Chinese scientists have discovered a fossilized dinosaur-eating mammal in northeast China's Liaoning Province, according to a report published in this week's edition of the British science journal, Nature.
Hu Yaoming, Wang Yuanqing and Li Chuankui, all from the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology, and Meng Jin from the American Museum of Natural History in New York, actually made two startling discoveries that cast serious doubt on the long-held belief that all mammals of the Mesozoic era -- more than 65 million years ago -- were smaller than the reptiles with whom they shared the planet.
In a specimen of Repenomamus robustus found at the site, they discovered the bones of a juvenile Psittacosaurus in precisely the location where its stomach would have been. From wear marks on the dinosaur's teeth, the researchers inferred that it was not an embryo. The scientists estimate that the dinosaur was just under 13 centimeters long, about one-third the size of the mammal.
The bones, with some joints still intact, indicate that the mammal gobbled its prey in large chunks with very little chewing, according to Li.
The fact that its teeth are all sharp is further evidence of its method of dining: R. robustus lacked molars, which are used for grinding food.
At the same site, researchers also discovered the fossilized remains of a new species, which they have determined to be a cousin of R. robustus. The newly discovered Repenomamus giganticus, as the animal has been dubbed, was more than a meter long, about twice the size of its relative.
Hu Yaoming stated that the animal, which lived some 130 million years ago, probably resembled today's badgers.
(China.org.cn, Xinhua News Agency January 14, 2005)
