Trimerorhachus insignis tooth from the Lower Permian, collected in Jefferson County, Oklahoma. Trimerorhachus insignis is an ancient amphibian. This is an aquatically adapted Tempnospondyli i.e. a type of extinct small to giant tetrapod which inhabited lakes, rivers and other fluvial subenvironments. It used its sharp teeth to prey upon small fish and other small amphibians. These fine tooth specimens are very rare, they measure approximately 1 cm long and 0.5 cm wide and are supplied in a small plastic bag with an information label.