Remains of a colossal, surprisingly bird-like dinosaur have been uncovered in Inner Mongolia, China, scientists say.
The animal, which lived in the Late Cretaceous period, about 70 million years ago, is thought to have weighed about 1,400 kilograms (3,000 pounds). That’s surprising, paleontologists said, because most theories suggest carnivorous dinosaurs got smaller as they evolved to become more bird-like.
The dinosaur, described in this week’s issue of the research journal Nature, has been classed as a new species and genus.
Xing Xu of the Chinese Academy of Sciences in Beijing and colleagues analyzed the skeleton and grouped the fossil with a family that included the beaked, bird-like Oviraptor, because of its similarly avian features. The family is known as Oviraptorosauria.
Artist's reconstruction of Gigantoraptor with much smaller feathered dinosaurs known as ornithomimids. (Courtesy Zhao Chuang and Xing Lida/IVPP)
But what’s most striking, the researchers said, is that the beast was about 35 times heavier than other similar feathered dinosaurs, which rarely exceeded 40 kilograms. Also, the “bizarre” shape of certain bones indicates the animal, dubbed Gigantoraptor erlianensis, was “a highly specialized lineage,” Xu and colleagues wrote.
The authors estimate that the new dinosaur would have been about eight metres (26 feet) long and would have stood, at the shoulder, twice the height of a man. They suggest that a growth rate considerably faster than large North American tyrannosaurs contributed to this. The team also noted lines of arrested growth on the fossil, indicating that it was still a young adult when it died. That suggests the full-sized dinosaur may have been even larger, they argued.
Courtesy Nature and World Science