A team of scientists that includes Utah state paleontologist James Kirkland have identified a new dinosaur from a partial skull and other fossil bone fragments recovered in a 91-million-year-old formation in western New Mexico.
Jeyawati rugoculus appears to be a link between the iguanodon lineage and hadrosaurs, a highly evolved group of duck-billed dinosaurs that was abundant in North American during the closing chapters of the dinosaurs' reign, according to findings published this month in the Journal of Vertebrate Paleontology .
Lead author Andrew McDonald, a doctoral student of paleontology at the University of Pennsylvania, believes this plant-eating creature roamed the western shore of what was once an inland seaway that cut North America in half during mid-Cretaceous era. McDonald authored the paper with Kirkland and Doug Wolfe as part of his senior thesis at the University of Nebraska.
The genus names comes from the Zuni word for "grinding mouth," a reference to jeyawati's advanced chewing mechanism, and the species name is Latin for "wrinkle eye." This refers to a rough patch on the bone outside the eye socket, a feature that is apparently unique to this dinosaur. The scientists speculate this patch supported large scales around the eyes.
Kirkland believes another Jeyawati specimen has been found at Utah's Grand Staircase Escalante National Monument, but it's impossible to know for sure because it lacks a skull.
The specimen described in the paper was found in 1996 by paleontologist Doug Wolfe and his family in the Moreno Hills Formation near Red Hill, N.M. Little more was recovered than pieces of jaw and other skull fragments, vertebrates and ribs. It remained at the Arizona Museum of Natural History for several years before Wolfe invited McDonald to study it. The young scientist soon figured these few bones, which had been separated from their matrix by Harold and Phyllis Bolan, belonged to a species new to science.
"I didn't know we had enough of that animal to name it but Andrew went to work on it," Kirkland said.
The specimen was likely a young adult, up to 20 feet in length, and walked on two feet. The three ridges on jeyawati teeth are among the features that suggested the creature is an evolutionary bridge between the various iguanodon species and their duck-billed descendants, McDonald said. Iguanodon teeth bear five ridges, while hadrosaurs have just one.