Image: Australopithecus afarensis lower jaw Cast of the lower
jaw AL 400 1a, found between 1974 and 1977 at Hadar, Africa, by
Don Johanson. It is dated to about 3 million years old. It shows
characteristic features such as a relatively long and narrow
jaw, moderately-sized back molar teeth with human-like ‘Y-5’
pattern and relatively wide incisors. - Carl Bento - ©
Australian Museum