The angular is a large bone in the lower jaw (mandible) of amphibians and reptiles (birds inclused), which is connected to all other lower jaw bones: the dentary (which is the entire lower jaw in mammals), the splenial, the suprangular, and the articular. It is homologous to the tympanic bone bone in mammals, due to the incorporation of several jaw bones into the mammalian middle ear early in mammal evolution.