.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2852" data-original-width="3809" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaWjm15YHTwUoa7AtpnZHW1cyr07yCM_9JS9OASgdsNimzxcBDtQPrAFRDyA5_Y9Rf9hs2xukRRMr50Y520Ik2t2fs_MiDLPTOPFksWxLyzIqrBBQloQBnkJdAOpyP-vWkzvszXMwfkjQOkmRrucONY5Ow1qubG2gjTLLwxQp0ULrYs7Pvm_HMmoblew/w400-h300/magnolia_shattered.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">This isolated block appears to be shattered. (Colors are weird because when I took this photo, I'd forgotten to reset the lighting from tungsten bulbs.)<br /></td></tr></tbody></table><p>Unlike last fall, which was a time of drought, this spring we can also definitely see where the seeps are.<br /></p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix8Va-JQkKTkp-qqR7-bBmOCbobpsgaJ5qdAHsB-qg4oxXVt9IdT3Z7vm255kw2Gcm5LnarvWkasjOY1550PU0lFC9qTVLFGIRoQS-6qdi5_jTuipHqOOFPZ17J00oB3nZkYOE5Qakw_1m_AtKzhZiZkR6DU9BzCFXeSKBIhJiZUKTQHo6UvEGRbMQdw/s5152/seeps.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3453" data-original-width="5152" height="268" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix8Va-JQkKTkp-qqR7-bBmOCbobpsgaJ5qdAHsB-qg4oxXVt9IdT3Z7vm255kw2Gcm5LnarvWkasjOY1550PU0lFC9qTVLFGIRoQS-6qdi5_jTuipHqOOFPZ17J00oB3nZkYOE5Qakw_1m_AtKzhZiZkR6DU9BzCFXeSKBIhJiZUKTQHo6UvEGRbMQdw/w400-h268/seeps.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">And they're concentrated at the bentonite layers in the Carimona.<br /></td></tr></tbody></table><p>Many fossils and features came through without particular damage, though. I included <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiv4pTLsOT3JLz_l_9WPOeyT8V0aG_Gvpb73b7yOFEjWerhhdxQv93MM_Dwms_KtVxjHMZxtT_pL4pERt8IE5yRnt51gkQZjDByUktE8ADDqN0YLDWChTN-hBj2UnCQ514p91HJfbItPWUDIhEZSHjUXEdOlQFaQCwcLBTgRGgkJHmwcseALdU85qbew/s1996/vanuxemia.jpg" rel="nofollow" target="_blank">a photo</a> of a bivalve in the fossil guide post. Here it is last week:</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjK2NFT1ncPpwdr1lwCdy1EKtQzvnidq2sRgSK3mxkUyuyRirgwkKZ4bjeDm-0MQkmZI65zuZ74ndl9on3LNGGQNBsFW-7Zt1Z1iXHzI6bTgF_eWXLEhci3DyyZ_uJohBVxbEu7U_4LECLpA2_HkCkvEQnfkGcm9FhcAWU6tFWPtwtp5o8wA69CXxb2wg/s1905/vanuxemia_may.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1370" data-original-width="1905" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjK2NFT1ncPpwdr1lwCdy1EKtQzvnidq2sRgSK3mxkUyuyRirgwkKZ4bjeDm-0MQkmZI65zuZ74ndl9on3LNGGQNBsFW-7Zt1Z1iXHzI6bTgF_eWXLEhci3DyyZ_uJohBVxbEu7U_4LECLpA2_HkCkvEQnfkGcm9FhcAWU6tFWPtwtp5o8wA69CXxb2wg/w400-h288/vanuxemia_may.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Dare I say that it's "happy as a clam"? (Ignore the color balance differences.)<br /></td></tr></tbody></table><p>With that out of the way, did we find other fossils I hadn't seen in the fall? Well, of course! Tune in next week for some less-typical fossils!</p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-13031578217757838602023-05-07T11:37:00.000-05:002023-05-07T11:37:14.380-05:00Replacement of Fossils<p>
You might think that getting a shell or bone or wood chunk safely buried is
the tough part for fossilization, that once something's entombed in
sediment it's all smooth sailing. Burial is certainly important, but it's not the
end of the story. A lot of things can happen between deposition and exposure.
