Reptile

Reptiles; Temporal range: Pennsylvanian–present, 312–0 mya
	Clockwise from above left: Green sea turtle (Chelonia mydas), Tuatara (Sphenodon punctatus), Nile crocodile (Crocodylus niloticus), and Sinai agama (Pseudotrapelus sinaitus)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Sauropsida
Class:	Reptilia; Laurenti, 1768
Living groups
	Lepidosauria (lepidosaurs) Rhynchocephalia (tuatara and relatives); Squamata (lizards and snakes); ; Testudines (turtles); Archosauria (archosaurs) Crocodilia (crocodilians); Aves (birds) (included in cladistic analyses, but excluded in traditional taxonomy); ; See text for extinct groups.
	Global reptile distribution (excluding birds)

Reptile is the common name for one of the main groups of land vertebrates. It is not used so much by biologists, who use more accurate terms.

The name "reptile" comes from Latin and means "one who creeps". All living reptile species are cold blooded, have scaly skin, and lay cleidoic eggs.^[1]^[2] They excrete uric acid (instead of urea), and have a cloaca. A cloaca is a shared opening for the anus, urinary tract and reproductive ducts. Reptiles also share an arrangement of the heart and major blood vessels which is different from that of mammals.^[3] Birds have all of these features.

Many important groups of reptiles are now extinct, for example the mosasaurs. We used to say the dinosaurs were extinct, but they survive in the form of their feathered descendants (birds). Ancient reptiles that do survive include the turtles, the crocodiles and the Tuatara, the lone survivor of its group. The great majority of present-day reptiles are snakes and lizards.

The study of living reptiles is called herpetology.

↑ Some give birth to live young, with the cleidoic eggs developing internally.
↑ 2008. "Squamata Suborder: Serpentes". The University of Georgia Museum of Natural History. [1] Archived 2010-06-13 at the Wayback Machine
↑ Goodrich E.S. 1930. Studies on the structure and development of vertebrates. Macmillan, London.

[1] Some give birth to live young, with the cleidoic eggs developing internally.

[2] 2008. "Squamata Suborder: Serpentes". The University of Georgia Museum of Natural History. [1] Archived 2010-06-13 at the Wayback Machine

[3] Goodrich E.S. 1930. Studies on the structure and development of vertebrates. Macmillan, London.

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