File talk:Echidna skeleton.jpg

Extra bones of the Echidna skeleton: interclavicle and coracoid. Source: https://en.wikipedia.org/wiki/Monotreme "The monotremes also have extra bones in the shoulder girdle, including an interclavicle and coracoid, which are not found in other mammals. Monotremes retain a reptile-like gait, with legs on their sides of, rather than underneath, their bodies. The monotreme leg bears a spur in the ankle region; the spur is not functional in echidnas, but contains a powerful venom in the male platypus."