Pore spaces are filled with new minerals. Existing minerals are replaced.
Entire structures can be replaced, then lost. These changes all fall under
<a href="https://en.wikipedia.org/wiki/Diagenesis" rel="nofollow">diagenesis</a>. What exactly happens depends on things like the physical and chemical
structure of the object in question, temperature and pressure of burial, and
the chemical composition of the fluids in the sediment. Denser fossils like
teeth are less vulnerable to changes than more porous materials. The form of
calcium carbonate known as aragonite is less stable than calcite. Many
different minerals and mineraloids can get involved in the fun; for example,
there are
<a href="https://www.smithsonianmag.com/science-nature/scientists-and-miners-team-up-preserve-opalized-fossils-180972734/" rel="nofollow">opalized</a>
fossils and
<a href="https://en.wikipedia.org/wiki/Beecher%27s_Trilobite_Bed" rel="nofollow">pyritized</a>
fossils.
</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_L0EBszq8wT_WUd3xQHSJZIg_nuuRiejD1kwZBUIWvtqisJq5mcw10YUBPEnXWJWVTjQCNhiINFOe5h170J-5XVur701xZvRUZZ3Z7BztnWeyfsoFVLG-KmekPsGV7LTU1iyDJuHvOb5MNZy7SnuJFsjnqoGmOds5fDMlWZzwoEZbOCqTXpZVglRzwQ/s779/bivalve_mold_cast.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="487" data-original-width="779" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_L0EBszq8wT_WUd3xQHSJZIg_nuuRiejD1kwZBUIWvtqisJq5mcw10YUBPEnXWJWVTjQCNhiINFOe5h170J-5XVur701xZvRUZZ3Z7BztnWeyfsoFVLG-KmekPsGV7LTU1iyDJuHvOb5MNZy7SnuJFsjnqoGmOds5fDMlWZzwoEZbOCqTXpZVglRzwQ/w400-h250/bivalve_mold_cast.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Bivalve mold and internal cast (steinkern). Not pictured: bivalve
shell.<br />
</td>
</tr>
</tbody>
</table>
<p>Because silica and carbonate minerals are so abundant at typical surface
and near-surface temperatures and pressures, they are the minerals most
frequently involved. In Minnesota, we generally get <a href="https://en.wikipedia.org/wiki/Dolomitization" rel="nofollow">dolomitization</a>. This is
somewhat inconvenient, because dolomitization has a tendency to destroy fossils,
and even when it doesn't, it usually leaves behind molds and casts that aren't
as crisp as the original. It's a bit like replacing the Venus de Milo or
Michelangelo's David with nothing but 2x4 Lego bricks; you'll notice a
difference. Dolomitic replacement may give a fossil a quirky sparkly appearance
thanks to the dolomite rhombs, but that's about the only plus. Pervasive
dolomitization is why many fossils in the Platteville are gray with a sugary
appearance: you're actually looking at a natural mold or cast of the original in
dolomite.</p>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkHhj6cUW8dJ3uLjTlFXKJwlyBEV99lER5_G6QE3XhA5-5fyDFe00uPvmU4fUMjryRmNVZFROwOHRMYebbcgO_-7iEb6PCeOrQ7zVUdzYeZ998GA2hSBF7rnXt2jeQ91g5bvqId0iU0WVpZGsBfN3MKYFuapzkQfLZb-C5-leLGXsIIqC5Qcjo1-_fsw/s3640/dolomitized.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2319" data-original-width="3640" height="255" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkHhj6cUW8dJ3uLjTlFXKJwlyBEV99lER5_G6QE3XhA5-5fyDFe00uPvmU4fUMjryRmNVZFROwOHRMYebbcgO_-7iEb6PCeOrQ7zVUdzYeZ998GA2hSBF7rnXt2jeQ91g5bvqId0iU0WVpZGsBfN3MKYFuapzkQfLZb-C5-leLGXsIIqC5Qcjo1-_fsw/w400-h255/dolomitized.jpg" width="400" /></a>
</td>
</tr>
<tr>
<td class="tr-caption" style="text-align: center;">
Sometimes diagenesis gives you exotic, spectacular fossils, and
sometimes it gives you dolomite.<br />
</td>
</tr>
</tbody>
