Afton graptolites revisited

There are two great lost fossil sites in the Twin Cities area. (The Brickyards don't count; they're not lost, they just aren't open to collection.) One is the Johnson Street Quarry, where workers cut into a bed in the Hidden Falls Member of the Platteville Formation that had unusually abundant echinoderms. As described in Sloan et al. 1987: 200, "Sardeson mined out a spot in this unit in the old Johnson Street Quarry in Minneapolis (now filled with garbage, and covered with Interstate 35) that produced about 20 specimens of the starfish Protopalaeaster narrawayi, several specimens of the crinoid Cremacrinus arctus (Fig. 16.2), edrioasteroids, cystoids, brachiopods, bryozoans, molluscs, and graptolites." This is slightly out of date; instead of a dump, there's now a Quarry Shopping Center with a Cub Foods, Home Depot, and Target, although even with all those options you can't get an edrioasteroid there anymore. Regardless of the exact character of the overburden, it seems unlikely that anyone will be doing any paleontological follow-up there anytime soon. The other locality is the Afton graptolite locality in the St. Lawrence Formation. We already had a post on why this locality was important; what I'm curious about is where exactly it was. A locality, even if "lost", had to have been *somewhere*, and apart from the scientific and historic interest, there very well could be similar fossils in rocks nearby. Indeed, Hughes and Hesselbo (1997) reported graptolites in the lowest strata of the St. Lawrence Formation in their Afton section, where collection may have postdated the road work that destroyed the classic location. For some reason, despite its “classic” nature, nobody ever saw fit to just put a pin on the map. What clues do we have?

Secrets of "Secrets Of The Dinosaur Mummy", or: How I Got An IMDb Entry

A few days back I did something I hadn't done since 2008: I watched "Secrets of the Dinosaur Mummy". This was mostly because I had a friend over and wanted to show her what the Leonardo thing was all about, along with my minor claim to small-screen fame. Obviously going that road brought out the memories, so I thought maybe it was time to have a look back. Getting the "Truth in Advertising" out of the way up-front: I don't actually have a lot of secrets about "Secrets of the Dinosaur Mummy", but I do know a title when I see one!

It turned out to be unexpectedly difficult to get a good photo of the cover, being moderately glossy and dark, but you get the idea. One of these two blurbs is good for a chuckle, given the prominence of the speaker in the documentary.

Uŋčí Makhá Park 2024: another winter, more echinoderms

Two years after opening, Uŋčí Makhá Park can be considered a paleontological gem in the Twin Cities. With its Magnolia Member bedding planes, side cuts through the Magnolia and Carimona, easy access, and lack of vehicle traffic, it's nigh-on perfect for getting in touch with St. Paul as it was about 454–453 million years ago. It's kind of like our own Carnegie Quarry wall, except it's tiny marine invertebrates rather than dinosaurs, it probably wasn't planned, and you can walk right out over it. It's always fun to get to spend time there for work, and like last year, I got the opportunity to assist with a training session for Mississippi National River & Recreation Area seasonals there. Then, of course, I just had to make a quick return trip later to follow up on some things we'd seen.

Uŋčí Makhá Park Revisited, Part 2: Further Fossils

We're now up to the fourth entry in a completely unexpected series 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.

Quick Guide to Fossils at Uŋčí Makhá Park

So I went back to Uŋčí Makhá Park last weekend and spent a couple of hours taking photos of fossils, because it makes such an ideal place to see the upper Platteville fauna. After all, a winter of freezes and thaws may not leave these new exposures looking as nice as they do now. Here's a quick guide to what can be seen there. (Let's see how many photos I can squeeze into one post, and how many species I can misidentify!)

Determining where you are stratigraphically

First of all, I'd just like to reiterate the stratigraphy. Most of the vertical extent is in the Magnolia Member of the Platteville Formation, with the upper part composed of the Carimona Member of the Decorah Shale. I'm thinking more or less the entire extent of the Carimona is exposed, based on thickness; at any rate the next thing up would be the shaly part of the Decorah, and there isn't a trace of it to be seen. I'm suspicious because the difference is just so darn clear, but at this site there is an unmistakable color change between the two units: the Carimona is the upper blue-gray interval and the Magnolia is the light tan-gray interval below. The Deicke K-bentonite is the lower and thicker of the two bentonite gaps in the Carimona. (Note that the Carimona is sometimes supplemented or replaced by landscaping, but this is pretty obvious.) As you walk from south to north, the "floor" goes up stratigraphically, so it's not all one bedding plane but a gently rising series of planes, until by the exit you're close to the color change.

The color change is quite evident here. The Deicke K-bentonite is the cut-in about halfway up the blue-gray Carimona (above the scale bar in the center of the photo).

