Placerias was a dicynodont (a group of mammal-like reptiles) that lived during the late Carnian age of the Triassic period. It was a member of the family Kannemeyeridae, the last known representative of the group in North America. It was the largest herbivore of its environment, measuring up to 3.5 metres long, and weighing one or two tonnes. It used a beak with two short tusks to uproot plants; the tusks may also have been for intra-specific display.

Fossils of forty placeria were found at the Petrified Forest in Arizona.