Coelophysis
Late Triassic theropod dinosaur from the southwestern United States.
Coelophysis is an extinct genus of coelophysid theropod dinosaurs that lived during the late Triassic period, approximately 215 to 201.4 million years ago, in what is now the southwestern United States. It was a small, slenderly built, ground-dwelling, bipedal carnivore that could grow up to 3 m (9.8 ft) long, and it is one of the earliest known dinosaur genera. The genus is particularly notable for being one of the most specimen-rich dinosaur genera, with abundant fossil material. The type species, *C. bauri*, was originally placed in the genus *Coelurus* by Edward Drinker Cope in 1887 and described by him in 1889. Cope also named *C. longicollis* and *C. willistoni* from the same New Mexican material. The names *Longosaurus* and *Rioarribasaurus* are considered synonymous with *Coelophysis*. The original fossils were collected by David Baldwin in 1881 from three localities in Rio Arriba County, New Mexico, likely from the Chinle Formation near Ghost Ranch. In 1947, a major discovery at Ghost Ranch by Edwin H. Colbert and his team, including George Whitaker, uncovered numerous well-preserved skeletons. The genus *Megapnosaurus* was once considered a species within *Coelophysis*, but this interpretation has been challenged, and *Megapnosaurus* is now regarded as a valid genus. Scattered material representing similar animals has also been found in some Late Triassic and Early Jurassic formations worldwide.
- field
- Paleontology
- known_for
- One of the earliest known dinosaur genera; one of the most specimen-rich dinosaur genera
Lore & Background
Coelophysis was a small, slenderly built, ground-dwelling, bipedal carnivore that lived during the late Triassic period, approximately 215 to 201.4 million years ago, from the middle Norian to the Rhaetian age. Its remains are found in what is now the southwestern United States, and scattered material from similar animals has been discovered in Late Triassic and Early Jurassic formations worldwide. The genus is one of the earliest known dinosaur genera and is exceptionally rich in fossil specimens. The type species, *C. bauri*, was originally placed in the genus *Coelurus* by Edward Drinker Cope in 1887 and described by him in 1889. Cope later reclassified the material into the new genus *Coelophysis*, a name derived from Ancient Greek words meaning "hollow form." The names *Longosaurus* and *Rioarribasaurus* are synonymous with *Coelophysis*. The genus was once thought to include the species *Megapnosaurus*, but that interpretation has been challenged, and *Megapnosaurus* is now considered a valid separate genus. The original specimens were collected by David Baldwin in 1881 from three localities in Rio Arriba County, New Mexico, from a region near Ghost Ranch where the Chinle Formation is exposed below a gypsum layer of the Middle Jurassic Todilto Formation.
Reader's Guide
Coelophysis is significant as one of the earliest known dinosaur genera and one of the most specimen-rich, providing extensive insight into Late Triassic theropod anatomy and behavior. The abundance of specimens has allowed detailed study of growth, variation, and possible social behavior, though interpretations of species within the genus have been debated. The genus Megapnosaurus was once considered a species of Coelophysis, but that interpretation has been challenged and Megapnosaurus is now considered valid.
Did You Know?
- Coelophysis is one of the most specimen-rich dinosaur genera, with hundreds of skeletons found at Ghost Ranch.
- The names Longosaurus and Rioarribasaurus are synonymous with Coelophysis.
Frequently Asked Questions
What is Coelophysis?
Coelophysis was a small, slender, two-legged ground-dwelling carnivore and one of the earliest dinosaur genera ever recognized. It belongs to the theropod group and is a foundational species in early dinosaur history.
How big did Coelophysis get?
It could grow to roughly three meters (about 9.8 feet) in total length. Despite that, it was still a relatively small and lightly built predator compared to later theropods.
When and where did Coelophysis live?
It roamed the southwestern United States during the Late Triassic period, placing it well before the Jurassic and Cretaceous eras most people associate with dinosaurs.
Why is Coelophysis so important to paleontology?
As one of the earliest known dinosaur genera, it helps anchor the timeline of when dinosaurs first appeared. It is also among the most specimen-rich dinosaur genera, giving scientists an unusually large fossil record to work with.
Are there other names for Coelophysis?
Yes—Longosaurus and Rioarribasaurus are both considered synonyms, meaning they refer to the very same animal. All three names point to the same Late Triassic theropod.
More in Prehistoric Extinct Animals 1-24
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