A team of paleontologists from Japan, China and Canada has described a new genus and species of sauropod dinosaur that lived during the Upper Jurassic epoch, approximately 160 million years ago.

The new dinosaur, named Qijianglong guokr (means Dragon of Qijiang), belongs to Mamenchisauridae, a family of dinosaurs known for their extremely long necks sometimes measuring up to half the length of their bodies.

The neck vertebrae and the head of the dinosaur were found near Qijiang, Chongqing Municipality, southern China.

“It is rare to find a head and neck of a long-necked dinosaur together because the head is so small and easily detached after the animal dies,” said Tetsuto Miyashita, a PhD student at the University of Alberta and a co-author of the paper published in the Journal of Vertebrate Paleontology.

Qijianglong guokr was about 15 meters in length. It had neck vertebrae that were filled with air, making the neck relatively lightweight despite its enormous size.

Interlocking joints between the vertebrae also indicate a surprisingly stiff neck that was much more mobile bending vertically than sideways, similar to a construction crane.

“Qijianglong guokr is a cool animal. If you imagine a big animal that is half-neck, you can see that evolution can do quite extraordinary things,” Miyashita said.

Mamenchisaurids are only found in Asia, but the discovery of Qijianglong guokr reveals that there could be as many differences among mamenchisaurids as there are between long-necked dinosaurs from different continents.

“Qijianglong guokr shows that long-necked dinosaurs diversified in unique ways in Asia during Jurassic times – something very special was going on in that continent. Nowhere else we can find dinosaurs with longer necks than those in China. The new dinosaur tells us that these extreme species thrived in isolation from the rest of the world,” Miyashita said.

“Mamenchisaurids evolved into many different forms when other long-necked dinosaurs went extinct in Asia. It is still a mystery why mamenchisaurids did not migrate to other continents.”

It is possible that the dinosaurs were once isolated as a result of a large barrier such as a sea, and lost in competition with invading species when the land connection was restored later.

The skeleton of Qijianglong guokr is now housed in a local museum in Qijiang.

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Lida Xing et al. A new sauropod dinosaur from the Late Jurassic of China and the diversity, distribution, and relationships of mamenchisaurids. Journal of Vertebrate Paleontology, published online: January 26, 2015; doi: 10.1080/02724634.2014.889701