Here we've gone north, and the floor has risen. The Deicke is still the seam in the middle of the blue-gray rocks.

Your Friends The Titanosaurs, part 36.2: Coming Attractions (Europe and South America)

Here we go: Apart from next month's wrap-up (and anything that gets named before then), this is the last time down the titanosaurian rabbit hole. We're going to visit the unnamed titanosaurs of Europe and South America, complementing the visit last time to the rest of the world. Some of the best examples are in this post, such as MAU-Pv-LI-595, MAU-Pv-AC-01, and MUCPv-1533, all from the vicinity of Rincón de los Sauces/La Invernada.

Note: This is another long one. On the other hand, it's split into many paragraph-sized chunks, so it's good for skipping around.

Your Friends The Titanosaurs, part 36.1: Coming Attractions (outside of Europe and South America)

Here we have a few of the many, many unnamed and/or undescribed titanosaurs. Some of their common habitats are abstracts, dissertations, press releases, and offhand comments in publications. Sometimes they're the subject of a paper describing some particular anatomical topic, or a geographic range extension. In other cases they're among five different morphotypes in a bonebed, and you can only hope that this pans out, because otherwise there's no negotiating with a von Huene puzzle. All the while you grit your teeth because you despair of ever seeing the really notable specimens published, especially so long as there's a theropod knuckle left to be described...

Anyway, this is not quite like "Coming Attractions in Dinosauria", which was based primarily on unnamed species with nicknames in long use. This is more like the original Addendum II in "The New Dinosaur Dictionary", except with specimen numbers and more references. It is certainly not exhaustive, and would take a lot more than a few weeks to make so. I am omitting embryonic forms (note that titanosaur nests have been found in several areas, including Argentina, India, and Spain), tracks, and named forms that need further description (Ampelosaurus, Futalognkosaurus, etc.). I've organized this by continent, and then by country; it turns out that if a country has terrestrial Cretaceous rocks, there is an excellent chance it has titanosaurs. Because of the sheer number of entries, I opted to split the post, with Europe and South America to come later.

I don't know if this will impress anyone, but I had a lot of fun writing this post.

Your Friends The Titanosaurs, part 34: Titanosaurs of Yesterday

There are a few taxa of interest that haven't yet been covered. They include: 1) "historical titanosaurs", the kind you might stumble across in a 1980s dinosaur dictionary; 2) poorly known species regarded as titanosaurs mostly on the circumstantial evidence of time and place, without the anatomical evidence to back up a classification; 3) species that have turned up in Titanosauria once or twice during the cladistic era (mid-1990s to the present) but are not currently or generally regarded as titanosaurs; and 4) species that appear to have been near Titanosauria and sometimes hop the line in analyses, but usually are found outside. This post is for the first three varieties. We've got 15 in the queue, so as you can image I'm not going to go into a great deal of detail.

Curiously, most of McIntosh's "Sauropoda incertae sedis" from the first edition of The Dinosauria show up on this page: "Pelorosaurus" becklesii (=Haestasaurus), Mongolosaurus, Austrosaurus, and Aepysaurus (=Aepisaurus), plus a shout-out to "Apatosaurus" minimus. The only ones not here are "Morosaurus" agilis (now described as a rebbachisaurid [2021/04/02: no, dicraeosaurid; do this long enough and they all run together], Smitanosaurus), and Campylodoniscus, which was previously featured. This says something about quasi-titanosaurs, but I'm not sure what. The taxa also skew old, with many of Early Cretaceous or even Late Jurassic age, suggesting it's harder to get a handle on putative early titanosaurs. Unsurprisingly, many of them are dubious, albeit in all kinds of ways: from garden-variety causes like too little material, to "unavailable for study due to being destroyed by monsoons", to "the osteoderms turned out to be ribs", to "the original describer thought a pile of caudals from several sites separated by miles belonged to one individual", to "actually filled mollusk borings".

As a reminder, because the terms come up several times, Titanosauriformes is the clade made up of the most recent common ancestor of Brachiosaurus and Saltasaurus plus all of its descendants, and Somphospondyli is the clade made up of all sauropods more closely related to Saltasaurus than to Brachiosaurus.

Your Friends The Titanosaurs, part 33.3: Alamosaurus of Texas and Mexico?

Having visited New Mexico and Utah (with side trips to Wyoming and Montana), we come now to more southerly Alamosaurus, concentrated in the Big Bend region of Texas. After a slow start Big Bend titanosaurs have attracted a lot of study, with numerous publications over the past quarter-century. There are also some less well-documents reports from elsewhere in Texas and across the border in Chihuahua, Mexico. We also have a little more on the question of whether or not we're dealing with just one species, and Tyrannosaurus makes yet another cameo.

