Entotympanics, Ontogeny and Primates

Abstract

Ontogenetic investigations confirm that independent entotympanics are absent in living primates. Although cartilage occurs in the petrosal tympanic processes of some primates, the assumption that a suppressed entotympanic is thereby indicated can be adequately refuted according to embryological canons of interpretation. Problems regarding the homologies of different entotympanics, largely ignored by paleontologists and system- atists, reduce or negate their taxonomic valency for all but closely related groups. Until such puzzles are resolved, the possible but doubtful existence of entotympanics in plesiadapoids and inferred pre-primate ancestors cannot buttress claims for alleged ties between primates and certain entotympanic-bearing eutherians (principally bats, colugos and tree shrews).