Field Museum paleontologist leads study on two new dinosaurs ...( During the summers of 2006 and 2007...)

During the summers of 2006 and 2007, an international team of researchers from China and the United States excavated a treasure trove of dinosaur skeletons from Early Cretaceous rocks in the southern part of the Gobi Desert near the ancient Silk Road city of Jiayuguan, Gansu Province, China. Two of their discoveries represent new species of theropod dinosaurs, and both are described in technical publications published on-line in the Proceedings of the Royal Society B this week. The papers will appear in print later this year in a special volume entitled "Recent advances in Chinese palaeontology."

One of the new animals is an early relative of T. rex, and is named Xiongguanlong baimoensis (shong-GWAN-long by-mo-EN-sis). The generic name derives from the ancient Chinese name Xiong Guan ("Grand Pass") for Jiayuguan and long for dragon. The specific name baimoensis comes from "bai-mo," for "white ghost," in reference to a dramatic landform in the field area known as the "white ghost castle."

Xiongguanlong would have stood about five feet tall at the hip and weighed close to 600 pounds. It had a skull over a foot and half in length and armed with over 70 teeth. "Although impressive by today's standards, Xiongguanlong was still a fly weight predator compared to its heavy-weight relatives such as T. rex" says Peter Makovicky, PhD, Curator of Dinosaurs at Chicago's Field Museum, and corresponding author on the study of this animal. The world's largest known T. rex specimen, housed at The Field Museum and popularly known as SUE, was nearly 14 feet tall at the hips and is estimated to have weighed between six and seven tons.

Xiongguanlong represents a "missing link" in the fossil record of tyrannosaur dinosaurs. Large tyrannosaurs that lived near the end of the age of dinosaurs like T. rex and Albertosaurus have been known to science for over a hundred years, and the last decade has witn
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