By: Staff

Updated on: 28/03/2022

The Coelophysis is the oldest dinosaur in the continent of North America and roamed the earth during the Late Triassic Period. Being discovered about 130 years back, it is also one of the oldest known dinosaur genera in the world. They get their name ‘Coelophysis’ from the Greek words ‘koilos’, meaning ‘hollow’, and ‘physis’, meaning ‘form’. Hence, the name “hollow form” is a reference to the reptile’s hollow vertebrae.

Scientific Classification

Type Species:†Coelurus bauri

Quick Facts

Geological Period:About 216 to 203 mya (during the Late Triassic Period)
Size:Up to 3 meters (9.8 feet) (head to tail-tip length)
Height:‎About 1.25 meters (4 feet) (at the shoulders)
Weight:Estimated weight of the ‘robust’ form (probably the male) – 20 kg; Estimated weight of the ‘gracile’ form (probably the female) – 15 kg
Average Lifespan:Unknown
Location/Distribution (where did they live):Texas and throughout the Southwestern U.S.
Habitat & Climate/Environment:Preferred an arid desert-like climate
Birth Type (Reproduction):Oviparous

History and Discovery

Coelophysis Dinosaur

It was in 1889 that the Coelophysis bauri was named for the first time by paleontologist Edward Drinker Cope. However, the remains of the specimens found by that time were not enough to have conclusive evidence about the nature and characteristics of the new species.

Decades later, in 1947, in northern New Mexico’s Chama River valley, an entire area scattered with the remains of the creatures was discovered jointly by scientists Edwin Colber and George Whitaker.


To their surprise, quantities of fossils were unearthed, and many of them were complete skeletons. Such a striking and successful discovery made them conclude that this site housed a large group of these reptiles that gathered at a drying waterhole in order to obtain water since, during this period (Triassic era), there was a scarcity of water resulting from the uprising and fluctuating dry and hot temperatures.

Prior to their death (or maybe even after dying), they might have been fallen victims to a flash flood, resulting in their burial. Soon after this discovery, the Coelophysis went on to be one of the most famous dinosaurs.

Physical Description

Coelophysis Fossil
Coelophysis Skeleton

Coelophysis was a delicately-built carnivore with a pair of slender legs bearing three-toed feet. Its pair of arms had four fingers each, although the last digits were considerably small. The head/skull of the creature bore a strong jaw lined with small but sharp and serrated teeth.

Practically, the dinosaur, was rather short, compared to the other medium-sized to gigantic reptiles that roamed the planet. Quite like the birds, they had hollow bones and skull, which allowed them to run at great speed.

Coelophysis Skull

The dinosaur’s large eyes were adapted to help them see clearly at long distances to watch out for predators and prey. Interestingly, they might have even displayed sexual dimorphism which was hypothesized by the paleontologists after two types of Coelophysis were discovered, with one being rather robust (probably the male), and the other relatively gracile (maybe the female).

The Coelophysis’ tail was long, but was designed with such interlocking structures that prevented them from moving it vertically (but side to side). Probably, by evolution, this helped the creature to use it as a rudder while running at top speed.


Coelophysis Images
Coelophysis Pictures

The Coelophysis would prefer warm environments that were more tropical with frequent rain. They were predators. These creatures are thought to have preyed on animals that were smaller by size than it was.

Though, there are also evidence which made the biologists opine that they might have also attacked larger creatures like thecodonts, prosauropods, etc., from time to time.

Picture of a Coelophysis

However, these carnivores may have hunted large prey in considerably larger packs, though there is no concrete evidence as yet in support of this defensive pack behavior. It is only the mass finding in New Mexico that might support this nature.

Discovery of a baby near the abdomen region of an adult has also stirred up the probability of these creatures cannibalizing their young ones. However, there are also chances that the juvenile Coelophysis might have been fossilized under an adult specimen. There is no other evidence, currently, to support their cannibalistic nature.

Diet: What did they Eat

These carnivores would rely upon a variety of arthropods (i.e., insects that were large during the era), smaller reptiles, and fish.

Interesting Facts

Coelophysis Teeth
  • In 1981, the Coelophysis has been officially declared as the state fossil of New Mexico.
  • On 22 January, 1998, a Coelophysis skull was sent in the space shuttle named ‘Endeavor’ in its mission STS-89, which became the ‘second dinosaur’ in space (only after the skull of the Maiasaura that was sent in the mission STS-51-F).
  • At present, the prehistoric reptile is the logo of the New Mexico Museum of Natural History.
  • The Coelophysis is one of the most well-known dinosaurs in literature, with their mention and references in many literary works (especially science fictions) from around the world.
  • In the opening episode of the computer-animated television miniseries ‘Walking with Dinosaurs’, the Coelophysis was shown hunting cynodonts, lungfish, and eating a dying Postosuchus, as also, each other, during an ancient drought.
  • The Coelophysis also appeared in the American animation/documentary television program ‘When Dinosaurs Roamed America’.

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