Olson, E. C. 1986 Relationships and ecology of the early therapsids and their predecessors 47-60 The Ecology and Biology of Mammal-like Reptiles Smithsonian Institution Press Washington Hotton, N. MacLean, P. D. Roth, J. J. Roth, E. C. Eotherapsids Eutherapsids Dinocephalians Dicynodonts Gorgonopsians Therocephalians Cynodonts Osteology Maximum Parsimony Based on reanalysis of the original matrix. Olson_1986ab