Coelophysis

Coelophysis; Temporal range: Late Triassic (middle Norian to Rhaetian),
	Mounted skeleton at the Cleveland Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Family:	†Coelophysidae
Genus:	†Coelophysis; Cope, 1889
Type species
	†Coelophysis bauri; (Cope, 1887a)
Synonyms
	Genus synonymy Longosaurus Welles, 1984 ; Rioarribasaurus Hunt & Lucas, 1991 ; Synonyms of C. bauri Coelurus bauri Cope, 1887a ; Tanystrophaeus bauri ; (Cope, 1887a) Cope, 1887b ; Rioarribasaurus colberti ; Hunt & Lucas, 1991 ; Syntarsus colberti ; (Hunt & Lucas, 1991) Paul, 1993 ; Dubious species designations Coelurus longicollis Cope, 1887a ; Tanystrophaeus longicollis ; (Cope, 1887a) Cope, 1887b ; Coelophysis longicollis ; (Cope, 1887a) Cope, 1889 ; Longosaurus longicollis Welles, 1984 ; Tanystrophaeus willistoni Cope, 1887b ; Coelophysis willistoni ; (Cope, 1887b) Cope, 1889 ;

Coelophysis (from Ancient Greek κοῖλος (koilos), "hollow", and φύσεις (fysis), "form") is an extinct genus of coelophysid theropod dinosaurs that lived approximately 215 to 201.4 million years ago during the late Triassic period from the middle Norian to Rhaetian age in what is now the southwestern United States. Megapnosaurus was once considered to be a species within this genus, but this interpretation has been challenged and the genus Megapnosaurus is now considered valid.

Coelophysis was a small, slenderly built, ground-dwelling, bipedal carnivore that could grow up to 3 m (9.8 ft) long. It is one of the earliest known dinosaur genera. Scattered material representing similar animals has been found worldwide in some Late Triassic and Early Jurassic formations.

The type species C. bauri, originally placed in the genus Coelurus by Edward Drinker Cope in 1887, was described by the latter in 1889. The names Longosaurus and Rioarribasaurus are synonymous with Coelophysis. Coelophysis is one of the most specimen-rich dinosaur genera.