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.

Crocodilians are the nearest living relatives to birds, because they are both survivors of the Archosaurs.

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 forms, the sister group of the dinosaurs. Now birds are their closest living relatives.

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

• Sauropsida
  • Archosauria
    • Crurotarsi
      • Crocodylomorphs
        • Crocodilia