</table><br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<td style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimkp0U_rDMcY6XDx-aRR4DbUo43pdCOhnezfwyWPbeKkGoqMU0pZ_rC5_xxCHPTCojeqRS_5KU3I7SguvR64uU0AK7roioiY7X4A12mwYbozAazkX0uME9h5OsWgkzXP79hmkGKVmlkuyozOWk1K0wVjnKKo9GhRwzNiyldTpQ5kisquBdBxKJErSYsQ/s3055/replaced_nautiloid.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1999" data-original-width="3055" height="261" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimkp0U_rDMcY6XDx-aRR4DbUo43pdCOhnezfwyWPbeKkGoqMU0pZ_rC5_xxCHPTCojeqRS_5KU3I7SguvR64uU0AK7roioiY7X4A12mwYbozAazkX0uME9h5OsWgkzXP79hmkGKVmlkuyozOWk1K0wVjnKKo9GhRwzNiyldTpQ5kisquBdBxKJErSYsQ/w400-h261/replaced_nautiloid.jpg" width="400" /></a>
</td>
</tr>
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<td class="tr-caption" style="text-align: center;">
Although once in a while you get something to write home about; this is a nautiloid in the Science Museum of Minnesota collections with its internal structures replaced.<br />
</td>
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</table>
<p>I was inspired to write a note about this topic by a different kind of replacement. Someone reviewing one of my work projects commented on a type of replacement seen in some of the fossils, consisting of circular mineralizations. They informed me this was a kind of silicification known as <a href="https://en.wikipedia.org/wiki/Beekite" rel="nofollow">beekite</a>. This immediately twigged my memory banks, because I'd also seen it in photos of fossils from other work projects. Like dolomitization, it's not exactly faithful reproduction, although it can be aesthetically pleasing.<br /></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMTEr1jC57cbNYEt7d1-QiNnLELZDVVBiKxlgFzfQUsyWbFzhYG1TdPZP4N4bRhGLQa-9UdAYtG_TSUDhFo2jLyOaKXRkHa-nOZe1W48MjXb0rOfs7S4WHZhMK38FI9BTJysz6HUSSJZKUZeQCeIM_jA54biFRaXsOOaOv0RFXTYKBqXqIq6HcYUrxlw/s1934/beekitized.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1490" data-original-width="1934" height="309" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMTEr1jC57cbNYEt7d1-QiNnLELZDVVBiKxlgFzfQUsyWbFzhYG1TdPZP4N4bRhGLQa-9UdAYtG_TSUDhFo2jLyOaKXRkHa-nOZe1W48MjXb0rOfs7S4WHZhMK38FI9BTJysz6HUSSJZKUZeQCeIM_jA54biFRaXsOOaOv0RFXTYKBqXqIq6HcYUrxlw/w400-h309/beekitized.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">A beekitized (beekitified?) lower Permian brachiopod, central Kansas.<br /></td></tr></tbody></table>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-659253655801543842023-04-23T16:23:00.002-05:002023-04-23T16:23:57.449-05:00The Face of Diamantinasaurus (and some other body parts)<p>One of the things that was frequently missing from "<a href="https://equatorialminnesota.blogspot.com/p/your-friends-titanosaurs.html" rel="nofollow">Your Friends The Titanosaurs</a>" was heads. Sure, there were a fair number of lower jaws and braincases, but actual faces were few and far between. Skulls just don't seem to have stuck with the rest of the skeleton, and in general were not made of the sternest material in a titanosaur's body. (Bitey parts of the skull, yeah, those are more robust. Braincases, yeah, those are knots of bone. Stuff in between? Not so much.) Several entire continents are unrepresented by reasonably complete titanosaur skulls. We can now scratch Australia off that list, thanks to <a href="https://equatorialminnesota.blogspot.com/2019/03/your-friends-titanosaurs-10-diamantinasaurus-dongyangosaurus-dreadnoughtus.html" rel="nofollow"><i>Diamantinasaurus matildae</i></a>, as described in great detail by <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.221618" rel="nofollow">Poropat et al. (2023)</a>.