What is "psephoderma"

Psephoderma (meaning "pebbly skin", from the Ancient Greek psepho (ψῆφος), "pebbly", and derma (δέρμα), "skin" is a genus of placodont that was very similar to its relatives Placochelys and Cyamodus. Psephoderma had a flattened skull and a narrow, straight rostrum. Inside this skull, embedded in the jaws, were rounded teeth specialized for crushing the shellfish it ate. Unlike most placodonts, Psephoderma had a carapace that was divided into two pieces, one on the shoulders and back, another on the rear end. Psephoderma grew to 180 cm long and lived in the Late Triassic ( Norian), about 210 million years ago. It was one of the last placodonts to live.