Yuanmouraptor
Yuanmouraptor is an extinct genus of metriacanthosaurid theropod dinosaurs from the Middle Jurassic Zhanghe Formation of China. The genus contains a single species, Yuanmouraptor jinshajiangensis, known from a partial skull and several consecutive vertebrae.
Discovery and naming
The Yuanmouraptor holotype specimen, LFGT-ZLJ0115, was discovered in March 2006 in outcrops of the Zhanghe Formation on a farm near Xiabanjing Village of Yuanmou County in Chuxiong Yi Autonomous Prefecture, Yunnan Province, China. The specimen consists of a nearly complete skull and mandible, ten articulated, and the first.The name "Yuanmouraptor" was first mentioned in a 2014 newsletter from the Hong Kong Science Museum. As of its 2025 description, the holotype was on display in the Lufeng World Dinosaur Valley Museum.
In 2025, Zou and colleagues described Yuanmouraptor jinshajiangensis as a new genus and species of metriacanthosaurid dinosaurs based on these fossil remains. The generic name, Yuanmouraptor, combines a reference to the discovery of the holotype in Yuanmou County with the Latin word raptor, meaning "robber". The specific name, jinshajiangensis, references the Jinsha River, as the type locality is on the river's north bank.
Description
Yuanmouraptor is described as a "medium-sized" metriacanthosaurid. In all of the holotype vertebrae, the is fused to the respective, with the only somewhat visible on the eighth and ninth cervical vertebrae. As these sutures are open in juvenile animals, the prominent fusion is indicative of a subadult or nearly mature ontogenetic stage for this individual. As preserved, the holotype skull is long. When reconstructed, its full length is around. In comparison, the holotype skull of Yangchuanosaurus shangyouensis is long, belonging to an animal around long.Several autapomorphies of Yuanmouraptor are observable in the and. These include an anterior process of the postorbital that is sheet-shaped with a consistent depth, a ventral ramus of the postorbital with a laterally twisted trough going over the outer surface, strongly posteriorly elongated epipophyses on the anterior cervical vertebrae, and a strongly ventromedially excavated pneumatic foramen on the third cervical vertebra.