</p><p>(...or can we? See below!) <br /></p><p><span></span></p><a name='more'></a><p></p><p>The specimen in question, AODF 0906 (Australian Age of Dinosaurs Museum, Winton, Australia), comes from rocks of the Winton Formation at Elderslie Station in central Queensland, northeastern Australia, and represents the fourth individual assigned to <i>D. matildae</i>. Known informally as "Ann", AODF 0906 was found in two clusters separated by a few meters, one including pelvic bones and several hind leg bones, the other including the cranial bones and a couple of leg bones and ribs. Overall the specimen includes a partial skull and lower jaws, a possible ceratobranchial bone (part of the <a href="https://equatorialminnesota.blogspot.com/p/blog-page_14.html" rel="nofollow">hyoid apparatus</a>), five sacral centra and several sacral processes, the centrum of the first caudal, four dorsal ribs, a chevron, the left pelvis and right ischium, both hind legs above the ankles, a fragment probably belonging to the right astragalus, all five right metatarsals, five pedal phalanges of right toes 3 and 4, and fragments. The partial skull is most complete on the left side, which includes the only premaxilla, maxilla, lacrimal, frontal, parietal, and ectopterygoid. Both postorbitals, squamosals, qudratojugals, quadrates, and pterygoids are present, along with the braincase (Poropat et al. 2023). The only major facial bones that appear to be missing are the nasals and jugals.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAEGnwigAEWMpKFtwNfqvCbyaBDlTRwRN-KFQXylGRmK7iInu8S0jJcZh4SYAY--KI6EI_mkSTc_0WHjn20z2VSehfzLt15fdckU8StjAc61pRSfI3a2SBt79GUgmm1AFKaCFkf1oo9fgKP-pS3mlxXS4jt2Luy8q9jgQrnD6Fc757UIVC3VJzloRF9Q/s642/diamantinasaurus_skull_reconstruction.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="642" data-original-width="527" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAEGnwigAEWMpKFtwNfqvCbyaBDlTRwRN-KFQXylGRmK7iInu8S0jJcZh4SYAY--KI6EI_mkSTc_0WHjn20z2VSehfzLt15fdckU8StjAc61pRSfI3a2SBt79GUgmm1AFKaCFkf1oo9fgKP-pS3mlxXS4jt2Luy8q9jgQrnD6Fc757UIVC3VJzloRF9Q/w329-h400/diamantinasaurus_skull_reconstruction.jpg" width="329" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">So as not to bury the lede any more than I already do: Poropat et al. (2023)'s overall reconstruction, clipped from Figure 3. Scale bar is 100 mm (3.94 in). <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.<br /></td></tr></tbody></table><p></p><p>Not only is the skull mostly complete, but this is also <i>D. matildae</i>'s first record of hind foot bones and, surprisingly, caudals (it seems like caudals are given away when new titanosaurs are named). <i>D. matildae</i> was already one of the best-represented titanosaurs, and AODF 0906 further solidifies that status. The species is a bit thin in total vertebrae, but we can't have everything.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQAi_TN0t1Z_3UmaZPuL4PN72kLKrrM5GbsNqDkfmPbwb6nzQDnoN5wtpTIurJjyQWimCuwGU43mN9PWOov-vT-9DWCNh5kG0pYNsPrjs2Ntl8dU4z4TjxDrCgUZqb2Jx-14BWA3ugm1KfziTcdpoPY5LykptNCzbDooxsulN9UYwxQor7ZnpLTr9ldQ/s2394/rsos221618f26.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2394" data-original-width="2057" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQAi_TN0t1Z_3UmaZPuL4PN72kLKrrM5GbsNqDkfmPbwb6nzQDnoN5wtpTIurJjyQWimCuwGU43mN9PWOov-vT-9DWCNh5kG0pYNsPrjs2Ntl8dU4z4TjxDrCgUZqb2Jx-14BWA3ugm1KfziTcdpoPY5LykptNCzbDooxsulN9UYwxQor7ZnpLTr9ldQ/w344-h400/rsos221618f26.jpg" width="344" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Because how often do we have titanosaur feet around here? Figure 26 from Poropat et al. (2023). Scale bar is 100 mm (3.94 in). <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.