Half Bird, Half Croc: Silescelida acristata

Publication Info:

Transcript:

M.S. Garcia et al. 2026. A new eucrocopodan archosauriform from the Middle Triassic of southern Brazil and the phylogeny of Euparkeriidae. Sci Rep 16, 16585; doi: 10.1038/s41598-026-53740-9

Meet Silescelida acristata, the newly named Euparkeriid archosauriform from Brazil. This species isn't a direct ancestor of either dinosaurs or crocs, but a fairly close relative of both groups!

Episode 302

Notes:

So if you ever seen an animal that's halfway between a croc and a bird, here's your most recent paleontology news almost daily or whenever I get around to it. So first things first, even though crocs and gators get called dinosaurs a lot, they aren't. They absolutely 100% are not dinosaurs, but birds are and they're all archosaurs. The croc line archosaurs or pseudosuchia broke off from the bird line or dinosaur line archosaurs which is avemetatarsalia which also includes pterosaurs something like 250 million years ago. Yeah, there was a recent paper pushing it back a little bit more, but we'll just say 250 million years as ballpark. True archosaurs along with some other groups make up archosauriforms and archosauriforms is the group that somehow managed to survive the end Permian mass extinction. Very quickly after diversifying and taking over the planet and never really loosening their grip on it. It does mean that somewhere back in the early Triassic there is a common ancestor between birds and crocs and it could have looked something like this new species. Meet Silescelida acristata, the newly named euparkeriid archosauriform from Brazil. Euparkeriidae is a complicated and somewhat controversial group or at least the exact members of it are, but with this discovery there are now confirmed at least two members. Silescelida and the group's namesake Euparkeria from South Africa with a handful of other members that some consider valid, some don't. I'm not getting into it. But they were small, lightly built archosauriforms with a body that looked something like a mix between a lizard and a bird and they could even run upright wanted to. And a very pseudosuchian head. They're outside of both avemetatarsalia and pseudosuchia and most likely not a direct ancestor of either group, but they do really look like a mix of the two. As usual, if you want more information, here's the source.