Washington: For the first time, scientists have discovered the complete remains of a pivotal ancestor of Earth''s largest land animals – the sauropod dinosaurs, in China.
The new species, tentatively dubbed Yizhousaurus sunae, lived on the flood plains around Lufeng in the Yunnan Province of South China about 200 million years ago.
Unlike its 120-foot-long, 100-ton successos, Yizhousaurus was about 30 feet in length, but does have similar features - the beginning of a long neck, a robust skeleton and four-legged posture.
“Sauropods have these big bones but their skulls are very lightly constructed and also very small,” said palaeontologist Sankar Chatterjee of Texas Tech University.
Yizhousaurus's skull is broad, high and domed, less than a foot long with a short snout, eye sockets on the sides for scanning enemies. It has an unusually wide and U-shaped jaw, in top view.
Numerous serrated and spoon-shaped teeth of the upper and lower jaws would shear and slide past each other for cutting plant material during feeding. The sturdy teeth and raised neck let the animal very easily nip small branches from treetops and then chew the plant material.
“Once the plant food was ingested, a gastric mill in the stomach probably provided further mechanical breakdown of the plant,” Chatterjee explained.
Half a century ago spectacular specimens of prosauropod dinosaurs such as Lufengosaurus were discovered at the same location – which supports the theory that prosauropods gave rise to sauropods, despite the fact that the transition has been very vague, Chatterjee said.