Discovery of the bizarre new species, Falcarius utahensis, is reported in the Thursday May 5 issue of the journal Nature by paleontologists from the Utah Geological Survey and the Utah Museum of Natural History at the University of Utah.
Scientists do not yet know if the creature ate meat, plants or both, says James Kirkland, Utah state paleontologist at the Utah Geological Survey and principal scientist for the new study. But "Falcarius shows the beginning of features we associate with plant-eating dinosaurs, including a reduction in size of meat-cutting teeth to leaf-shredding teeth, the expansion of the gut to a size needed to ferment plants, and the early stages of changing the legs so they could carry a bulky body instead of running fast after prey."
The adult dinosaur walked on two legs and was about 13 feet long (4 meters) and stood 4.5 feet tall (1.4 meters). It had sharp, curved, 4-inch-long (10 centimeter) claws. Falcarius, which dates to the Early Cretaceous Period about 125 million years ago, belongs to a group of dinosaurs known as therizinosaurs. The group includes feathered dinosaurs such as Beipiaosaurus that were found in southeast China in recent years. Falcarius and Beipiaosaurus are about the same age and appear to represent an intermediate stage between deadly carnivores and later, plant-eating therizinosaurs. Falcarius is anatomically more primitive than the Chinese therizinosaurs.
The therizinosaurs are maniraptorans. Birds evolved from maniraptorans, a group that includes sharp-clawed meat-eaters such as Utahraptor and Velociraptor, the dinosaur popularized by chasing children through the kitchen in the hit film "Jurassic Park."
Falcarius "is the most p