Thursday, January 14, 2021

Hopeful Pterosaur(omorph)s

Lagerpetid by Rodolfo Nogueira

As we’ve seen, the Triassic was a period filled with all manner of charismatic animals, including reptilian platypuses and whales, praying mantis-like drepanosaurs, semi-aquatic dragons, pseudosuchian dinosaur mimics, and everything in between. We have not, however, in our Triassic adventures, yet directly touched on the typical touchstones of Mesozoic diversity: pterosaurs and dinosaurs. In part, that has been intentional: why focus on dinosaurs when there are so many other wonderful animals to learn about during the Triassic? But another, perhaps more interesting, reason is that dinosaurs and pterosaurs simply weren’t a particularly large or diverse component of Triassic ecosystems until the very end. I would argue that the dinosaur's reign didn’t really begin until the Triassic-Jurassic extinction event removed their pseudosuchian competitors. Pterosaurs, too, diversified during the Jurassic, although I'm not sure if anything was keeping them down before. Anyway, until the Jurassic, these would-be prehistoric paragons were living in the shadows of predatory rauisuchians, herbivorous aetosaurs, giant dicynodonts, and semi-aquatic phytosaurs. No revolution, however, comes from nothing. Dinosaurs and pterosaurs had ancestors too, and in this essay, we’ll focus on one their most distant relatives, the lagerpetids.

Thursday, September 24, 2020

Slightly More Hopeful Dinosaurs

Lewisuchus--basalmost ornithischian? (from Ezcurra et al., 2019)

Dear me, it’s been awhile, hasn’t it? My tardiness in keeping this blog going has not been entirely intentional; 2020’s been a year for the records? I only hope it ends on December 31st and doesn’t continue on in some space-time warping extension into December 32nd. Nonetheless, I am motivated today to inform you all about a paper that brings together several topics I’ve written about in years past: silesaurids, Pisanosaurus, and the Triassic Ornithischian Crisis. Below, I will offer the briefest of recaps, but hit those links if you want a more complete picture.

Thursday, February 6, 2020

Marine Snouters of the Triassic II: Gunakadeit Rising

Alaska's own Gunakadeit joseeae by the amazing Gabriel Ugueto, or @SerpenIllus on the Twitters.

A very long time ago, I posted an essay about one of my favorite groups of Triassic marine reptiles: thalattosaurs. These lizard-shaped swimmers, while generally similar in body form, differ from one another quite strongly in terms of feeding adaptations. While Anshunsaurus and Askeptosaurus may seem, to our modern eyes, rather vanilla in their clearly faunivorous dentition, others strain credulity. Xinpusaurus, for example, possesses a bizarre notched upper jaw and, in some specimens, an elongate premaxillary spear which overshoots the the lower jaw by an impressive degree, calling to mind swordfish and swordfish-snouted ichthyosaurs. Thalattosaurus and its “claraziid” brethren have reduced, shell-crushing dentition and snouts which curve downward—Hescheleria takes this trend to a puzzling extreme. Thalattosaurs also occupied a wide range of body lengths (1-5 meters). While some were more terrestrially capable than others, the group never seemed to stray far from the nearshore niche.

Thursday, May 30, 2019

Walk This Way

The right manus of Camarasaurus. Note the columnar arrangement and virtual absence of fingers.
Late last year, I introduced you all to the Lessemsauridae, a group of near-sauropod "prosauropods" that grew unreasonably large—up to 12 tons in Ledumahadi mafube. There’s some disagreement about the posture of these enormous animals: in true, blue Sauropoda, the forelimbs are columnar, the hands are pronated, the weight is bore on the fingertips, and there is a reduction in phalanges and claws. This arrangement is present to some degree even in the earliest true sauropods like Melanorosaurus and Barapasaurus.

Thursday, May 2, 2019

Don't knock my Smok or I'll clean your clock!

We miss you, Bill Watterson.
A few months ago, I wrote that my favorite paleo story of 2018 was the publication of Lisowicia bojani, a ridiculously large dicynodont from Poland. In that same post, I mentioned Smok wawelski, a similarly-sized predatory archosaur of uncertain phylogenetic affinities that very likely hunted Lisowicia. It strikes me that Smok might be unfamiliar to many of you out there in Readerland, so today’s quick post is a summary of what we know about this mysterious carnivore. By the way, I posted this Calvin & Hobbes strip because every time I hear the name Smok I immediately think of it.

Friday, January 25, 2019

Whale-Lizards of the Triassic III: Revenge of Eretmorhipis

You might fondly remember the two previous posts in this series: Part I and Part II which describe a particularly bizarre group of basal ichthyosauromorphs called hupehsuchians. Known for their "bony body tubes" and wide, toothless mouths, hupehsuchians are a surprisingly diverse group that includes five monospecific genera: Nanchangosaurus, Hupehsuchus, EohupehsuchusParahupehsuchus, and EretmorhipisEretmorhipis is the most recently-described hupehsuchian (Chen et al. 2015) but also one of the more mysterious, as the holotype does not include a skull or even cervicals. I should mention this is also the case with Parahupehsuchus although it's missing most of the tail, too.

Tuesday, January 8, 2019

Big Finish to 2018

Despite Sergey Krasovskiy's gorgeous art, it is not Crittendenceratops.
First of all, sorry for not writing anything in December. We spent half the month on vacation and the other half madly trying to finish things before the vacation and playing catch-up after the vacation. It was a good vacation; we went to Kauai. I don’t know if you’ve ever been to Kauai but it’s the complete opposite of Alaska, especially during December. I did some writing while on vacation but nothing serious and besides I didn’t have any of my reference material on-hand. However, I did work on a longer-term project that's been on my mind for awhile now. Details as they emerge.

Friday, November 16, 2018

Thanos Deserves Better

Thanos, the Mad Titan, disappointed with his namesake.
A new dinosaur was published today in Historical Biology: Thanos simonattoi, named after Sergio Simonatto, who discovered the specimen, but more visibly Thanos, the Marvel villain. It might not shock you to known that Rafael Delcourt's name is on this paper. A few months ago, he gave us the Etrigansauria, an unnecessary name that has designs on replacing the perfectly-good Neoceratosauria. Delcourt & Vidoi lori (2018) identify Thanos as an abelisaurid close to Brachyrostra. This all seems fine until you see the holotype:

Tuesday, October 23, 2018

They Might Be Giants

Ingentia prima by Jorge Gonzalez
Two recent news stories perked my interest recently—the descriptions of two new non-sauropod sauropodomorphs: Ingentia prima from the Late Triassic of Argentina and Ledumahadi mafube from the Early Jurassic of South Africa. Together, these animals (and two others which I’ll get to) form a clade of non-sauropod sauropodomorphs that achieved gigantism independently from true, blue sauropods, which is intriguing for a number of reasons.

Friday, September 7, 2018

An Update on Stem Turtles

The beaky noggin of Eorhynchochelys by...IVPP?

Couple things I need to talk about. First, it's been a very long time since I've blogged, which was not my intention (it never is). I hit a rough patch of writer's block, which was followed up by a 9-day stint at the hospital where I got a CF-related tune-up. Taxonomy Tuesday is not proving to be the rich well of inspiration I was hoping for, so while I still intend to write up Taxonomy Tuesdays, they almost certainly won't be weekly. Now then, right before I was admitted, I wrote this short post about a new stem turtle. I wrote about turtle origins way back in 2015 and I'm always excited when a new one pops up. Thankfully, in addition to this post, I'm halfway through essays about mesosaurs and tanystropheids, so regular blogging will commence soon.