Crocodilia

Crocodilia; Temporal range: Upper Cretaceous – Recent
	American crocodile (Crocodylus acutus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
(unranked):	Archosauria
Superorder:	Crocodylomorpha
Order:	Crocodilia; Owen, 1842
Families
	Gavialidae; Alligatoridae; Crocodylidae;

The order Crocodilia is a group of archosaur reptiles. There are three living families of crocodilians.

Some crocodilians are crocodiles, alligators, gharials, and caimans.

Crocodilians are first found in the Upper Cretaceous period. They are descendents of a much wider group of archosaurs called the crocodylomorphs. These, in the Upper Triassic, were slender land-living animals.

The crocodylomorphs, in turn, were part of an even larger group, the Crurotarsi, which are first seen early in the Triassic.

Crocodilians are the the sister group of the dinosaurs. This means crocodilians are the closest living relatives to birds. They are both survivors of the Archosauria.