Filozoa

Crocodilia (or Crocodylia) is an order of large reptiles that appeared 83.5 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 known survivors of the Archosauria. Members of the crocodilian total 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.

Although the term 'crocodiles' is sometimes used to refer to alligators, caiman, and gharials, or even to their distant prehistoric relatives the marine crocodiles, a less ambiguous vernacular term for this group is 'crocodilians'.

The group is often spelled 'Crocodylia' for consistency with the genus Crocodylus (Laurenti, 1768). However, Richard Owen used the -i- spelling when he published the name in 1842, so it is generally preferred in the scientific literature.^{[citation needed]} The -i- spelling is also a more accurate Latinization of the Greek κροκόδειλος (crocodeilos, literally "pebble-worm", referring to the texture and shape of the animal). However, the y-spelling is increasingly common, especially in the context of phylogeny-based names in which Crocodylia is limited to the crown group.