An order of reptiles including the crocodiles, gavials, alligators, and many extinct kinds.

crocodiles; alligators; caimans; gavials

Crocodilia is an order of large reptiles that appeared about 84 million years ago in the Late Cretaceous Period (Campanian stage). They are the closest living relatives of birds, as the two groups are the only survivors of the Archosauria.http://animaldiversity.ummz.umich.edu/site/accounts/information/Crocodilia.html Members of the crocodilian stem group, the clade Crurotarsi, appeared about 220 million years ago in the Triassic Period and exhibited a wide diversity of forms during the Mesozoic Era.