Tuesday, March 3, 2009

Coelophysis

This small predator was one of the first dinosaurs to walk on dry land. It lived during the Late Triassic (about 225 million years ago), and was so successful that its descendants flourished through the Jurassic "Golden Age" of dinosaurs.

Its name (pronounced SEE-low-fie-sis) means "hollow form", derived from its light, hollow bones, a trait it shares with modern birds. This is without a doubt one of the best known dinosaurs: hundreds of skeletons have been found, including a formation of about a dozen animals killed together in a flash flood near Ghost Ranch, New Mexico, still in their death poses. Some of these skeletons have the bones of juvenile coelophysis in their stomachs, suggesting that these creatures may have been cannibals when food became scarce.

Full grown it was about three meters long, slightly larger than a man, but because of its hollow bones and light frame it weighed only about 60 pounds. The many sharp teeth are ideally suited for eating small prey such as insects or fish, and its clawed hands suggest it could grab small items or scrape the earth for worms and grubs.

In the 1940s, thousands of bones were discovered together at the Ghost Ranch. Several hundred individual animals all have their bones jumbled together, presumably after perishing together in some kind of mass extinction event. Evidence suggests that these kinds of events were common in North america at the time: the continents were still all joined together in one piece, called Pangaea. The interior was, therefore, extremely dry and warm, and thus very prone to flooding when rain did come.

This kind of flooding still takes place in the slot canyons of the southwestern US. Coincidentally, the famous painter Georgia O'Keeffe lived at the Ghost Ranch until her death in 1949.

Coelophysis seems to have been one of the most widespread of the meat-eaters during the late Triassic, although it was not the top predator. Larger prey were left to the crococile-like animals with which it shared the region.
Two different weights of skeletons have been found, suggesting that males and females traveled together. Its fossil remains also showed that it hunted in packs. A close relative, Procompsognathus, became a widely known small pack hunter in Michael Crichton's 1995 novel The Lost World.

In a strange turn of events, the skull of a coelophysis was taken on a launch of the space shuttle Endeavor in 1998. It was transfered to the Russian space station Mir, where it traveled more than 3.7 million miles in orbit around the Earth, making it the first ever dinosaur astronaut. The skull was eventually returned to the Carnegie Museum of Natural History unharmed, where it now remains on display.

There's nothing in the world cooler than dinosaurs. The books National Geographic Dinosaurs, by Paul Barrett, and Dinosaurus, by steve Parker are guaranteed to give character to any coffee table.

For my previous posts on dinosaurs, click here.

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