Temporal range: Upper Cretaceous – Recent
|American crocodile (Crocodylus acutus)|
Crocodiles are the nearest living relatives to birds, because they are both survivors of the Archosaurs.
Crocodiles 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.