Two PhD students have discovered a new species of dromaeosaurid theropod from the Upper Cretaceous period Wulansuhai formation of Bayan Mandahu, in the Mongol Autonomous Region of China (commonly called Inner Mongolia). The specimen is the first nearly complete theropod dinosaur found in the region since 1972.
Named Linheraptor exquisitus, it was discovered protruding from a cliff during field work conducted in 2008, by Michael Pittman of University College London (UCL) and Jonah Choiniere of George Washington University (GWU). Their research was published online March 19, in the journal Zootaxa.
The specimen is the fifth dromaeosaurid taxon from the Upper Cretaceous Djadokhta formation and its laterally equivalent strata, which includes the Wulansuhai Formation. According to the published paper, “Linheraptor exquisitus closely resembles the recently reported Tsaagan mangas,” with features that “suggest a sister-taxon relationship” between the two. The scientists go on to postulate that this “indicates the presence of a unique dromaeosaurid lineage in the Late Cretaceous of Asia”.
They indicate that the various features of Linheraptor exquisitus and Tsaagan mangas indicate that they both likely represent intermediate species “between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus important for understanding the evolution of some salient features seen in the derived dromaeosaurids.”
The dromaeosauridae family were carnivorous theropod dinosaurs that lived during the Cretaceous period. They included such groups as Linheraptor and Velociraptor, While the Theropod lineage of dinosaurs as a whole included the massive Tyrannosaurus rex and ancestors of modern birds.
The specimen was extremely well preserved. In life, the animal would have been approximately 2.5 meters long and weighed 25 kilograms. As part of the Linheraptor genus, it likely was a fast and agile predator that preyed on small dinosaurs.
In an interview conducted by UCL for the publication of the paper, Michael Pittman discussed the discovery. “Jonah saw a claw protruding from the cliff face,” Pittman said. “He carefully removed it and handed it to me. We went through its features silently but he wanted my identification first. I told him it was from a carnivorous dinosaur and when he agreed I’m surprised nobody in London heard us shouting.
“I’ve always wanted to discover a dinosaur since I was a kid, and I’ve never given up on the idea,” he noted. “It was amazing that my first discovery was from a Velociraptor relative. My thesis is on the evolution and biomechanics of dinosaur tails but the carnivorous dinosaurs are my favorite and my specialty”
The principal researcher on the project was Xing Xu of the Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology & Paleoanthropology (IVPP), of the Chinese Academy of Sciences, Beijing, China. Others participating in the work include Qingwei Tan and Lin Tan of Long Hao Institute of Geology and Paleontology, Hohhot, Nei Mongol China; Dong Xiao and Zhiquan Li of the Department of Land and Resources, Linhe, Nei Mongol, China; James M. Clark of the Department of Biological Sciences, George Washington University, Washington, DC, USA; Mark A. Norell of the Division of Paleontology, American Museum of Natural History, New York City, NY, USA; and David W. E. Hone and Corwin Sullivan both also of the Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology & Paleoanthropology, of the Chinese Academy of Sciences, Beijing, China.
The research was conducted as part of the Inner Mongolia Research Project, led by Dr. Xu. This project seeks to better understand the Late Cretaceous ecosystem of Inner Mongolia, China, which is analogous but less well-studied than the Late Cretaceous ecosystem of Outer Mongolia. The research was funded by the Geological Society of London, the US National Science Foundation, the Chinese National Science Foundation, and George Washington University.
“This is a really beautiful fossil and it documents a transitional stage in dromaeosaurid evolution,” said Dr. Xu Xing in an interview.