Oldest Dinosaur

Imagine a monster with the teeth of a shark, the talons of an eagle, the neck of an antelope and the hindquarters of an ostrich. A mythological chimera? Not at all. "I stepped down into this gulch," recounts University of Chicago paleontologist Paul Sereno, "took 25 steps and screamed." Directly ahead, atop a sandstone knoll, lay the full skeleton of a 2-meter-long (about 6 ft.) carnivore. It proved to be the most ancient dinosaur discovered to date.

Last week, at the meeting of the Society of Vertebrate Paleontologists in Austin, Sereno for the first time revealed details of the find, made last year by a joint U.S.-Argentine expedition. The dinosaur was named Herrerasaurus, after Victorino Herrera, the goat farmer who first led scientists to the area in northwestern Argentina where the bones were found. Smaller than Apatosaurus and less fearsome than Tyrannosaurus, this dinosaur flourished 230 million years ago during the unique period when most of the earth's landmasses were gathered into a single supercontinent, now called Pangea. Until the most recent find, only a smattering of Herrerasaurus bones had been unearthed. Now scientists will be able to look over the complete skeleton for important evolutionary clues. While Herrerasaurus is not the long sought common ancestor of all dinosaurs, notes Sereno, "it's close -- and maybe it's as close as we will ever get."