Compact Thescelosaurus Year Nine

October and National Fossil Day have rolled around again (check out the fall 2024 Park Paleontology News, too!), so it's time to take a look at the previous year's changes to The Compact Thescelosaurus and welcome some new content. First, the new stuff: I'm sure you'll be shocked to find out I've followed up Triassic pseudosuchians with... Jurassic pseudosuchians. I'm rearranging the pseudosuchian content a bit, to have the non-crocodylomorphs on one sheet and the crocodylomorphs on another. This was done to forestall the deployment of an unwieldy number of "subdivision" columns. Provided I get far enough along, something similar might have to happen with the new sheet around Crocodylia or so. Anyway, the main takeaways I got out of Jurassic pseudosuchians are 1) there's been a lot of work on thalattosuchians over the past couple of decades, and 2) I've discovered I'm not very fond of thalattosuchians and certainly don't mind that they conk out midway through the Cretaceous.

Hey, it's the Science Museum "Goniopholis" again! (Most Jurassic pseudosuchians are thalattosuchians, but North America is largely bereft of the darlings, so we make do with crocs like these.)

Compact Thescelosaurus Year Eight

It's that time again, for National Fossil Day (October 11 this year), a new sheet for The Compact Thescelosaurus, 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 Park Paleontology News is up for viewing. Also in breaking NPS paleontology news: additional dating of the fossil human tracks at White Sands National Park, and a previously overlooked record of a tyrannosaur tooth at Yellowstone National Park. [Update, 2023/10/10: And a tritylodont bonebed at Glen Canyon National Recreation Area was just announced; goes well with this new paper on a massive track block from the recreation area, too.]

Here at Equatorial Minnesota, we've passed 400 entries this year. Later this year, December 15 will mark 10 years of posting. (Also, anyone know why this nautiloid post 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.

Prestosuchus threatening an Eoraptor in the "Ultimate Dinosaurs" exhibition at the Science Museum of Minnesota, May 2014.

Compact Thescelosaurus Year Seven

Here we are at the second weekend of October, which means it's time for three things: National Fossil Day; a new sheet for The Compact Thescelosaurus; and our annual roundup of what's been added to the spreadsheet. National Fossil Day falls on Wednesday, October 12 this year, although events occur throughout the month (especially the weekends before and after), so check your nearest museum or National Park System unit for events! Our fall Park Paleontology newsletter is also up for viewing (including more fun with packrats).

Compact Thescelosaurus Year Six

The time has come again for the annual review of The Compact Thescelosaurus. This year's new page is on aetosaurs and their close relatives, with the classification diagram page updated. (Don't forget, Wednesday the 13th is also National Fossil Day!)

Aetosaur Desmatosuchus spurensis is one of the subjects of the NPS Prehistoric Life Coloring Book. Coincidentally, an aetosaur also featured in the 2014 National Fossil Day artwork.

Compact Thescelosaurus Year Five

It's time for the annual review of The Compact Thescelosaurus. As is traditional, there's a new sheet, which this year covers mosasaurs, as you might have guessed from the image. The classification diagram page has been updated as well. (Don't forget, Wednesday the 14th is also National Fossil Day!)

Mosasaurus conodon, hanging out at the Science Museum.

Compact Thescelosaurus Year Four

It's time for the annual update to The Compact Thescelosaurus, now entering its fifth year. This time, ichthyosaurs join the group, which is really stretching it for me, but hopefully it's not entirely in vain. Ichthyosaurs fared a bit better than plesiosaurs in that *only* 91 of the 224 species (40.6%) included are of questionable validity, rather than 173 of 318 (54.4%). (Only.) My go-to work was McGowan and Motani 2003 on Ichthyopterygia (Handbook of Paleoherpetology 8), just to figure out what was there. Ichthyosaurus itself, like Plesiosaurus, accumulated an awe-inspiring retinue of species over the years, but it's not alone. A couple of areas of ichthyosaur taxonomy are pretty volatile at the moment as massively specious genera are re-evaluated, so expect revision. (Also expect the usual formatting bugs and obvious corrections that come with a new sheet.)

Sure, like you don't know what an ichthyosaur looks like. This was found at Wikimedia Commons, but originally came from a short item by William Diller Matthew in the American Museum Journal for January 1908.

New Pages: Geologic Time Scale and Classification Diagrams

So far the year has been quiet (well, up until Friday), so I thought I'd address a couple of nagging things, which I've done by adding two pages. The first page is a geologic time scale figure, from one I worked up for National Park Service reports. It's the kind of thing I thought would be handy to have on hand here for reference, instead of having a link to an external site. It'll be updated from time to time as dates are refined. The Quaternary is rather cramped, although I don't feel particularly apologetic for shortchanging Homo sapiens.

The second page is a sort of "map" to the classifications used in the various sheets over at The Compact Thescelosaurus, made with classic ASCII cladograms. (I contemplated drafting them in other ways, but none of them were as amenable to updating.) I thought this would be useful for visualizing the mess of classification columns. The process also forced me to look at the positions of a few clades, as you may have noticed from the updates sheet.

It's not connected to either topic, but I've also added a paragraph of new information to the post on the "Kweichow sauropod" after coming across a mention of it in Averianov and Sues (2017).

Finally, so as not to leave the post without an image, here's one attached to a quick story:

Back in spring 2001 I was on a field trip to the Badlands/Black Hills area of southwestern South Dakota. We were stopped along a road near Deadwood for lunch. One of the professors said something to the effect that "there are fossils in this formation." I looked down at the chunks of rock at my feet and said "You mean like this?"

Yeah, like this.

From my notes the source is the Whitewood Formation (or Dolomite, or Limestone), fittingly enough an (surprise, surprise) Upper Ordovician unit. More on its cephalopods can be found in Miller and Furnish (1937).

References

Averianov, A., and H.-D. Sues. 2017. Review of Cretaceous sauropod dinosaurs from central Asia. Cretaceous Research 69:184–197. doi:10.1016/j.cretres.2016.09.006.

Miller, A. K., and W. M. Furnish. 1937. Ordovician cephalopods from the Black Hills, South Dakota. Journal of Paleontology 11(7):535–551.

Compact Thescelosaurus Year Three

It's mid-October, with National Fossil Day coming up (Wednesday the 17th) and the anniversary of the original Thescelosaurus just behind us (Sunday the 7th). It's also time for something new for The Compact Thescelosaurus on its third birthday. Last year, pterosaurs joined dinosaurs and choristoderes. This year, plesiosaurs and a variety of more basal sauropterygians and possible sauropterygians join them.

Elasmosaurid Thalassomedon haningtoni, Denver Museum of Nature and Science