This post marks the end of the main part of "Your Friends The Titanosaurs" (I can hardly believe it!) although we do have a few things to follow up with before calling it closed.

A view of the Perot Museum of Natural History mount (Dallas, Texas) emphasizing the neck. The original neck vertebrae are visible near floor level behind the torso of the mount. In the lower right a Tyrannosaurus rex has second thoughts. Photo by Louis Tanner from Garland, TX, USA, CC-BY-2.0, via Wikimedia Commons.

Your Friends The Titanosaurs, part 33.1: Alamosaurus of New Mexico

The time has come to deal with the one and only named North American titanosaur, the redoubtable Alamosaurus sanjuanensis. You may remember that in the very first post of this series, I mentioned I was skipping Alamosaurus for the moment. I was waiting on it because I was concerned that it might suffer a taxonomic detonation at any time, so I thought I'd hold off as long as possible. Such has not happened (yet).

I originally thought I could get away with one post. This was before I actually sat down to the substantial body of literature on A. sanjuanensis. I ended up going through around 60 references, with another few I haven't been able to find yet due to them being dissertations or conference ephemera or some such. This number does not count the many, many cameo performances for our guest, which turns up in almost every paper dealing with titanosaurs, being cited for anatomical comparisons or included in a phylogeny. This is what comes of 1) a century of publications; 2) being the only named titanosaur in the paleontological hotbed of North America; 3) shouldering the burden of breaking the Great North American Sauropod Hiatus™; 4) being (seemingly) represented by lots and lots of specimens; and 5) having a wide geographic distribution.

In the interests of sanity (both yours and my own dwindling reserves) and length, I'm therefore splitting the material over multiple posts for February, going by geography. There are three natural geographic divisions (New Mexico, Utah, and Texas), plus some miscellaneous records of interest that should fit under that format (Wyoming and Montana with Utah, and Mexico with Texas), so I think three posts will take care of things. We'll start off with New Mexico, because chronologically that's where the story begins.

(Of course, in March someone will publish a paper that will undo everything.)

Your Friends The Titanosaurs, part 27: Ruyangosaurus, Saltasaurus, and Sarmientosaurus

Today on "Your Friends The Titanosaurs", it's a giant enigma (Ruyangosaurus giganteus), a much smaller and much better known titanosaur that also turns out to have its enigmatic side (Saltasaurus loricatus), and a good old-fashioned titanosaur skull taxon (Sarmientosaurus musacchioi), plus special guest stars Noasaurus and the Rincón de los Sauces titanosaur! (If anything seems odd, formatting-wise, it's because this is my first structurally complex post since Blogger changed to a new interface, and I'm dealing with a couple of things.)

Kholumolumo ellenbergerorum and "Thotobolosaurus"

With the twin unofficial missions of Equatorial Minnesota to cover Elliot Formation "prosauropods" and find out what happened to unpublished dinosaurs of the past, it was imperative that Kholumolumo ellenbergerorum receive a post. Before we get into the actual science of K. ellenbergerorum, though, let's step back through the mists of time. First we'll stop off in the far-off world of 1985.

You've just gotten the Normanpedia (Norman 1985) and are busy committing it to memory. On page 97, in the "Dubious" section of the list of prosauropod genera, is Thotobolosaurus. It doesn't ring a bell, so you pull out "A Field Guide to Dinosaurs" (Lambert 1983). It shows up on page 104, as a "roccosaurid" with Riojasaurus and something called Roccosaurus, which wasn't in the Normanpedia. "Roccosaurids" apparently have "unusually sharp fangs and an especially strong joint linking hips with the backbone", but might actually be melanorosaurids. This last bit just ends up being confusing because (stepping outside of 1985 for a moment) "A Field Guide to Dinosaurs" was caught up in the contemporary fad for lumping all kinds of prosauropods, so Melanorosaurus is sunk into Euskelosaurus. Anyway, Thotobolosaurus is "a big prosauropod that lived in early Late Triassic Lesotho, southern Africa." Okay, sure. Does "The New Dinosaur Dictionary" (Glut 1982) have anything more, and can it explain what exactly is a Roccosaurus?

Your Friends The Titanosaurs, part 20: Neuquensaurus, Normanniasaurus, and Notocolossus

The entrants this week come with both notability and downsides. Normanniasaurus genceyi is one of the few well-established Early Cretaceous titanosaurs, and Notocolossus gonzalezparejasi is one of the largest known titanosaurs. However, both are known from rather limited material to date. Neuquensaurus, on the other hand, has had no shortage of material referred to it, but is a historical mess. So far it has escaped the fate of Argyrosaurus superbus, Laplatasaurus araukanicus, and Titanosaurus indicus, historically significant names that have been re-analyzed and cut down to just a type specimen. There are still questions surrounding Neuquensaurus, but at least there are multiple specimens that can be assigned to it.

