Feathered Crocs?!

Hot on the heels of the recently discovered feathered ornithiscian Tienyulong confucusi from China is another amazing discovery, one that shakes up our idea of archosaurs as we know them. For years now, the Fergana region of Kyrgyzstan has been known to produce amazingly preserved fossils, mostly insects and invertebrates, but occasionally strange and unusual vertebrates, such as the enigmatic Sharovipteryx and Longisquama.

Well, today, another strange critter made that list. Meet Agriosuchoides inexpectatus, a crurotarsian archosaur from the Late Triassic (Ladinian/Carnian time) of Kyrgystan. This find is important enough by itself, the anatomy of Agriosuchoides appears to suggest that it is the most primitive crocodylomorph ever found, possible related to the sphenosuchians or other primitive, gracile crocodiles. But that is not even the most exciting part. The most exciting part of all is that the fossil appears to be preserved with what appear to be protofeathers around the shoulders, neck, and head!

This has amazing implications. If Agriosuchoides is real, this would mean that feathers or protofeathers are not just found in ornithodirans, as the current fossils of pterosaurs, Tienyulong, Psittacosaurus, and theropods suggest, but that they were present on all archosaurs. The modern day crurotarsians, the semi-aquatic crocodiles, probably lost their feathers secondarily to retain heat better in water, just like whales have today.

Once we get past the feathers, Agriosuchoides appears to be a normal, if somewhat primitive crurotarsian. Some have suggested that Agriosuchoides is not actually a crocodylomorph, but instead a much more primitive crurotarsian archosaur, one that evolved a sphenosuchian-like body shape through convergent evolution. But none doubt that it is a crurotarsian; the distinctive crurotarsian ankle makes that point very clear.

So what does this mean for paleontology? Well, for one it could suggest that all of those Triassic archosaurs we see could be fluffy. Rauisuchians, aetosaurs, probably not phytosaurs, but they all could be fuzzy to an extent. It also raised the question "how basal are feathers". The feathers of Agriosuchoides are more primitive than those found in pterosaurs and dinosaurs; slightly more scale-like than "dino-fuzz", but it still doesn't answer our question as to how early did feathers evolve. More fossils will be needed for the answer.