Sinraptor: Beast of the Week

Sinraptor was a large meat-eating dinosaur that lived in what is now Northwestern China during the late Jurassic period, about 160 million years ago.  From snout to tail it is estimated to have measured 29 feet (7.6) meters, although some suggest it may have been able to grow longer.  The genus name translates to "Chinese Thief".

Sinraptor belonged to the family of theropod dinosaurs called the metriacanthosaurids, which are relatively closely related to popular dinosaurs, like Allosaurus and Giganotosaurus.  Metriacanthosaurids were relatively large meat-eaters that reigned between the middle Jurassic to the early Cretaceous periods in the northern hemisphere.   Metriacanthosaurus, which has also been reviewed on this site, another member of this family, and close relative of Sinraptor.

Sinraptor dongi chasing a pack of the early tyrannosauroid, Guanlong, off of a kill.

Sinraptor had a relatively deep laterally compressed skull that had jaws lined with long, blade-like teeth.  This seems to have been an adaptation for slashing large chunks of flesh from the bodies of other animals. It had short, powerful arms, that ended in three fingers tipped with hook-shaped claws, which also may have aided in feeding or hunting.  Sinraptor also possessed bony ridges over its eyes and snout which probably had horny keratin growing from it in life.  This was likely an adaptation for communicating with, or perhaps even fighting, members of its owns species.

Sinraptor skull on display at the Zigong Dinosaur Museum, in Sichuan, China. (Photo credit: Zhangshugang)

Sinraptor was likely the top predator of its community, and may have used its size and formidable weaponry to hunt large sauropods and stegosaurs it shared its habitat with.  It also coexisted with the much smaller early tyrannosauroid, Guanlong, which probably avoided Sinraptor wherever possible.

References

Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 10 (2): 211–300.

Currie, Phillip J.; Zhao, Xi-Jin (1993). "A new carnosaur (Dinosauria, Theropoda) from the Jurassic of Xinjiang, People's Republic of China". Canadian Journal of Earth Sciences. 30 (10): 2037–2081.