Placerias

Placerias was a sturdy animal with tusks for rooting through the soil in search of a range of vegetation and a beak for uprooting plants. Fossil evidence from tusks from other dicynodonts show wear patterns of alternate deep grooves and a smoother polishing effect. Some palaeontologists have interpreted this as evidence that they lived in a highly seasonal environment. In the dry season the earth they dug up would be hard and granular, causing deep grooves on their tusks. In the wet season, the ground would be wet and silty, helping to polish them.
The best fossil find was at the Petrified Forest at St Johns in Arizona where forty individuals were identified. A low-slung, powerful animal resembling a hippopotamus, Placerias was not a dinosaur, but a dicynodont or "two-dog tooth", so called because it had toothless jaw margins with only the two canine teeth, near the front. Dicynodonts are therapsids, or mammal-like reptiles, a group that includes the ancestors of modern mammals.
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Category:Triassic Animals
Category:Extinct Animals
Category:Arizona Animals