Fig. 1

Alizarin red/Alcian blue staining of guinea pig, mouse and opossums mandibles. a–c The coronoid process is a distinct part of the dentary in mammals such as the mouse (Mus musculus) and opossum (Mondelphis domestica) during development and in the adult (a, b), whereas the guinea pig (Cavia porcellus) displays a coronoid process comparable with the mouse in embryonic stages (E37 presented in c), but only has a rudimentary process in adults. d Conditional deletion of Pax9 in neural crest lineage cells results in a loss of the coronoid process [8]; Arrowheads: location of coronoid process; asterisk location of condylar process, double dagger location of absent coronoid process