Saturday, February 20, 2021

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.

Saturday, February 13, 2021

Your Friends The Titanosaurs, part 33.2: Alamosaurus of Utah and points north?

We head north into Utah this time for the next major discoveries of Alamosaurus. Unlike Alamosaurus of the San Juan Basin or the Big Bend area of Texas (as we'll see next time), Alamosaurus sanjuanensis from the North Horn Formation of Utah has been more or less represented by one specimen, although others are known. Fortunately, that one specimen has been very informative in its own right. In addition to Utah, we have sketchy references to finds in Wyoming and Montana to deal with, plus a couple of incomplete threads from the San Juan Basin to tie up.

Saturday, February 6, 2021

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.)