Nepedia
Back to Discover
Advanced Reader
🧬

Coelophysis

life science Maturity 5-7 war conflict Next article →

This article covers sensitive topics: war_conflict. Parents can manage visibility in Parental Controls.

Coelophysis was an extinct genus of theropod dinosaur.

Coelophysis skeleton
Coelophysis skeleton

This group of dinosaurs lived during the late Triassic period. Specifically, they existed from the middle Norian to the Rhaetian age. This was approximately 215 to 201.4 million years ago. They lived in what is now the southwestern United States. Coelophysis is considered one of the earliest known dinosaur genera. Because they were theropods, they were meat-eating animals. They were small, slenderly built, and bipedal, meaning they walked on two legs.

Coelophysis size
Coelophysis size

They were ground-dwelling animals that could grow to significant lengths.

The name Coelophysis comes from Ancient Greek words. It combines "koilos," meaning hollow, and "fysis," meaning form. This name refers to the hollow nature of their bones. These dinosaurs were built for speed and agility. They were carnivores that hunted on the ground. While they were primarily found in the American Southwest, scattered remains of similar animals have been found in formations worldwide. This suggests they were part of a widespread group of early dinosaurs during the Late Triassic and Early Jurassic periods.

Scientists have identified different species within the Coelophysis genus.

Coelophysis bauri
Coelophysis bauri

The type species is Coelophysis bauri. For a time, the genus Megapnosaurus was thought to be a species of Coelophysis. However, researchers now consider Megapnosaurus to be a valid, separate genus. Cope originally described three species: C. bauri, C. longicollis, and C. willistoni. These species varied in size. C. longicollis was the largest, while C. willistoni was the smallest. Some researchers have even suggested there might be more than three species present based on bone size.

The history of discovering Coelophysis is quite complex.

Coelophysis neotype skull
Coelophysis neotype skull

In April 1887, paleontologist Edward Drinker Cope described vertebrate remains from New Mexico. At first, he placed them in the genus Coelurus. He even thought they might be related to a reptile called Anchisaurus. In 1887, he briefly moved them to a different genus called Tanystrophaeus. He did this because of similarities in the vertebrae, or the bones of the spine. Eventually, he realized the vertebrae were not all caudal vertebrae, which are tail bones. In 1889, he established the new genus Coelophysis. The original fossils were collected by David Baldwin in 1881 from Rio Arriba County, New Mexico.

One of the most significant discoveries occurred at Ghost Ranch.

Ghost Ranch Coelophysis Quarry
Ghost Ranch Coelophysis Quarry

In 1947, Edwin H. Colbert led a field crew to explore the Chinle Formation. On June 22, 1947, George Whitaker found bone fragments, including a claw. This led to the discovery of a massive fossil layer. This layer contained hundreds of Coelophysis skeletons in a single concentration. One scientist called it the greatest find ever made in the Triassic of North America. The team excavated seven large blocks containing many skeletons. They also collected about 105 smaller blocks. These fossils provided an incredible amount of data for studying early dinosaurs.

Decades later, the quarry was reopened for further study.

CMNH Coelophysis Block
CMNH Coelophysis Block

After the site was abandoned in 1948, it sat undisturbed for 32 years. In 1981, David Berman proposed reopening the quarry. The work continued through 1982. During this time, 16 large blocks were excavated. All but one were removed from the site. The final block stayed at the site until 1985. This second wave of excavation helped scientists understand the population better. It showed that the fossils included hundreds of individuals of various ages and sizes. Some researchers noted variations in the proportions of these individuals.

Modern paleontologists still debate the exact classification of Coelophysis.

Postosuchus, Coelophysis, and Placerias
Postosuchus, Coelophysis, and Placerias

Some scientists, like Kevin Padian, have suggested it might be a "metataxon." This means it may lack unique characteristics that define a single group. Others, like Adrian P. Hunt and Spencer G. Lucas, argued it is a "nomen dubium." This term describes a name that is of uncertain or doubtful application. They believed the type material could not be clearly distinguished from other theropods. Because of this, they named a new taxon, Rioarribasaurus colberti, for the complete specimens found at the Ghost Ranch quarry. This new name honors both the location and Edwin Colbert's work.

667 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (17)
File:Ghost Ranch Coelophysis Quarry.jpg
Ghost Ranch Coelophysis Quarry.jpg
File:Coelophysis bauri.jpg
Coelophysis bauri.jpg
File:Hayden Quarry.png
Hayden Quarry.png
File:Replica of coelurosaur bone casts from Middletown, Connecticut.jpg
Replica of coelurosaur bone casts from...
File:Snout and front teeth of Coelophysis and Syntarsus.jpg
Snout and front teeth of Coelophysis and...
File:Coelophysis size.jpg
Coelophysis size.jpg
File:Coelophysis neotype skull.jpg
Coelophysis neotype skull.jpg
File:Coelophysis skeleton.jpg
Coelophysis skeleton.jpg
File:Coelophysis sp skull Harvard.jpg
Coelophysis sp skull Harvard.jpg
File:Coelophysis cast.jpg
Coelophysis cast.jpg
File:Coelophysis Jeff Martz.jpg
Coelophysis Jeff Martz.jpg
File:Coelophysis with crocodylomorph bones AMNH.jpg
Coelophysis with crocodylomorph bones AMNH.jpg

+ 5 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.