Oudenodontidae Cope, 1871

Definition: All taxa more closely related to Oudenodon bainii Owen, 1860 a, than Rhachiocephalus magnus (Owen, 1876) Seeley, 1898, or Geikia elginensis Newton, 1893 .

Taxonomic comments: Recent research strongly supports a sister-group relationship between Oudenodon Owen, 1860 a, and Tropidostoma Seeley, 1889 (traditionally placed in separate family-level groups: Oudenodontinae van Hoepen, 1934, Oudenodontinae Cluver & King, 1983 [sic], and Oudenodontini King, 1988, versus Tropidostominae [sic, properly Tropidostomatinae] Cluver & King, 1983, and Tropidostomini [sic] King, 1988), to the extent that the generic distinction between these taxa has been called into question (Cluver & King 1983; Botha & Angielczyk 2007). Here, we unite these taxa and the Russian genus Australobarbarus Kurkin, 2000, (following Angielczyk & Kurkin 2003a, 2003b) in Oudenodontidae, based on the earliest available name for this group ( Oudenodontidae Cope, 1871, validated under Article 12.2.4 of the Code).

Revised diagnosis: The analyses of Angielczyk (2007), Fröbisch (2007), and Fröbisch & Reisz (2008) identified two autapomorphies diagnostic of Oudenodontidae: (1) interpterygoid vacuity long and reaches the level of the palatal exposure of the palatines; (2) postparietal contributes to the intertemporal skull roof.