Mandschurosaurus


Mandschurosaurus is an extinct genus of hadrosaurids based on material from the Late Cretaceous of China and possibly also the Early Cretaceous of Laos. It was the first dinosaur genus named from China.

Discovery and naming

The holotype of M. amurensis, the only valid species within the genus, is based on a poorly preserved and incomplete skeleton collected by Russian scientists in 1914 from the banks of the Amur River, China in a layer of the Maastrichtian-aged Yuliangze Formation and the remains represent a large hadrosaurid. The holotype material was initially referred to the genus Trachodon as T. amurense by Riabinin, but was later reassigned to a new genus by Riabinin.
The holotype of M. laosensis, which is based mainly on an ilium and other fragmentary remains, comes from the Aptian-Albian-aged Grès supérieurs Formation in Laos and was named by Hoffet. A mounted skeleton based on the holotype of M. amurensis is on display at the Central Geological and Prospecting Museum in St. Petersburg, although much of the skeleton is plaster.

Description

While the holotype of M. amurensis would have measured long and tall, the largest specimen would have measured long and tall and weighed around 1.5-2 metric tons.
It had a broad, flat beak and a long tail, similar to related hadrosaurs.

Classification

There has been some debate regarding the validity of this genus. Brett-Surman first considered it a nomen dubium, though some later workers have continued to see it as a valid taxon. Most recently, Horner |Horner] et al. listed the type species as a nomen dubium in the second edition of The Dinosauria.
Over the years, three species have been placed within this genus: Mandschurosaurus amurensis, M. mongoliensis, and M. laosensis. Brett-Surman considered M. mongoliensis a distinct genus, which he named Gilmoreosaurus and Horner et al. considered M. laosensis a nomen dubium; This leaves only Riabinin's original species, M. amurensis, as a possibly valid taxon.
Within Ornithopoda, Mandschurosaurus is most often placed within Hadrosauridae as a nomen dubium.