</td></tr></tbody></table><p></p><p>The first thing you might notice about the skull when taken as a whole is that it looks not unlike the skull of <a href="https://equatorialminnesota.blogspot.com/2020/07/your-friends-titanosaurs-27-ruyangosaurus-saltasaurus-sarmientosaurus.html" rel="nofollow"><i>Sarmientosaurus musacchioi</i></a>, particularly in <a href="https://equatorialminnesota.blogspot.com/p/blog-page_26.html" rel="nofollow">dorsal or ventral</a> view, where the muzzle ends with a blunt point. This is not entirely unprecedented, as both species had previously been proposed as members of the clade Diamantinasauria. In side view <i>D. matildae</i> is not as quite as well-preserved, so there is some wiggle room about the exact profile of the face (it's been given a somewhat diplodocid-like profile, a bit more elegant than the "archless <i>Giraffatitan</i>" applied to <i>S. musacchioi</i>). Both, though, have long tooth rows and rather large teeth, and don't have as extreme of an arch in the jugal-quadratojugal area as later titanosaurs. <i>D. matildae</i> had four teeth per premaxilla, nine per maxilla, and 11 per dentary, a few teeth fewer than <i>S. musacchioi</i> for the maxilla and dentary. The two skulls are similar in size, with the <i>D. matildae</i> skull being slightly larger than the <i>S. musacchioi</i> skull. Dimensions are estimated as 500 mm long versus 250 mm wide versus at least 210 mm tall (19.7 by 9.84 by 8.27 inches) (Poropat et al. 2023).</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_ekSwa6rrdTPkMxjSil5Ng-5gFyJuEATb947yGvpaNMs-5hoyFLOAEsqG0bNE5_pY9PvoqAV5uWlY-GkogeIQgvm30HqJ81-oVABCeZeikG6TDm4JlpqN39I-lKV11wgTVFXuUd1asG7NwIkOam4crDxwPunWXQre0JyIiEf6CjlPVcbpcs0QUquewQ/s2394/rsos221618f03.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2394" data-original-width="2057" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_ekSwa6rrdTPkMxjSil5Ng-5gFyJuEATb947yGvpaNMs-5hoyFLOAEsqG0bNE5_pY9PvoqAV5uWlY-GkogeIQgvm30HqJ81-oVABCeZeikG6TDm4JlpqN39I-lKV11wgTVFXuUd1asG7NwIkOam4crDxwPunWXQre0JyIiEf6CjlPVcbpcs0QUquewQ/w344-h400/rsos221618f03.jpg" width="344" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The entirety of Figure 3 (<a href="https://royalsocietypublishing.org/doi/10.1098/rsos.221618" rel="nofollow">which see</a> for lengthy caption). <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.</td></tr></tbody></table><p></p><p></p><p>A secondary question from the publication is less easily answered: is <i>Diamantinasaurus</i> (and other diamantinasaurs) a titanosaur? Poropat et al. present two analyses, one that has Diamantinasauria near the base of Titanosauria (equal weights), and another that has it a couple of notches outside of Titanosauria (extended implied weights). Fair enough: we're looking at something that's just inside or just outside, which is reasonable on the basis of age and the shape of the skulls of <i>Diamantinasaurus</i> and <i>Sarmientosaurus</i>. <i>Diamantinasaurus</i> shows some features that are not expected for a titanosaur, such as a sacrum with only five vertebrae and an amphicoelous first caudal. It also had three phalanges in the third toe, which is not extremely common among titanosaurs but not unknown (<a href="https://equatorialminnesota.blogspot.com/2019/04/your-friends-titanosaurs-11-drusilasaura-elaltitan-epachthosaurus.html" rel="nofollow"><i>Epachthosaurus sciuttoi</i></a>).