Sphenacodontoidea

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Sphenacodontidae
Therapsida

Referensi:
Hurlburt G (1999), Comparison of body mass estimation techniques, using Recent reptiles and the pelycosaur Edaphosaurus boanerges. J. Vert Paleontol. 19: 338– 350.
Modesto SP (1994), The Lower Permian synapsid Glaucosaurus from Texas. Paleontology 37: 51–60.
Modesto SP & RR Reisz (1990a), Taxonomic status of Edaphosaurus raymondi Case. J. Paleontol. 64: 1049-1051.
Reisz RR (1972), Pelycosaurian reptiles from the Middle Pennsylvanian of North America. Bull. Mus. Comp. Zool. 144: 27-62.
Rubidge BS & CA Sidor (2001), Evolutionary patterns among Permo-Triassic therapsids. Ann. Rev. Ecol. Syst. 32: 449-480

Sumber gambar : http://picasaweb.google.com/gnallendran/Hi_res_Wallpapers#5100393746705306898