Its remains were found in a bonebed in the middle Maastrichtian-age Yuliangze Formation, dated to 69 million years ago.[1][2][3] This bonebed is otherwise dominated by fossils of the lambeosaurine hadrosaurid (hollow-crested duckbill) Sahaliyania. Wulagasaurus was named by Pascal Godefroit and colleagues in 2008. Only partial remains are known at this time. It is one of several hadrosaurids from the Amur River region named since 2000. The type and only species to date is W. dongi, named in honor of Chinese paleontologist Dong Zhiming.[4]
Wulagasaurus is based on GMH W184, a partial dentary (toothbearing bone of the lower jaw). Godefroit and colleagues assigned additional remains from the bonebed to their new genus, including three braincases, a cheekbone, two maxillae (the toothbearing bone of the upper jaw), another dentary, two shoulder blades, two sternal elements, two upper arm bones, and an ischium. It can be distinguished from other hadrosaurids by its slender dentary and the unique form of its upper arm, which had distinctive articulations and placements for muscle attachments. Godefroit and colleagues performed a phylogenetic analysis that suggests Wulagasaurus was the most basal saurolophine known (which would result in a long ghost lineage[5]), and interpreted this as evidence that saurolophines and hadrosaurids in general originated in Asia, which has been supported by other finds since.[4]
In 2010 Gregory S. Paul estimated its size at 9 meters (30 ft) and 3 tonnes (3.3 short tons).[6] As a hadrosaurid, Wulagasaurus would have been an herbivore.[7]
^Godefroit, P., Lauters, P., Van Itterbeeck, J., Bolotsky, Y. and Bolotsky, I.Y. (2011). "Recent advances on study of hadrosaurid dinosaurs in Heilongjiang (Amur) River area between China and Russia." Global Geology, 2011(3).
^Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. New Jersey: Princeton University Press. pp. 296–297.
^Horner, John R.; Weishampel, David B.; Forster, Catherine A (2004). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 438–463. ISBN0-520-24209-2.