<br /></p><p>The problem, ultimately, is not <i>Diamantinasaurus</i>'s fault; it's doing the best it can. In terms of material and overall coverage, it's doing better than 95% of titanosaurs. The problem, obviously, is everyone else. Complete sacra, good feet, and nearly complete skulls are hard to come by. I've got a spreadsheet that depicts which bones or bone groups are known for which titanosaurs. You probably don't need to hear it from me, but there are a lot of empty cells. How many complete sacra are known for other basal titanosaurs? Well, there's one for <i><a href="https://equatorialminnesota.blogspot.com/2019/03/your-friends-titanosaurs-10-diamantinasaurus-dongyangosaurus-dreadnoughtus.html" rel="nofollow">Dongyangosaurus</a></i> (if you are confident that it is in fact a titanosaur) and <i><a href="https://equatorialminnesota.blogspot.com/2019/10/your-friends-titanosaurs-17-malawisaurus-mansourasaurus-maxakalisaurus.html" rel="nofollow">Malawisaurus</a></i> (if the sacrum in fact belongs to <i>Malawisaurus</i>). How many feet are known for other named basal titanosaurs? (crickets chirp) Admittedly, there are a few sacra and feet on the other side of the line, but you get the idea. More to the point, how many sacra, feet, and skulls are known for <i><a href="https://equatorialminnesota.blogspot.com/2018/08/your-friends-titanosaurs-3-andesaurus-antarctosaurus-argentinosaurus.html" rel="nofollow">Andesaurus</a></i>, the gatekeeper of Titanosauria? No dice: you get two (2) sacral vertebrae, no (0) bones of the hind feet, and no (0) head. This is, to put it mildly, inconvenient; basal titanosaurs really need to step up their game. Poropat et al. (2023) concluded by leaning in the "titanosaur" camp ("probably" versus "possibly" outside).<br /></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikFygXEnVPTbOXBIrS7-LFk9c8ngF4XtaZKxG2U9DVbHmB1n_MzdF_IJzhjkplaJsWLJYxLg2FsrEH2FbP_i8GuBDTroU9_-9nhFH5nne07Bh_8EasWyR-xG9FHkQcq5P9BYw4FnhH4vx_iruXT_Gt5oT4BgbiJIAB5MJyVQ9s93QmupKOVvg_0asN7A/s996/diamantinasaurus_sacrum.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="344" data-original-width="996" height="139" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikFygXEnVPTbOXBIrS7-LFk9c8ngF4XtaZKxG2U9DVbHmB1n_MzdF_IJzhjkplaJsWLJYxLg2FsrEH2FbP_i8GuBDTroU9_-9nhFH5nne07Bh_8EasWyR-xG9FHkQcq5P9BYw4FnhH4vx_iruXT_Gt5oT4BgbiJIAB5MJyVQ9s93QmupKOVvg_0asN7A/w400-h139/diamantinasaurus_sacrum.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The mystery of the undersacralized titanosaur? Clipped from Figure 22 in Poropat et al. (2023), scale bar 200 mm (7.87 in). <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.</td></tr></tbody></table><p></p><p>Reminder: I'll be giving a talk for the Geological Society of Minnesota
on Monday, May 8: "<a href="http://gsmn.geosocmn.org/node/9970" rel="nofollow">Snorkeling at Shadow Falls: Fossils of Minnesota</a>". Non-members are welcome!</p><p>References</p><p>Poropat, S. F., P. D. Mannion, S. L. Rigby, R. J. Duncan, A. H. Pentland, J. J. Bevitt, T. Sloan. and D. A. Elliott. 2023. <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.221618" rel="nofollow">A nearly complete skull of the sauropod dinosaur <i>Diamantinasaurus matildae</i> from the Upper Cretaceous Winton Formation of Australia and implications for the early evolution of titanosaurs</a>. Royal Society Open Science 10(4):article 221618. doi: <a href="https://doi.org/10.1098/rsos.221618">https://doi.org/10.1098/rsos.221618</a>.<br /></p>Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0tag:blogger.com,1999:blog-6574000839639433662.post-31184520388566363602023-04-10T21:53:00.001-05:002023-04-10T21:53:13.188-05:00The Conulariid Interior<p>
