The cranial anatomy and relationships of <em>Secodontosaurus</em>, an unusual mammal-like reptile (Synapsida: Sphenacodontidae) from the Early Permian of Texas

Reisz, R. R. Berman, D. S. Scott, D. 1992 The cranial anatomy and relationships of <em>Secodontosaurus</em>, an unusual mammal-like reptile (Synapsida: Sphenacodontidae) from the Early Permian of Texas Zoological Journal of the Linnean Society 104 127-184 Varanopseidae Ophiacodontidae Edaphosauridae Haptodus Sphenacodon Ctenopsondylus Dimetrodon Secontosaurus Therapsida Osteology Maximum Parsimony Based on reanalysis of the original matrix. Reisz_etal_1992a