'Giraffe of the Mesozoic' Discovered

Brachiosaurs were herbivorous dinosaurs belonging to the sauropod family, but in comparison to some brachiosaurs, the new species, Qiaowanlong kangxii, is quite small, at only around 10 feet tall and close to 40 feet long. It weighed a mere 10 tons.

The new brachiosaur specimen was described by authors Hai-Lu You and Da-Qing Li, in a paper published online on 4 September 2009, in the Proceedings of the Royal Society B. The brachiosaur was given the scientific name Qiaowanlong kangxii from Qiao (bridge), wan (bend in a stream), long (dragon), in reference to the area where it was found, and Kangxi, a Qing Dynasty Emperor who is supposed to have dreamt about the scenic Qiaowan region.

The specimen was found in the Yujingzi Basin in Gansu Province in North West China, at an excavation site in which many other dinosaur fossils have been found in recent years, including at least three new species.

Earlier studies into sauropods suggested the animals held their necks straight out, and swung them from side to side, rather like a metal detector, but the Chinese scientists found the brachiosaur skeleton had a similar bifurcated (two-part) spine to those in other sauropods, but not previously found in brachiosaurs.

The bifurcated spine and the structure of the other bones discovered, including a unique pelvis, suggest the neck "should have been held aloft, with a more vertical than horizontal behavior," according to Hai-Lu You. Having long forelimbs and a long neck held aloft, would have made it look a little like today's giraffes, and like them, the brachiosaur would have grazed vegetation high above the reach of its competitors for food.

Sauropods were thought to have been most populous in the Jurassic in Africa and North America, but some paleontologists have theorized their population declined rapidly early in the Cretaceous period. The new finding casts doubt on this theory, since a growing number of Early Cretaceous sauropods is being discovered in China.

Dr Jerry Harris, Dixie State College's Director of Paleontology, who worked with the Chinese scientists, explained that what makes the discovery so important is how it adds to our knowledge about how dinosaur populations could move around the globe in the Early Cretaceous period.

Land bridges between the continents were vanishing at this time, but as the new brachiosaur has similarities to dinosaur remains found in North America, Harris suggests some connections did still exist if only sporadically. The dinosaurs took advantage of the land bridges to move around, which explains why Chinese and American brachiosaurs appear to be closely related.

More information: The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia; Hai-Lu You, Da-Qing Li; Proceedings of the Royal Society B; doi: 10.1098/rspb.2009.1278

© 2009 PhysOrg.com