Emydopidae (van Hoepen, 1934) Cluver & King, 1983

Definition: All taxa more closely related to Emydops arctatus (Owen, 1876) Broom, 1913 a, than Cistecephalus microrhinus Owen, 1876.

Taxonomic comments: Cluver & King (1983) established the family-level taxa Emydopidae and Emydopinae to contain Emydops Broom, 1912 b, despite the fact that van Hoepen (1934) had already named this taxon as the subfamily Emydopsinae [sic]. Phylogenetic analyses of dicynodonts (e. g., Angielczyk 2007; Fröbisch 2007; Fröbisch & Reisz 2008) consistently recover Emydops as the sister-group to the other wellknown emydopoids (Myosaurus, Kingoria, and cistecephalids), so we restrict the external specifier to Cistecephalus Owen, 1876.

Revised diagnosis: Two autapomorphies of Emydopidae are present in the data set of Angielczyk (2007): (1) lateral anterior palatal ridges present; (2) upper postcanine teeth located near lateral margin of the maxilla. One autapomorphy of Emydopidae is present in the data set of Fröbisch (2007): (1) maxillary non-caniniform teeth located near lateral margin of the maxilla. The addition of Emydops oweni to the data set of Fröbisch & Reisz (2008) renders the status of that character uncertain, because it could not be scored using the available specimens of E. oweni. However, one emydopid autapomorphy does exist in the data set of Fröbisch & Reisz (2008): (1) squared-off profile of occiput in posterior view present. Recent diagnoses of Emydops itself can be found in Keyser (1993; called Emydoses therein), King & Rubidge (1993), Ray (2001), and Fröbisch & Reisz (2008), with additional information in Angielczyk et al. (2005). The jaw of Emydops is the single most distinctive part of its skeleton, and is characterized by a shovel-shaped symphysis, weak posterior dentary sulci, a small number of medially located postcanine teeth, and a large, triangular lateral dentary shelf.