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.

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.