Hunting the history of the Channel Islands mammoths

My visit to Santa Rosa Island back in June was just part of a larger project on Channel Islands National Park, for which I've been gathering information, researching, and writing for a number of months. Part of that work is summarizing the history of paleontological investigations, which go back well into the 19th century, and one of the most important parts of that is the history of mammoth finds on the islands. As often happens the story turned out to involve many more parts than I thought.

Your Friends The Titanosaurs, part 15: Lirainosaurus, Lohuecotitan, and Loricosaurus

This and the next few posts are going to be spending significant time outside of the South American titanosaur stronghold. Only Loricosaurus scutatus will be representing South America this time, with the other two slots filled by the unusually small Lirainosaurus astibiae and larger Lohuecotitan pandafilandi, both from the Upper Cretaceous of Spain.

This map, part of Figure 1 from Díez Díaz et al. (2011), shows the distribution of European titanosaur cranial material, but also happens to show the discovery locations of Lirainosaurus astibiae, Lohuecotitan pandafilandi (Lo Hueco), and species assigned to Magyarosaurus, which is coming up quickly. CC-BY-4.0.

Your Friends The Titanosaurs, part 13: Isisaurus, Jainosaurus, and Jiangshanosaurus

We take a brief break from South America and journey to India and China this time. Conveniently, two of the three most significant Lameta Formation titanosaurs have come up (the other is venerable Titanosaurus indicus, which isn't for a while yet). On the other hand, that does mean we're going to be spending a lot of time trying to figure out how many sauropods can dance on a hill named Bara Simla, in the company of Friedrich von Huene and Charles Matley.

Titanosaur osteoderms: characteristics

Now that we've had a look at the background and history of study for titanosaur osteoderms, we can get into the nitty-gritty of their anatomy and where they were positioned on the body. It turns out there's still quite a lot we don't know about these structures.

Titanosaur osteoderms: introduction and history of study

One of the most notable aspects of titanosaurs is the presence of bony armor in at least some species. It's where we get Lithostrotia ("inlaid with stones"), after all. Armored titanosaurs have been hinted at since the 1890s and accepted since the 1980s, but despite forty years of publications and many finds across the world, there are still many things we do not know about titanosaur armor. Even the position on the body is mostly a matter of inference.

I'd had the idea of looking at titanosaur osteoderms and ossicles (the technical terms) in more detail since poster Ornithopsis commented on them following the very first "Your Friends The Titanosaurs" post. Originally I thought I could do it in one post, but after fourteen pages of notes and forty-plus references, this seemed perhaps overly ambitious. Therefore, this post will focus on the history of study (and a healthy bibliography, for those of you collecting papers), and a couple of future posts will cover more detailed descriptions, location on the body, distribution in time, space, and the titanosaur family tree, and functions. If you want spoilers...

Your Friends The Titanosaurs, part 8: Bonitasaura, Borealosaurus, and Brasilotitan

And so we reach Part 8, otherwise to be known as "Bonitasaura and these other two." Bonitasaura is one of the best-known sauropods, even if it isn't quite a household word, and also has some unusual jaw features going for it. Brasilotitan has some of the same jaw features, but is not known from nearly as much material and came along several years later. Borealosaurus has an uncertain grip on Titanosauria, and gripping things takes some creativity when you have either no fingers or just nubs.

Decorah gastropods (and some things that look like gastropods)

The snails* of the Decorah Shale are a lesser component of the fauna than bryozoans, brachiopods, or crinoids. My personal experience is that snails are uncommon except for certain beds, which feature abundant and diverse snails. One of these beds is perhaps 20 ft (6 m) above the top of the Carimona in St. Paul; this bed produced the plate in the "Equatorial Minnesota" box near the top of the page. For whatever reason, this bed also hosts abundant trilobite pieces, particularly of Eomonorachus. There's probably a facies thing going on, such that the original depositional environment was favorable to snails and trilobites; it's not quite as stark as, say, McKee (1938)'s mollusk and open marine facies of the Kaibab Formation (the very durable rock at the top of the Grand Canyon stack), but there's certainly some kind of difference. It might be a carbonate thing; both the underlying Platteville and overlying Cummingsville/Prosser, which have more limestone and dolomite, also have more diverse mollusks than the muddy Decorah (Sloan and Webers 1987). On the other hand, the relatively limited diversity and abundance of snails, combined with most genera having visually distinctive appearances, make it possible to summarize them in a reasonably brief guide.

*and things that look a whole lot like snails, and things that people argue about, such as Sinuites

Several snails in a small section of a slab: C for Clathrospira, S for Sinuites, and L for "lophospiroid".