Sinraptor

Discovery

The holotype specimen of Sinraptor was uncovered from the Shishugou Formation during a joint Chinese/Canadian expedition to the northwestern Chinese desert in 1987, and described by Philip J. Currie and Zhao Xijin in 1994. Standing nearly 3 meters (9.8 feet) tall and measuring roughly 7.6 meters (25 feet) in length, two species of Sinraptor have been named. S. dongi, the type species, was described by Currie and Zhao in 1994. A second species, originally named Yangchuanosaurus hepingensis by Gao in 1992, may actually represent a second species of Sinraptor. Whether or not this is the case, Sinraptor and Yangchuanosaurus were close relatives, and are classified together in the family Metriacanthosauridae. Gregory S. Paul proposed that S. dongi would reach 8 metres (26 ft) in length and 1.3 metric tons (1.4 short tons) in body mass, while Holtz estimated it to be 8.8 metres (29 ft) in length.

The dentition of Sinraptor was very similar to that of Allosaurus and indicated that it likely would have preyed upon medium-sized dinosaurs such as stegosaurs by using its blade-like teeth to inflict massive, fatal wounds.

Sinraptor hepingensis, formerly referred to Yangchuanosaurus, is a second species referred to this genus. However, the identity of this species within Sinraptor is questioned by other paleontologists, and the describers of Alpkarakush included this species within Yangchuanosaurus based on their phylogenetic analysis in 2024.