6.4" Permian Amphibian (Trimerorhachis) Leg - Oklahoma

This is a fossil leg/hand of the primitive, Permian amphibian Trimerorhachis. The fossil Trimerorhachis bones were all collected from a single layer in the Ryan Formation of Oklahoma and painstakingly composited together.

Trimerorhachis was an early dvinosaurian temnospondyl which could reach about 1 meter in length. It had a distinctive triangularly shaped head full of sharp, pointy teeth and stubby legs. It was likely an aquatic predator, preying on fish and small vertebrates.



During the Early Permian, the area of New Mexico and Texas was a broad coastal plain that stretched from an ocean in the south to highlands in the north. Other common animals that lived alongside Trimerorhachis included lungfish and crossopterygians, the lepospondyl Diplocaulus, and the large sail-backed synapsid Dimetrodon.