The Camptosaurus Challenge

Camptosaurus dispar skeletal by Scott Hartman

If any of you dear readers follow me on Twitter (@zmiller1902) or any of my blogger colleagues (there’s a handy list at the bottom of this post) you’ve probably seen at least a few entries in the hashtag Camptosaurus challenge. For the deets, check out David Orr’s two posts on this very topic and the deluge of paleoart that it inspired. You’ll see that I have two rather terrible entries—both were rush jobs—but I was determined to put something respectable together last night and I’m pretty happy with the result:

Lesser-Known Running Lizards (minor update at the end)

by Jaime Headden, from Wikipedia

In the last post, I briefly mentioned a group of dromaeosaurs called unenlagiines. This is still a rather obscure group, especially to the general public, so I wanted to give these South American dromaeosaurs some much-deserved time in the spotlight.

This is a small group—only three (but possibly four or five) genera have been named. They are atypical dromaeosaurs for a number of reasons, foremost among them the elongate, narrow snout packed with minute teeth which lack serrations. While most appear to have been small, one of them was one of the largest dromaeosaurs, approaching Achillobater and Utahraptor in terms of overall size.

Nearly Birds

Adorable Serikornis sungei by Emily Willoughby

Something I really enjoy about paleontology is how quickly things can change. For example, when I was growing up, Dromaeosauridae was confined to half a dozen genera from two continents. If you wanted a complete list, you could check out Raptors: The Nastiest Dinosaurs from your local library. Now, though, Dromaeosauridae is more like Dromaeosauriformes because there are something like five distinct groups now: Halszkaraptorinae, Unenlaginae, Microraptorinae, Dromaeosaurinae and Velociraptorinae (those last two are usually stuck together in a monophyletic Eudromaeosauria). It used to be that dromaeosaurs came in two flavors: large and small. Now you’ve got swan-necked, duck-billed dromaeosaurs; piscivorous, leggy dromaeosaurs; tiny, potentially volant dromaeosaurs; and larger “classic” predatory dromaeosaurs.

All this has happened in the last twenty years. Heck, nobody knew about Halszkaraptor until a few weeks ago.

Chilesaurus and Avian Arm Folding

Chilesaurus diegosuarezi by the impeccable Jaime Headden

Ever since the publication of supreme oddball Chilesaurus (eat your heart out, Halszkaraptor), I’ve been dying for somebody out there to do a full description of the critter’s unusual skeleton. As Chilesaurus may hold the key to our understanding of early ornithischians (or not), this is an animal in dire need of detailed study. This past Sunday, a paper was published in a journal that I can’t pronounce—Ameghiniana—and it is not that description. However, it is very interesting, and since I imagine many of you don’t have access to, uh, Ameg-HEE-ana (?), I thought I might summarize the juicy parts here.

An Aelurodon of My Own

Aelurodon ferox chasing Neohipparion, by Mauricio Anton

You know, I never blogged about my SVP 2017 experience, more out of sloth than anything else. I can wrap up my thoughts with this sentence: it was fun but very lonely. For me, perhaps the most enjoyable part of the conference was the silent auction. I should have stayed for the following “real” auction because photos posted to social media afterward made it look insane, but I had a bunch of meds to do and an early start the next morning. I bid on several items in the silent auction, most of them 3D prints of interesting fossils, but I was quickly outbid past my own point of comfort for most of them. However, I was able to secure this nifty specimen:

Peg Teeth

I’m in the midst of drafting (for the third time) an upcoming post about Drepanosaurus and Avicranium but I doubt they’ll be done by the end of the month. However, I wanted to get something up on this darn blog because I'd like to maintain the illusion of being loyal to my seven or eight readers. So I’m going to briefly discuss something strange about ceratopsians that nobody ever seems to comment on: the weird peg teeth of basal neoceratopsians.

Very Specific Strange Reptiles

Azendohsaurus madagaskarensis by Matt Celeskey.

The term "strange reptiles" could apply to just about every animal I've ever written about on this blog, so you'll forgive me for not loving the name Allokotosauria, an up-and-coming group that was formalized in 2015. The name really says nothing about its members, the similarly newly-minted Azendohsauridae and the longstanding Trilophosauridae. These are archosauromorphs that sit well outside of the Ornithodira-Crurotarsi divide, and are instead related to such eclectic animals as rhynchosaurs and protorosaurs. As I suspect my readers have at least heard of Trilophosaurus, I'll start this essay by discussing Azendohsaurus.

And Then There Were None

Today, we add an addendum to what’s turned out to be one of my favorite blog posts: Hopeful Dinosaurs. In that essay, I introduced you all to a group of near-dinosaur dinosauriforms called silesaurids. These small, quadrupedal, herbivorous critters all hail from the Late Triassic, but were impressively cosmopolitan, being found in the United States, South America, Africa, and Poland.

The Saurosphargid That Wasn't

Saurosphargid by Ethan Kocak

You might all remember that, some time ago, I introduced you all to an obscure group of Triassic marine reptiles called saurosphargids. This strange group of tubby critters includes just three genera: Saurosphargis, Largocephalosaurus, and Sinosaurosphargis. Confusingly, Nosotti & Reippel (2003) named and described Eusaurosphargis under the assumption that the original genus—Saurosphargis—was a nomen dubium as the original (and only) specimen of that taxon was destroyed during WWII.* Nosotti & Reippel named it Eusaurosphargis even though—according to their own analysis—Eusaurosphargis was not a saurosphargid, but a sister taxon to Hovasaurus, a very different marine reptile from the Permian. They could not decide whether Eusaurosphargis was aquatic or terrestrial, but since it was routinely found to be closely allied to Triassic marine reptiles, though, a life aquatic was the more obvious choice.

The Long, Complicated History of Appalachian Ceratopsians

North America during the Campanian

The title is a joke. Finding ceratopsian remains east of Texas is an incredibly recent phenomenon. Oh sure, there are plenty of (fragmentary) dinosaurs known from the eastern half of the United States, but those taxa tend to be tyrannosauroids, nodosaurs, ornithomimids, and hadrosaurs. I should mention at this point that, during much of the Late Cretaceous, North America was cleaved into three islands by the presence of a shallow interior sea called the Western Interior Seaway (WIS): Laramidia to the west, Nunavut to the north, and Appalachia to the east. Laramidia’s eastern north-south shoreline is where we get most of North America’s dinosaurs—Alberta, Montana, Utah, and (to a lesser extent) Texas are all hotbeds of dinosaur action, and that includes ceratopsians.