Fig. 1
From: Resolving the evolution of the mammalian middle ear using Bayesian inference
Dentary of a) Morganucodon with a mandibular middle ear based on the presence of a postdentary trough (redrawn from [48]); b Dentary of Liaoconodon with a partial mammalian middle ear based on the presence of Meckel’s groove (redrawn from [9]; c–e Dentary of the woylie, Bettongia penicillata at different developmental stages. c) presence of Meckel’s groove; d Meckel’s groove filled with the Meckel’s cartilage connecting the malleus to the dentary – this stage recapitulates or is similar to the partial mammalian middle ear found in some Cenozoic mammals; e individual showing a closed Meckel’s groove and absence of the connection, and hence, representing the definitive mammalian middle ear. The postdentary trough is not recapitulated during development in extant mammals. Orange, malleus; green, ectotympanic; blue, Meckel’s cartilage; light blue, incus; red, stapes; light green, incisor. Scale bar: 1 mm