Wednesday 30 October 2013

A new species of Hadrosauroid Dinosaur from the Late Cretaceous of Shanxi Province, China.

Hadrosaurs, or Duck-Billed Dinosaurs, were large herbivorous Ornithischian Dinosaurs widespread across Laurasia (Eurasia plus North America; Laurasia split away from the southern continents in the Triassic, the split into North America and Eurasia during the Cretaceous) during the Late Cretaceous. They were descended from the earlier Iguanadontids, but with more sophisticated jaws and teeth, which allowed them to chew their food, not by side-to-side motion as in a modern mammal, but by a unique flexion of the upper jaw parts, which moved apart as the lower jaw moved upwards (from which scientists conclude these Dinosaurs must have had lips, unlike any modern relative of the Dinosaurs). The term 'Hadrosauroid' refers to the widest possible grouping of Hadrosaurs, including all animals in the group after their evolutionary split with the Iguanadontids in the Early Cretaceous, whereas the most derived members of the group are split into two subgroups, the Lambeosaurs, which had hollow boney crests, thought to have been used for making sounds, and the Saurolophides, which either lacked crests or had solid ones.

In a paper published in the journal PLoS One on 18 October 2013, a team of scientists led by Run-Fu Wang of the Shanxi Museum of Geological and Mineral Science and Technology describe a new species of Hadrosauroid Dinosaur from the Late Cretaceous Zhumapu Formation of Shanxi Province in northern China.

The new species is named Yunganglong datongensis, where 'Yunganglong' refers to the Yungang Grottoes, a group of ancient rock-cut Buddhist temples about 50 km from the site where the specimen was discovered, with the suffix '-long' meaning Dragon, and 'datongensis' refers directly to the site where the specimen was found, in Datong City.

The specimen is described from the caudodorsal part (base) of a skull, two cervical vertebrae, a partial dorsal neural arch and neural processes, two caudal vertebrae, distal portions of both ischia, the distal end of a left femur, proximal portion of a right tibia and the distal portion of a left tibia with astragalus, all presumed to come from the same animal.

The caudodorsal part of the skull of Yunganglong datongensis  (A) Right lateral view. (B) Dorsal view. (C) Caudal view. Scale bar is 10 cm. Wang et al. (2013).

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