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)