During an expedition to Xinjiang, China, an international research team discovered a completely new kind of dinosaur along with a second new intermediate species. Xiyunykus pengi and Bannykus wulatensis are Alvarezaurs, an enigmatic group of dinosaurs that share many features of birds. They have slender bodies with a bird-like skull that contains many small teeth – a contrast to the usual large, sharp incisors of their carnivorous relatives.
" When we described the first known Alvarezaurus, Mononykus, in 1
Early members of the alvarezsaurs group had relatively long arms with clawed hands and larger carnivorous teeth. Over time, the group evolved into dinosaurs that had molehill arms with a single claw. This new discovery of hitherto unknown samples gives researchers an insight into the interim period in which this shift of specialized traits took place.
" It may be difficult to determine the relationships of highly specialized animals, but fossil species with transitional properties, such as xiyunykus and bannykus are enormously helpful because they are bizarre anatomical Characteristics combine with more typical ones, "explains Jonah Choiniere, associate professor at . Wits University and member of the research team
These fossils were discovered during an expedition led by dr. Clark and Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences . The partnership between GW and the Academy has now led to the discovery of nine dinosaur species. "Our international field teams have been enormously productive over the years," says Dr. Xu. "This research shows just a few of our incredible discoveries."
by Connor Ertz Earth.com Staff Writer
Credit: James Clark  Topics: James Clark, Dinosaur