Qianzhousaurus (meaning "Qianzhou lizard") is a genus of tyrannosaurid dinosaur that lived in Asia during the Maastrichtian age of the Late Cretaceous period. There is currently only one species named, the type species Qianzhousaurus sinensis, which is a member of the tribe Alioramini and most closely related to Alioramus, the only other known alioramin.
The holotype specimen, GM F10004, was unearthed in southern China, Ganzhou, at the Nanxiong Formation in the summer of 2010 during the construction of an industrial park and it was first described by paleontologists Junchang Lü, Laiping Yi, Stephen L. Brusatte, Ling Yang, Hua Li and Liu Chen in the journal Nature Communications in 2014. The genus is known from a partial sub-adult individual consisting of a nearly complete skull with the lower jaws missing all teeth (lost during fossilization), 9 cervical vertebrae, 3 dorsal vertebrae, 18 caudal vertebrae, both scapulocoracoids, partial ilia, and the left leg compromising the femur, tibia, fibula, astragalus with calcaneum, and metatarsals III and IV. The generic name, Qianzhousaurus, is in reference to Qianzhou (the older name of Ganzhou) where the remains were discovered, and the specific name, sinensis, is derived from the Greek word Σῖναι (sin, sino, sinai) in reference to China.[1] The fossil remains were discovered by workmen at a construction site near the city of Ganzhou, who then took them to a local museum.[2]
Lead author Lü Junchang from the Institute of Geology, Chinese Academy of Geological Sciences stated that "the new discovery is very important. Along with Alioramus from Mongolia, it shows that the long-snouted tyrannosaurids were widely distributed in Asia. Although we are only starting to learn about them, the long-snouted tyrannosaurs were apparently one of the main groups of predatory dinosaurs in Asia."[3] The existence of long-snouted tyrannosaurs was previously suspected due to other inconclusive fossil finds which could be explained as the juveniles of short-snouted species, but co-author Stephen L. Brusatte from the University of Edinburgh reveals that the find "tells us pretty unequivocally that these long-snouted tyrannosaurs were a real thing. They were a different breed, living right at the end of the age of dinosaurs."[4]
Qianzhousaurus was a medium-sized tyrannosaurid estimated at 6.3 m (20.7 ft) in length, 2 m (6.6 ft) in hip height and 750–757 kg (1,653–1,669 lb) in body mass.[1][5] Higher estimates suggest that it could have reached a maximum length between 7.5 and 9 metres (25 and 30 ft).[6] The taxon can be differentiated from other tyrannosaurids in having a highly narrowed premaxilla, a pneumatic opening on the upper extension of the maxilla, and the lack of a vertical ridge-like structure on the lateral surface of the ilium.[1]
Unlike more "traditional" tyrannosaurids, which had prominent deep-set jaws and thick teeth, Qianzhousaurus had a particularly elongated snout, with (when restored) narrow teeth. The holotype specimen is notably larger and more mature than the holotypes of both species of Alioramus. However, since some sutures between the cervical and dorsal vertebrae are partially fused, the holotype seems to have come from an immature animal, likely a sub-adult. Qianzhousaurus was a long-legged animal with a 70 cm (28 in) long femur and 76 cm (30 in) long tibia.[1]