Platyhystrix
| Platyhystrix | |
|---|---|
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Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Tetrapoda |
| Order: | †Temnospondyli |
| Family: | †Dissorophidae |
| Genus: | †Platyhystrix Williston, 1911 |
| Species: | †P. rugosus
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| Binomial name | |
| †Platyhystrix rugosus (Case, 1910)
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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.[1][2][3] There is only one species within the genus. It’s 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.[4][5] Synonyms and alternate spellings include: Zatrachys apicalis, Ctenosaurus rugosus, Platyhystryx, Platyhistryx[6][7][8][1].
Discovery/ Historical Information
The holotype for Platyhystrix (AMNH FARB 4785) was first discovered in the Early Permian Cutler formation in Rio Arribas Co, New Mexico in 1881 by American paleontologist, E.D. Cope.[9] The holotype consisted of a few fragmented neural spines, and was initially listed under the species name, Zatrachys apicalis.[9] In 1910, American paleontologist E.C. Case reclassified the neural spines as belonging to a new species of the Pelycosaurian reptile, Ctenosaurus rugosus (rugosus meaning wrinkled, shriveled), since they resembled spines from Texas, belonging to Ctenosaurus koeneni described by Friedrich von Huene.[9]
In Case’s description of the Platyhystrix holotype, he initially classified it as part of a new reptile specimen, but still noted tubercles along the neural spines which were similar to the projections found on amphibian skulls.[9] It was S.W. Williston who created the genus, Platyhystrix, in 1911, and placed it within the Temnospondyli order once fractured skull elements were described in 1916.[8][6]
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 1 metre (3.3 ft) long including the tail, and its short, sturdy legs indicate a mainly terrestrial life.[10]
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 Dimetrodon and Edaphosaurus. The back of Platyhystrix was also covered with thick hard plates, similar to those of its near relative, Cacops.[10]
Phylogeny
Cladogram produced by Schoch (2012):[5]
| Dissorophoidea |
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References
- ^ a b Case, E.C. (1910). "New or little known reptiles and amphibians from the Permian (?) of Texas". Bulletin of the American Museum of Natural History. 28: 163–181.
- ^ Berman, David S.; Reisz, Robert R.; Fracasso, Michael A. (1981-12-18). "Skull of the Lower Permian dissorophid amphibian Platyhysthx mgosiis". Annals of the Carnegie Museum. 50: 391–416. doi:10.5962/p.214500. ISSN 0097-4463.
- ^ Vaughn, Peter Paul (1962). "Vertebrates from the Halgaito Tongue of the Cutler Formation, Permian of San Juan County, Utah". Journal of Paleontology. 36 (3): 529–539. ISSN 0022-3360.
- ^ Atkins, Jade B.; Reisz, Robert R.; Maddin, Hillary C. (2019-03-22). "Braincase simplification and the origin of lissamphibians". PLOS ONE. 14 (3): e0213694. doi:10.1371/journal.pone.0213694. ISSN 1932-6203.
{{cite journal}}: CS1 maint: article number as page number (link) CS1 maint: unflagged free DOI (link) - ^ a b Schoch, Rainer R. (August 2012). "Character distribution and phylogeny of the dissorophid temnospondyls". Fossil Record. 15 (2): 121–137. doi:10.1002/mmng.201200010.
- ^ a b Williston, Samuel Wendell (1911). American Permian vertebrates,. Chicago, Ill.,: The University of Chicago Press.
{{cite book}}: CS1 maint: extra punctuation (link) - ^ "I. The structure, evolution and origin of the amphibia. - The "orders' rachitomi and stereospondyli". Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character. 209 (360–371): 1–73. January 1920. doi:10.1098/rstb.1920.0001. ISSN 0264-3960.
- ^ a b Williston, S.W. (1916). "Synopsis of the American Permo-Carboniferous Tetrapoda". Contributions of the Walker Museum. 1: 193–236.
- ^ a b c d "The Dog Days of Dissorophids, Week 3: Platyhystrix". Bryan Gee, Ph.D. Retrieved 2023-03-03.
- ^ a b Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 52. ISBN 1-84028-152-9.
- 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
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