New Mexico’s official cannibalistic ceratosaur, Coelophysis

Can you name your state fossil? Don’t feel bad if you can’t, as a number of states have yet to identify a species themselves, as with Kentucky’s blanket adoption of brachiopods. Since states aim for a fossil discovered in their borders, states along what was once the Western Interior Sea, and now the Rocky Mountains, have bit of an advantage if you were hoping to feel patriotic about an official dinosaur for your state. Having grown up in New Mexico, it’s not too hard to brag about the state fossil, Coelophysis. Coelophysis (See-loe-fie-sis) was not only a fairly interesting theropod back in the Triassic period, but was also discovered in circumstances that resonate a bit with the humans living in New Mexico today.

Coelophysis was a speedy ceratosaur from around 205 million years ago. It wasn’t the largest predator compared to later headliners like Allosaurus (kudos, Utah), but at nearly 10-feet-long, it was still a formidable hunter with nearly 100 serrated teeth and clawed hands. Coelophysis likely preyed up on small crocodiles, lizards, mammals, and possibly anything small enough to gobble up, as suggested by the cannibalized young that have been found in adult abdomens and more conclusively, coprolites.

Mass death in the desert

There have been relatives of Coelophysis found around the world, with Megapnosaurus possibly being the same animal living in Africa in the Jurassic period, but all the Triassic Coelophysis specimens have come from New Mexico. The largest find was a bone bed with of hundreds of individuals collected from Ghost Ranch, New Mexico, which seemed to have been killed in one large catastrophe. While poisoning or disease has been suggested, the most likely cause of death is some kind of flash flooding. While not a leading cause of death in New Mexico, warnings about flash flooding are common enough, even tying into folklore to warn children away from normally underwhelming rivers in the desert.

Perhaps if Coelophysis had spent some more time teaching their kids about flooding dangers instead of eating them, some of them might have escaped. Then again, that might have left New Mexico with a much duller state fossil, like fusulinids. (Just kidding, the state is bursting with cool fossils, some of which you can even collect yourself.)

Source: Coelophysis by New Mexico Museum of Natural History and Science, New Mexico State Fossil.org