Coelophysis bauri

In the summer of 1947, paleontologist Edwin Colbert and a team of preparators from The American Museum of Natural History in New York City headed west to work in Arizona's Petrified Forest. On their way, they took a side trip to Ghost Ranch, several thousand acres of private land near Abiquiu, New Mexico, where rock strata from the Late Triassic Period (~215 million years ago) was exposed.

Their field plans changed when the group discovered what would later turn out to be a 30-by-50-foot bone bed containing an unprecedented number of bones of the small, bipedal carnivorous dinosaur, Coelophysis bauri. The remains contain a representative cross-section of the population, from juveniles to full-sized adults.

Each field season lasted up to three months. By the end of the 1948 field season, 13 plaster and burlap covered field jackets weighing hundreds of pounds apiece had been quarried from the soft siltstone. In subsequent years, other expeditions and other institutions removed an additional 17 blocks.

The fossil remains at Ghost Ranch were found in such high concentrations it suggests the animals were killed suddenly in a single cataclysmic event. Against incredible odds—for the chances of any once living creature becoming a fossil are slim—the partial skeletons were preserved in a sudden flow of mud-like silt. And all had been undisturbed for millions of years.

Over the years, the American Museum of Natural History traded blocks from the Ghost Ranch quarry in exchange for other specimens. This is how The Cleveland Museum of Natural History came to possess Block XII in 1969. Department of Vertebrate Paleontology volunteer, Dale Zelinski, spent almost nine years preparing many of the delicate individual bones out of the Museum's block.

Zelinski careful work exposed approximately 32 individual partial Coelophysis skeletons. Eventually a composite mount of Coelophysis, consisting of parts of at least three individuals, went on display in Kirtland Hall of Prehistoric Life in 2001.

Coelophysis

The skeleton of Coelophysis indicates that the animal was an active predator. It had long, slender hind limbs; an extremely long counterbalancing tail; an elongated, pointed head; large eyes; sharp, serrated teeth and fairly long forelimbs, each with three fingers. The largest adults could grow up to 10 feet long and 60 pounds in weight.

Coelophysis may have preyed upon small, fleet-footed herbivorous dinosaurs, as well as lizards and insects.

Work Continues

The exact number of Coelophysis skeletons present within the Ghost Ranch deposit cannot be determined, since only eight of the collected blocks have yet to be prepared. The skeletal remains of at least 200 individuals remain in the quarry itself.