Today we check in with one of the more unusual members of Paleozoic seafloor
communities:
<a href="https://equatorialminnesota.blogspot.com/search/label/conulariids" rel="nofollow">Conulariida</a>. The "<a href="https://equatorialminnesota.blogspot.com/2014/08/the-amazing-four-sided-herringboned-ice.html" rel="nofollow">four-sided herringboned ice cream cones</a>" still hold many mysteries (including the mystery of the whereabouts of
<a href="https://equatorialminnesota.blogspot.com/2018/12/ordovician-updates.html" rel="nofollow">George Sinclair's collection</a>; I'd still be interested in knowing more about that!). One of the major
mysteries has been what exactly the soft parts of the animal looked like; if
we knew that, we'd know a lot more about how conulariids are related to other
animals, how they fed, how they looked, etc. It's generally assumed they are
some kind of cnidarian (along with corals, jellyfish, sea anemones, and so
on). Wikipedia has them potentially aligned with Staurozoa, which today is
represented by
<a href="https://en.wikipedia.org/wiki/Stauromedusae" rel="nofollow">stalked jellyfish</a>
(worth looking up if you've never heard of stalked jellyfish).
</p>
<p>
A cnidarian identity would imply stinging tentacles, but these have never been
firmly identified. Soft parts in general are not particularly well-known for
conulariids, which makes sense because preserving the soft parts of cnidarians
is not something that just happens as a matter of course. (We could use a late Paleozoic
amber-producing coastal forest that was flooded by a storm that dredged up all
kinds of marine organisms.) There were some potential finds in the 1980s, as
discussed in Babcock and Feldman (1986a) and
<a href="https://link.springer.com/article/10.1007/s12542-023-00649-7" rel="nofollow">Sendino et al. (2023)</a>
(see
<a href="https://www.biodiversitylibrary.org/page/52460847" rel="nofollow">Figure 30</a>
in Babcock and Feldman 1986b for internal casts and x-ray image of a conulariid's putative guts). Recently,
Sendino et al. (2023) have applied X-ray micro-Computed Tomography (μCT) to a
collection of well-preserved Pennsylvanian-age conulariids from the Wewoka
Formation of Oklahoma and the Finis Shale Member of the Grand Formation of
Texas.
</p>
<p>
What can μCT see in a conulariid? First off, it can see the concealed end of
one conulariid partially within another conulariid. This is a good sign as a
sanity check because we can confirm it can discern something that obviously
should be there. With that encouraging information in mind, what else is
there?
</p>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOQX9Ggva_ZvUbOfXLEmouMC5sZeWZENeCFmtfnbN2PGdDLisS3pmMGDQuPONZ7P2PI44c8DSWBEflSP2Qxc-0UIGeGS4tf4VvCDCSLEPYmYRagf_uOyk8gNDnMO3mHHlRsvvCpuzHyBoMjlZKkoBjo_IeoLU74vVw9Q2qCs2hxW7dn7kopL8LsNpyUg/s1500/conulariid_in_conulariid.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1136" data-original-width="1500" height="303" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOQX9Ggva_ZvUbOfXLEmouMC5sZeWZENeCFmtfnbN2PGdDLisS3pmMGDQuPONZ7P2PI44c8DSWBEflSP2Qxc-0UIGeGS4tf4VvCDCSLEPYmYRagf_uOyk8gNDnMO3mHHlRsvvCpuzHyBoMjlZKkoBjo_IeoLU74vVw9Q2qCs2hxW7dn7kopL8LsNpyUg/w400-h303/conulariid_in_conulariid.jpg" width="400" /></a>
</td>
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<td class="tr-caption" style="text-align: center;">
<a href="https://link.springer.com/article/10.1007/s12542-023-00649-7/figures/4" rel="nofollow">Figure 4</a>
in Sendino et al. (2023); it's always good to see what you *ought* to
see.
