Pair of mounted skeletons of Dimetrodon, copyright D’Arcy Norman.

Belongs within: Synapsida.
Contains: Therapsida.

The Sphenacodontidae are a group of carnivorous ‘pelycosaurs’ known from the later Carboniferous to the Middle Permian, suggested by Kemp (1988) to be paraphyletic to the therapsids.

    |  i. s.: SecodontosaurusBH04
    |         Sphenacodon Marsh 1878D07
    |           |--S. ferociorD07
    |           `--S. ferox Marsh 1878C07
    |--Haptodus garnettensis Currie 1977K88, B93
       `--Dimetrodon Cope 1878K88, BH04
            |--*D. incisivus Cope 1878 (see below for synonymy)C07
            |--D. angelensis Olson 1962B93
            |--D. biradicatusC07
            |--D. dollovianus (Cope 1884) [=Embolophorus dollovianus]C07
            |--D. giganhomogenes Case 1907C07
            |--D. gigas (Cope 1878) [=Clepsydrops gigas]C07
            |--D. grandisN85
            |--D. limbatusBH04
            |--D. longiramus Case 1907C07
            |--D. macrospondylus (Cope 1884) [=Clepsydrops macrospondylus]C07
            |--D. milleriBH04
            |--D. natalisBH04
            |--D. navajovicus Case 1907C07
            |--D. obtusidens (Cope 1880) [=Theropleura obtusidens]C07
            |--D. occidentalisBH04
            |--D. platycentrus Case 1907C07
            `--D. teutonis Berman et al. 2001BH04

*Dimetrodon incisivus Cope 1878 [incl. Clepsydrops limbatus Cope 1877, C. (Embolophorus) limbatus; incl. Dimetrodon rectiformis Cope 1878, D. semiradicatus Cope 1881]C07

*Type species of generic name indicated


[B93] Benton, M. J. 1993. Reptilia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 681–715. Chapman & Hall: London.

[BH04] Berman, D. S., A. C. Henrici, S. S. Sumida & T. Martens. 2004. New remains of Dimetrodon teutonis (Synapsida: Sphenacodontidae) from the Lower Permian of Germany. Annals of Carnegie Museum 73 (2): 48–56.

[C07] Case, E. C. 1907. Revision of the Pelycosauria of North America. Carnegie Institute of Washington Publication 55: 1–176, 35 pls.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[K88] Kemp, T. S. 1988. Interrelationships of the Synapsida. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 2. Mammals pp. 1–22. Clarendon Press: Oxford.

[N85] Norman, D. 1985. The Illustrated Encyclopedia of Dinosaurs. Salamander Books: London.

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