University of California-Berkeley researchers say complete skeletons prove that Revueltosaurus callenderi was a relative of crocodiles -- not dinosaurs.
Researchers last summer and again this month found two complete skeletons of the creature, named by Adrian Hunt in 1989 based only on teeth found in Revuelto Creek, N.M.
"Because the teeth look like those we know from herbivorous ornithischians, people assigned them to the dinosaurs," said researcher and graduate student Randall Irmis. "We think we've shown that you can't rely on the dentition to determine what is an early dinosaur."
Putting Revueltosaurus into the crocodile category now casts doubt on other presumed dinosaur ancestors known only by their teeth, which includes all ornithischians outside South America from the Late Triassic period 210 million years ago.
The find suggests that, rather than rising together, meat-eating theropods such as Tyrannosaurus rex existed long before the plant-eating ornithischians, researchers said in the journal Proceedings of the Royal Society, Biological Sciences.
Copyright 2005 by United Press International
Explore further: Freedom and responsibility of science