Benggwigwishingasuchus: The Fisher Crocodile
I once again come bearing news from the realm of Pseudosuchia. Yes, we got a new taxon. Benggwigwishingasuchus eremicarminis ("Fisherman Croc's desert song") is a new basal member of the poposauroidea, a clade you might have heard about before.
But first some more key notes. Benggwigwishingasuchus has been recovered from the Anisian Fossil Hill Member of the Favret Formation, located in the US State of Nevada. It is known from a decently complete skeleton that preserves much of the neck and torso, a decent chunk of the limbs but only small pieces of the skull.
Left: Press release artwork of Benggwigwishingasuchus looking across the Panthalassan Ocean (Jorge A. Gonzalez) Right: Fossil material
As said already, Benggwigwishingasuchus is considered a member of the poposauroidea, one of the most enigmatic groups of early pseudosuchians. The reason for that is that we primarily know them from their most derived members, the bipedal Poposaurus, the sail-backed ctenosauriscids, Lotosaurus, the ornithomimosaur-mimics of the Shuvosauridae and Qianosuchus. As you can see many appear kind of like proto-dinosaurs and most have lost their osteoderm armor, requiring a whole different skeletal structure to support their erect posture. But until recent years we knew little and less about where they came from. This is thankfully starting to change now, since we now not only have Benggwigwishingasuchus, but also Schultzsuchus (formerly "Prestosuchus" loricatus) described earlier this year, Mambawakale from two years ago and recently assigned to the group as well as Mandasuchus (similar to Mambawakale originally described as something else and recently considered as a basal poposauroid). Thanks to these we are slowly starting to see a transition. Schultzsuchus still has pretty standard armour for example, but Qianosuchus shows clear signs of reduction, with Benggwigwishingasuchus kinda falling into the middle between them.
Assorted Poposauroids: clockwise from top right: Poposaurus (Skye McDavid), Arizonasaurus (Gabriel Ugueto), Lotosaurus (Gabriel Ugueto), Shuvosaurus (Joschua Knüppe)
What's also interesting about Benggwigwishingasuchus is its ecology, or what little we can infer based on the circumstances of its preseration. You see, the Favret Formation preserves marine sediments and was previously best known for its ichthyosaurs (including the giant Cymbospondylus). So its kind of weird seeing a rather lanky pseudosuchian there. What's weirder still is the fact that the preservation seems to suggest that it wasn't swept out. No, its still reasonably complete, partially articulated and in the classic death pose with its back bent backwards, this thing was moved little before being burried. BUT. It wasn't marine. The skeleton fits of a terrestrial animal and both limb proportions and histology show no evidence of it being a swimmer or diver. Instead its hypothesized that it might have been an animal that inhabited the coast, possibly drawing sustenance from the sea but not actively adapted to forage in it. In this sense Benggwigwishingasuchus could parallel Ticinosuchus from Switzerland and Qianosuchus from China, both of which were coastal animals yet not explicitly aquatic (in the case of Qianosuchus it was originally proposed given its specialised tail, but recent work seems to suggest it was never very fast nor enduring).
Top image: Benggwigwishingasuchus standing on the skull of Cymbospondylus (Joschua Knüppe) Bottom left: Ticinosuchus among a group of Tanystropheus (Zach Robinson) Bottom right: Qianosuchus holding a fish (Gabriel Ugueto)
All in all, Benggwigwishingasuchus is an interesting animal that does fill in some gaps in the fossil record, both phylogentically and ecologically and though the description is sparce on actually describing the skeleton, here's hoping that more research will come out eventually. Hell, they dropped a histology on it like a day after it was named.
Wikipedia:
Benggwigwishingasuchus - Wikipedia Papers: A new pseudosuchian from the Favret Formation of Nevada reveals that archosauriforms occupied coastal regions globally during the Middle Triassic | Biology Letters (royalsocietypublishing.org)
Diverse growth rates in Triassic archosaurs—insights from a small terrestrial Middle Triassic pseudosuchian | The Science of Nature (springer.com)
