Misplaced Pages

Ctenorhachis Temporal range: Early Permian, 290.1–279.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Family:	†Sphenacodontidae
Genus:	†Ctenorhachis Hook & Hotton, 1991
Type species
†Ctenorhachis jacksoni Hook & Hotton, 1991

Ctenorhachis (Greek for "comb spine") is an extinct genus of the family Sphenacodontidae. Ctenorhachis lived in the Early Permian epoch. Ctenorhachis was related to Dimetrodon, but did not belong to the same subfamily as Dimetrodon and Sphenacodon, being a more basal member of Sphenacodontidae. Two specimens are known that have been found from the Wichita Group outcropping in Baylor and Archer counties, north-central Texas. Only the vertebrae and pelvis are known. Articulated vertebrae from the holotype specimen possess blade like neural spines that are greatly enlarged, although not nearly to the extent that can be seen in more derived sphenacodontids such as Dimetrodon and Secodontosaurus, in which they form a large sail. The pelvis is nearly identical to that of Dimetrodon. As suggested in the original description of the genus, Ctenorhachis may represent a short-spined sexual dimorph, although the authors find this unlikely.

See also

• List of pelycosaurs

References

1. Benson, R.J. (2012). "Interrelationships of basal synapsids: cranial and postcranial morphological partitions suggest different topologies". Journal of Systematic Palaeontology. 10 (4): 601–624. doi:10.1080/14772019.2011.631042. S2CID 84706899.
2. Hook, R. W. and N. Hotton (1991). A New Sphenacodontid Pelycosaur (Synapsida) from the Wichita Group, Lower Permian of North-Central Texas. Journal of Vertebrate Paleontology 11(1):37-44.

v t e Synapsida
Kingdom: Animalia Phylum: Chordata Superclass: Tetrapoda Clade: Amniota Tetrapodomorpha see Tetrapodomorpha Reptiliomorpha see Reptiliomorpha Synapsida see below↓
Synapsida Synapsida †Diadectomorpha? †Caseasauria? Eothyrididae Asaphestera? Eothyris Oedaleops Vaughnictis Caseidae Alierasaurus Angelosaurus Arisierpeton Callibrachion Casea Caseoides Caseopsis Cotylorhynchus Datheosaurus Ennatosaurus Eocasea Euromycter Lalieudorhynchus Martensius Oromycter Phreatophasma Ruthenosaurus Trichasaurus Eupelycosauria †Varanopidae? Apsisaurus Archaeovenator Ascendonanus Eoscansor Dendromaia Nitosaurus? Pyozia Thrausmosaurus Mesenosaurinae Anningia Cabarzia Elliotsmithia Heleosaurus Mesenosaurus Microvaranops Varanodontinae Aerosaurus Mycterosaurus? Ruthiromia Tambacarnifex Varanops Varanodon Watongia Metopophora see below↓ Incertae sedis †Dimacrodon †Driveria †Gorgodon †Knoxosaurus †Mastersonia †Protoclepsydrops?
Metopophora †Ophiacodontidae Archaeothyris Baldwinonus Clepsydrops Echinerpeton Ophiacodon Stereophallodon Stereorhachis Varanosaurus Haptodontiformes †Ianthodon †Milosaurus †Edaphosauridae Bohemiclavulus Edaphosaurus Glaucosaurus Gordodon Ianthasaurus Lupeosaurus Melanedaphodon Ramodendron Remigiomontanus Xyrospondylus Sphenacodontia †Cutleria †Haptodus †Hypselohaptodus †Kenomagnathus †Tetraceratops †Palaeohatteriidae Palaeohatteria Pantelosaurus Sphenacodontoidea †Shashajaia †Sphenacodontidae Cryptovenator Ctenorhachis Ctenospondylus Cutleria? Dimetrodon Eosyodon Macromerion Neosaurus Secodontosaurus Sphenacodon Steppesaurus? Tappenosaurus? Tetraceratops? Therapsida see below↓
Therapsida Therapsida †Raranimus †Biarmosuchia see Biarmosuchia †Dinocephalia see Dinocephalia †Anomodontia see Anomodontia includes dicynodonts †Gorgonopsia see Gorgonopsia Eutheriodontia †Therocephalia see Therocephalia Cynodontia see Cynodontia includes mammals Incertae sedis †Dinosaurus †Kamagorgon †Niaftasuchus
See also: Pelycosauria Phthinosuchia Theriodontia Category

This Synapsida-related article is a stub. You can help Misplaced Pages by expanding it.

• v
• t
• e

• Sphenacodontidae
• Prehistoric synapsid genera
• Cisuralian synapsids of North America
• Taxa named by Nicholas Hotton III
• Fossil taxa described in 1991
• Artinskian genus first appearances
• Artinskian genus extinctions
• Synapsid stubs