In amphibians & stem reptiles, the dermal skull roof is unbroken except for openings for eyes & nasal openings. In these animals, the temporal muscles which close the jaw are shut inside the solid ...

Jin Meng at the American Museum of Natural History and his colleagues discovered well-preserved skeletons of a shrew-sized ancient ... The middle ear bones of this animal are at the base of its jaw, ...

The extended lower jaw of Alienacanthus, twice as long as the skull, is unique among placoderms and extremely rare in other living and fossil groups. In most animals, jaw protrusion is seen in the ...

Modern mammals evolved from within a group of animals called Cynodonts. These had a jaw joint consisting of two separate bones - the quadrate of the skull and the articular in the lower jaw and ...