Figure 6 in Osteology and phylogenetic position of the diminutive 'microsaur' Odonterpeton triangulare from the Pennsylvanian of Linton, Ohio, and major features of recumbirostran phylogeny

Figure 6. Palatal views of selected early amniotes, including recumbirostrans, focusing on the structured pterygoid (peach coloured). A, palate of the early captorhinid eureptile, Captorhinus, showing a triradiate pterygoid with a distinct, posteroventrally descending and tooth-bearing transverse flange of the pterygoid (Fox & Bowman, 1966). B, palate of an early-diverging synapsid, Eothyris, showing a triradiate pterygoid with a weakly posteriorly oriented, ventrally descending and tooth-bearing transverse flange of the pterygoid (Reisz et al., 2009). C, palate of an early eureptile, Protorothyris, showing a triradiate pterygoid with an almost straight, ventrally descending and tooth-bearing transverse flange of the pterygoid (Clark & Carroll, 1973). D, palate of an early eureptile, Paleothyris, showing a triradiate pterygoid with a weakly posteriorly oriented, ventrally descending and tooth-bearing transverse flange of the pterygoid (Carroll, 1969). E, palate of an early parareptile, Acleistorhinus, showing a triradiate pterygoid with a nearly straight, perhaps slightly anteriorly canted, ventrally descending and tooth-bearing transverse flange of the pterygoid (deBraga & Reisz, 1996). F, palate of the araeoscelid eureptile Petrolacosaurus, showing a less distinct, anteriorly oriented and tooth-bearing transverse flange of the pterygoid (Reisz, 1977). G, palate of a putative captorhinid reptile, Opisthodontosaurus, showing a triradiate pterygoid with a somewhat straight, shallowly descending, lightly denticulated, transverse flange of the pterygoid (Reisz et al., 2015).