Yimenosaurus (Yimen lizard)
Z. bai, J. Yang & G. Wang - 1990
Estimated 9 meters long
Y. youngi (type)
China, Yimen - Fengjiahe Formation
Jurassic, 170 million years ago
Yimenosaurus is a genus of herbivorous dinosaur that lived during the Jurassic period, around 170 million years ago. Its fossils were found in the Yimen Formation of Yunnan Province, southern China. Yimenosaurus belongs to the group of sauropod dinosaurs, which are known for their long necks, small heads, and massive bodies.
Yimenosaurus was a medium-sized sauropod, reaching up to 10 meters (33 feet) in length and weighing around 5 metric tons (5.5 short tons). It had a long, slender neck and a small head with a blunt snout, and its teeth were peg-like, suited for grinding tough plant material. Its forelimbs were shorter than its hindlimbs, and all four limbs were supported by hoof-like claws.
One of the most distinctive features of Yimenosaurus is its unique back vertebrae, which are elongated and deeply excavated by a large, concave depression. This feature is also found in a few other sauropod dinosaurs, including Mamenchisaurus and Omeisaurus, and its function is still not well understood.
Yimenosaurus likely lived in herds and spent most of its time browsing on low vegetation, using its long neck to reach high branches. It may have been preyed upon by carnivorous dinosaurs like Yangchuanosaurus, which lived in the same area during the same time period.
The discovery of Yimenosaurus and other dinosaur fossils in southern China has greatly expanded our understanding of the diversity of dinosaurs during the Jurassic period, and has shed new light on the evolution of sauropod dinosaurs.