God tests our faith again with more evidence for evolution

Carnivorous dinosaurs turned to veggies

LONDON - A graveyard of feathery dinosaurs in Utah shows signs of carnivores adapting to a more leafy diet, paleontologists say.

The recently discovered species of dinosaurs, called Falcarius utahensis, had legs built for speed like meat-eaters but it also had a wide pelvis designed for the longer gut common in vegetarian animals that ferment plants.

Artist's conception of bird-like feathered dinosaur. (Copyright: Mike Skrepnick)

The creature was 1.4 metres tall and about four metres long from nose to tail. It walked on two legs about 125 million years ago, as flowering plants were evolving.

Falcarius had wooly, feather-like hairs, sharp, curved claws and teeth suited for shredding leaves, rather than cutting apart meat. Scientists don't yet know whether it ever had a hankering for flesh.

Paleontologist James Kirkland of the Utah Geological Survey and his colleagues unearthed the mass graveyard of 2,000 bones at the Cedar Mountain formation south of Green River.

The find helps researchers to fill in gaps in their understanding of plant-eating Therizinosaurs that evolved from meat-eaters.

Therizinosaur (pronounced THAY-rih-ZY-no-sores) were mainly found in Asia, but their fossils are scarce. It's thought they evolved from two-legged predators called theropods, but their closest cousins were raptors like the Velociraptors of Jurassic Park fame.

Falcarius and Velociraptors shared a common, yet-undiscovered ancestor, said study co-author Scott Sampson, a paleontologist and curator at the Utah Museum of Natural History.

Sculpture of Falcarius utahensis. (PaleoForms LLC, Provo, Utah)

"With Falcarius, we have actual fossil evidence of a major dietary shift, certainly the best example documented among dinosaurs," Sampson said in a release. "This little beast is a missing link between small-bodied predatory dinosaurs and the highly specialized and bizarre plant-eating therizinosaurs."

No one knows what killed off the buried dinosaurs, but scientists say drought, volcanic eruptions, fire and botulism poisoning are all possibilities.

The find is described in the May 5 issue of the journal Nature.