''Platyhystrix'' (from el, πλατύς , 'flat' and el, ῠ̔́στρῐξ , 'porcupine') was a

temnospondyl Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carb ...

amphibian with a distinctive sail along its back, similar to the unrelated

synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes rep ...

s, ''

Dimetrodon ''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non- mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodo ...

'' and ''

Edaphosaurus ''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous t ...

''. It lived during the boundary between the latest Carboniferous and earliest Permian periods in

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, about 300 million years ago.

Palaeobiology

''Platyhystrix'' may have been preyed upon by larger temnospondyls such as '' Eryops'', or by larger carnivorous reptiles, which were becoming more common and diverse in the drier climate of the Permian. The skull was large and strongly built, with a frog-like face. ''Platyhystrix'' had a compact body, reaching long including the tail, and its short, sturdy legs indicate a mainly terrestrial life. ''Platyhystrix'' appeared rather unusual: the dorsal vertebrae were extraordinarily lengthened, and in life they probably formed a skin-covered sail. This structure was possibly for thermal regulation, as in other animals of similar appearance, such as the pelycosaurs ''

'' and ''

''. The back of ''Platyhystrix'' was also covered with thick hard plates, similar to those of its near relative, ''

Cacops ''Cacops'' ("ugly look" for its strange appearance), is a genus of dissorophid temnospondyls from the Kungurian stage of the early Permian of the United States. ''Cacops'' is one of the few olsoniforms (dissorophids and the larger trematopids ...

''.

References

* Vertebrate Palaeontology by Michael J. Benton and John Sibbick * The Simon & Schuster Encyclopedia of Dinosaurs and Prehistoric Creatures: A Visual Who's Who of Prehistoric Life by Barry Cox, Colin Harrison, R.J.G. Savage, and Brian Gardiner * Bibliography Of Fossil Vertebrates 1934-1938 by C. I. Camp Dissorophids Carboniferous temnospondyls of North America Cisuralian temnospondyls of North America Permian geology of Texas Prehistoric amphibian genera {{temnospondyli-stub