<a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.
</td>
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</table>
<p></p>
<p>
Sendino et al. (2023) found "longitudinal bundles" in many of their specimens,
i.e., oriented apex–aperture. The authors interpreted these as muscles for
closing the flaps of the aperture. (This tells us a few things about the
muscular and nervous systems of conulariids.) In some examples there was also
an internal structure they interpreted as a possible gastric cavity. In other
specimens, the internal sediment was clearly replaced, for example by sand, or
contained other fossil material such as forams or a tiny drilled brachiopod.
The internal sediment of some specimens appears to have been disrupted by
later burrowing. A number of the conulariids also show scars from external
attacks (conulariids seem to have been easy targets). The article, which is
freely available, is heavily illustrated with μCT images, followed up by a
series of supplementary files of large images.<br />
</p>
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<tbody>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilL5W1fdEyd-FKGgrV_EmxPIVjneM_N8rCUq40mCBmAxmceAW27rgaiRCBQzCoeq31uAL1zgQZHZsW_pHJPIdzBsTULxWz567PS1qyDkiUKWYV8Yzi6XBG9D3iLvCSBkhzhdRj0lSC1p8kFg7taPqFY1tXrYAmf4doiRmHuFhpsACT4as-20FodhMH6A/s1381/conulariid_guts.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1381" data-original-width="827" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilL5W1fdEyd-FKGgrV_EmxPIVjneM_N8rCUq40mCBmAxmceAW27rgaiRCBQzCoeq31uAL1zgQZHZsW_pHJPIdzBsTULxWz567PS1qyDkiUKWYV8Yzi6XBG9D3iLvCSBkhzhdRj0lSC1p8kFg7taPqFY1tXrYAmf4doiRmHuFhpsACT4as-20FodhMH6A/w240-h400/conulariid_guts.jpg" width="240" /></a>
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And this is their basic interpretation (<a href="https://link.springer.com/article/10.1007/s12542-023-00649-7/figures/13" rel="nofollow">Figure 13</a>).
<a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow">CC BY 4.0</a>.
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<p></p>
<p>
In other business: I'll be giving a talk for the Geological Society of Minnesota
on Monday, May 8: "<a href="http://gsmn.geosocmn.org/node/9970" rel="nofollow">Snorkeling at Shadow Falls: Fossils of Minnesota</a>". Non-members are welcome!
</p>
<p>References</p>
<p>
Babcock, L. E., and R. M. Feldmann. 1986a.
<a href="https://www.biodiversitylibrary.org/page/52460752" rel="nofollow">Devonian and Mississippian conulariids of North America. part A. General
description and <i>Conularia</i></a>. Annals of the Carnegie Museum 55:349–410.
</p>
<p>
Babcock, L. E., and R. M. Feldmann. 1986b.
<a href="https://www.biodiversitylibrary.org/page/52460816" rel="nofollow">Devonian and Mississippian conulariids of North America. part B.
<i>Paraconularia</i>, <i>Reticulaconularia</i>, new genus, and organisms
rejected from Conulariida</a>. Annals of the Carnegie Museum 55:411–479.
</p>
<p>
Sendino, C., B. Clark, A. C. Morandini, T. Salge, M. Lowe, and W. Rushlau.
2023.
<a href="https://link.springer.com/article/10.1007/s12542-023-00649-7" rel="nofollow">Internal conulariid structures unveiled using µCT</a>. PalZ (2023). doi:<a href="https://doi.org/10.1007/s12542-023-00649-7" rel="nofollow">https://doi.org/10.1007/s12542-023-00649-7</a>.
</p>
Justin Tweethttp://www.blogger.com/profile/01792470288586894872noreply@blogger.com0