Fig. 17. Petromus typicus AMNHM 34393 in Basicranial Morphology And Relationships Of Antillean Heptaxodontidae (Rodentia, Ctenohystrica, Caviomorpha)

Fig. 17. Petromus typicus AMNHM 34393, right auditory region (rev.). Note straplike process separating the small tympanic fenestra from the meatus. The former was initially scored as a (large) foramen for meatal innominate vasculature. However, closer inspection revealed that a plug of meatal tissues was still in place, and only after pulling it away on the opposite side (not photographed) did it become evident that a notchlike tympanic fenestra (C1:2) was present, like that of some caviomorphs. In some other specimens (e.g., AMNHM 165295) the fenestra has a more complex shape, but is still scored as present.