Oldest Fossilized Butthole Found in 290-Million-Year-Old Reptile

alternative_right writes: The fossil hails from the sedimentary Goldlauter Formation in Germany's Thuringian Forest Basin, and an analysis of the impression left behind shows it was made by a reptile about 9 centimeters (3.5 inches) in length.

In the mud, it left a clear impression of what appears to be belly scales, structures made of hard keratin that act as armor. But the real showstopper is at the base of the tail, where modified scales surround a vent-like opening – what appears to be a cloaca.

It smashes the previous record, a Psittacosaurus butthole dated to around 120 million years ago, and now represents "the earliest fossil record of a cloacal vent in amniotes", the researchers write in their paper, supporting long-held views that the cloaca was present in early reptiles.