Coelophysis was a Nine Foot Long Carnivore

Some 216.5 to 203.6 million years ago during the late Triassic period Coelophysis walked the Earth. As one of the earliest known genera of dinosaurs this nine foot long carnivore can teach us a lot about the evolution of dinosaurs. Below we will take a look at everything you ever wanted to know about the dinosaur that would become New Mexico’s state fossil.

Quick Facts

What Did Coelophysis Look Like?

Coelophysis was a Bipedal Saurischian Dinosaur

The name “Coelophysis” translates to mean “hollow form” and refers to the hollow bones of this early biped. This smaller dinosaur species measured in at around 9.8 feet long and stood at around three feet high. Despite its short stature and 55 lb weight, this carnivore was a force to contend with. While this dinosaur was an early Theropod, it already resembled a smaller version of the later Theropod giants. Coelophysis stands out in paleontology as being the earliest dinosaur specimen with a wishbone. To date researchers have identified two types of “build” for the Coelophysis body, a slender gracile form and a more robust form. This difference in build is seen as a type of sexual dimorphism with the females being the more gracile of the species. There are currently three potential species of Coelophysis: C. Rioarribasaurus, C. Megapnosaurus and C. Podokesaurus. The only species officially recognized at this time is C. Rioarribasaurus.

Physical Attributes of Coelophysis

Coelophysis had short arms and longer hind legs like other Theropod specimens. The hind legs however, were much thinner than those of later Theropod species and combined with the lighter weight of Coelophysis contributed to a higher top speed on land. The long tail of this carnivore would have provided balance while standing on the hind legs, in addition to allowing rapid changes of direction when moving quickly. Both the feet and hands of this dinosaur featured three digits each and all had sharp claws. Uniquely, the forelimbs featured a fourth digit that had become part of the hand. The long neck of Coelophysis was long and slender and would have allowed for rapid movement of the head and more streamlined movement through trees while hunting prey.

Eyesight was important to Coelophysis for tracking smaller prey items and as such the eyes were large in comparison to the small, slender head. The narrow skull was filled with small but sharp teeth which lead researchers to believe that this carnivore likely fed on smaller lizards. It may be possible that this theropod may have hunted and attacked larger prey in packs; there is no evidence to support this theory to date.  The smaller slender skull sets Coelophysis apart from other Theropods that came in later years. In addition to skull differences, the smaller size of this carnivore makes it nearly unrecognizable as a relative of Tyrannosaurus Rex.

The Hollow Bones of Coelophysis

The skull of Coelophysis featured large fenestrae which made it much lighter and easier to support on the thin sigmoid curved neck. The weight lightening fenestrae weren’t the only light feature of this dinosaur however, Coelophysis had hollow bones. While the hollow bones of Coelophysis were believed to be unique to Coelophysis by American paleontologist Edward Drinker Cope, it was later revealed that this was not the case. The lighter bones would have permitted this smaller dinosaur to move quickly as well as support its weight on two thinner hind legs.

What Did Coelophysis Eat?

The thin teeth of Coelophysis had serrated edges which when combined with large claws made this a meat eater no smaller creature would want to run in to. As a carnivore, Coelophysis killed its own prey but also scavenged on carrion when available. Paleontologists believe that this Triassic period dinosaur may even have eaten its young when no other food sources were available. Proof of this cannibalism can be found in the fossilized gut contents of a Coelophysis specimen that show remains of another Coelophysis! As hatchlings these bipeds were much less formidable and would have snapped up smaller insects and lizards to feed themselves.

How Did Coelophysis Move?

Like all Theropods, Coelophysis was bipedal relying on its long back legs to move. The forelimbs of this dinosaur may have been longer than those of T-Rex but they were still not long enough to support quadrupedal movement. Hollow bones and long slender legs mean that Coelophysis was a fast moving predator. Using its estimated body mass as well as measurements from a complete specimen, researchers estimate a stride length of 2.5 feet. The feet of this smaller dinosaur measured in at only four inches long, yet this Theropod is believed to have had a top speed of between 25 to 30 miles per hour.

Coelophysis Predators

Coelophysis may have been a carnivore but its smaller size meant that it was not the top predator in its ecosystem. Researchers believe that Coelophysis would have been prey to Postosuchus, Smilosuchus and semi-aquatic Phytosaurs.

The History of Discovering Coelophysis

Where Did Coelophysis Live?

Coelophysis lived during the late Triassic period some 216.5 to 203.6 million years ago.  Researchers believe that this small theropod lived on river floodplains where it walked alongside crocodilian-like Phytosaurs. Coelophysis lived in what is now known as Western North America in New Mexico and Arizona.

Coelophysis Specimen Discovery

The first specimen of Coelophysis was discovered in 1881 by David

Baldwin, an amateur fossil collector. This type specimen

was named in 1889 by Edward Drinker Cope as Coelophysis bauri, after a fossil collector that worked for Cope, Baur. While the first specimen recovered was interesting, it simply did not provide enough information to create an accurate picture of Coelophysis. In 1947 however, a Coelophysis graveyard was discovered at the Ghost Ranch in New Mexico close to the dig site of the original fossil. Paleontologists believe that due to the sheer number of fossils found and their degree of preservation, that the Ghost Ranch fossils perished in a flash flood. The flash flood circumstances preserved the Coelophysis specimens so well that one of the many complete fossils found at Ghost Ranch replaced the original type specimen.

The Ghost Ranch Coelophysis finding was the most significant finding in terms of making progress in our knowledge about this dinosaur but it is not the only discovery since the initial finding. Additional Coelophysis specimens have been discovered in Arizona and New Mexico, these specimens include both adult and juvenile dinosaurs. Some paleontologists also believe that footprints of this species have been located in Connecticut Valley.

The Importance of the Coelophysis

Coelophysis is a significant discovery for the world of paleontology for a number of reasons. One of the biggest fascinations with this species is that it allows researchers to follow the development of the Theropod from its earlier forms to the better known Tyrannosaurus Rex. Additionally, Coelophysis is one of the most primitive known carnivorous dinosaurs which makes it a fascinating specimen to study overall.