Platyhystrix

Platyhystrix (from Greek: πλατύς platús, 'flat' and Greek: ῠ̔́στρῐξ hústrix, 'porcupine') is an extinct temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, Dimetrodon and Edaphosaurus. It lived during the boundary between the latest Carboniferous and earliest Permian periods throughout what is now known as the Four Corners, Texas, and Kansas about 300 million years ago.

Not much is known about Platyhystrix, with a majority of the fossils found composed of the distinct neural spines, and fractured skull fragments. There is only one species within the genus. Its phylogenetic relationship to other members of the family Dissorphoidae has been debated in recent years, due to its unique cranial features, and recent discoveries as to the origins of modern day Lissamphibians. Synonyms and alternate spellings include: Zatrachys apicalis, Ctenosaurus rugosus, Platyhystryx, Platyhistryx.