Facts About Coelophysis

01
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How Much Do You Really Know About Coelophysis?

coelophysis
Wikimedia Commons

One of the best-represented theropod (meat-eating) dinosaurs in the fossil record, Coelophysis holds an important place in the history of paleontology. On the following slides, you'll discover 10 fascinating Coelophysis facts.

02
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Coelophysis Lived During the Late Triassic Period

coelophysis
Wikimedia Commons

The eight-foot-long, 50-pound Coelophysis prowled southwestern North America well before the golden age of dinosaurs: the end of the Triassic period, about 215 to 200 million years ago, right up to the cusp of the ensuing Jurassic. At that time, dinosaurs were far from the dominant reptiles on land; in fact, they were probably third in the terrestrial pecking order, behind crocodiles and archosaurs (the "ruling lizards" from which the first dinosaurs evolved).

03
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Coelophysis Was a Recent Descendant of the Very First Dinosaurs

eoraptor
Eoraptor, one of the first dinosaurs (Wikimedia Commons).

As early as Coelophysis appeared on the scene, it wasn't quite as "basal" as the dinosaurs that preceded it by 20 or 30 million years, and of which it was the direct descendant. These middle Triassic reptiles, dating from about 230 million years ago, included such important genera as Eoraptor, Herrerasaurus and Staurikosaurus; as far as paleontologists can tell, these were the first true dinosaurs, only recently evolved from their archosaur predecessors.

04
of 11

The Name Coelophysis Means "Hollow Form"

coelophysis
Nobu Tamura

Granted, Coelophysis (pronounced SEE-low-FIE-sis) isn't a very catchy name, but naturalists of the mid-19th century adhered strictly to form when assigning names to their discoveries. The name Coelophysis was bestowed by the famous American paleontologist Edward Drinker Cope, who was referring to this early dinosaur's hollow bones, an adaptation that helped it to remain nimble and light on its feet in its hostile North American ecosystem.

05
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Coelophysis Was One of the First Dinosaurs With a Wishbone

Not only were Coelophysis' bones hollow, like the bones of modern birds; this early dinosaur also possessed a true furcula, or wishbone. However, late Triassic dinosaurs like Coelophysis was only distantly ancestral to birds; it wasn't until 50 million years later, during the late Jurassic period, that even smaller theropods like Archaeopteryx truly started evolving in an avian direction, sprouting feathers, talons and primitive beaks.

06
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Thousands of Coelophysis Fossils Have Been Discovered at Ghost Ranch

coelophysis
Wikimedia Commmons

For nearly a century after it was discovered, Coelophysis was a relatively obscure dinosaur. That all changed in 1947, when the pioneering fossil hunter Edwin H. Colbert discovered thousands of Coelophysis bones--representing all growth stages, from hatchlings to juveniles to teenagers to adults-- tangled together in New Mexico's Ghost Ranch quarry. That, in case you were wondering, is why Coelophysis is the official state fossil of New Mexico!

07
of 11

Coelophysis Was Once Accused of Cannibalism

coelophysis
Wikimedia Commons

Analysis of the stomach contents of some Ghost Ranch Coelophysis specimens has revealed the fossilized remnants of smaller reptiles--which once prompted speculation that Coelophysis ate its own young. However, it turns out that these tiny meals weren't Coelophysis hatchlings after all, or even the hatchlings of other dinosaurs, but rather small archosaurs of the late Triassic period (which continued to coexist alongside the first dinosaurs for about 20 million years).

08
of 11

Male Coelophysis Were Bigger than Females (or Vice-Versa)

coelophysis
Wikimedia Commons

Because so many specimens of Coelophysis have been discovered, paleontologists have been able to establish the existence of two basic body plans: "gracile" (that is, small and slender) and "robust" (that is, not so small and slender). It's very likely that these corresponded to the males and females of the genus, though it's anyone's guess as to which was which! (In many species of birds--which evolved from theropod dinosaurs--the females are bigger than the males.)

09
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Coelophysis May Have Been the Same Dinosaur as Megapnosaurus

megapnosaurus
Megapnosaurus (Sergey Krasovskiy).

There is still a lot of debate about the proper classification of the early theropods of the Mesozoic Era. Some paleontologists believe that Coelophysis was the same dinosaur as Megapnosaurus ("big dead lizard"), which was itself known as Syntarsus until a few years ago. It's also possible that Coelophysis roamed the expanse of Triassic North America, rather than just being restricted to its southwestern quadrant, and thus may wind up being synonymized with similar theropod dinosaurs from the northeast and southeast.

10
of 11

Coelophysis Had Unusually Large Eyes

coelophysis
Wikimedia Commons

As a general rule, predatory animals rely more on their sense of sight and smell than their relatively slow-witted prey. Like many small theropod dinosaurs of the Mesozoic Era, Coelophysis had unusually well-developed eyesight, which presumably helped it to home in on its prospective meals--and may even be a hint that this dinosaur hunted at night. (Bigger eyes also mean a correspondingly bigger brain, which was necessary to process and coordinate the extra visual information.)

11
of 11

Coelophysis May Have Congregated in Packs

coelophysis
Wikimedia Commons

Whenever paleontologists discover extensive "bone beds" belonging to a single genus of dinosaur (see slide #6), they're tempted to speculate that this dinosaur roamed in massive packs or herds. Today, the weight of opinion is that Coelophysis was indeed a pack animal, but it's also possible that isolated individuals drowned together in the same flash flood, or a series of such floods over years or decades, and wound up being washed into the same location.