Monolophosaurus

Monolophosaurus (/ˌmɒnɵˌlɒfəˈsɔrəs/ MON-o-LOF-ə-SAWR-əs;[2] meaning "single-crested lizard") was a genus of theropod dinosaur from the Middle Jurassic Shishugou Formation in what is now Xinjiang, China.[3][4] It was named for the single crest on top of its skull. The type and only known individual is estimated at 5 metres (16.5 ft).[4] The area that Monolophosaurus was found showed signs of water, so it is possible that this dinosaur lived on the shore of lakes or ocean.[citation needed] The Monolophosaurus jiangi IVP 84019 had its 10th and possibly 11th neural spines fractured. The tenth is fused to the eleventh. A series of parallel ridges on one of the specimen's dentaries may represent tooth marks.

Discovery and classification
A nearly complete skeleton was unearthed in 1984. At first, before description in the scientific literature, it was known in the press as "Jiangjunmiaosaurus", a nomen nudum.[3][6]

In 1993 Zhao and Currie named the type species Monolophosaurus jiangi; the species name refers to Jiangjunmiao ("an abandoned desert inn") near which the holotype IVPP 84019 was found.[3][7] Monolophosaurus was originally termed a "megalosaur" and has often since been suggested to be an allosauroid. Carr (2006) even suggested that the "proceratosaurid" "tyrannosauroid" Guanlong was a subadult Monolophosaurus and therefore an "allosauroid",[8] by noting both taxa have a large, thin, and fenestrated midline crest, but this is probably not the case.

Smith et al. (2007) was the first publication to find Monolophosaurus to be a non-neotetanuran tetanuran,[9] by noting many characters previously thought to be exclusive of Allosauroidea to have a more wider distribution. Also, Zhao et al. (2009) noted various primitive features of the skeleton suggesting that Monolophosaurus could be one of the most basal tetanuran dinosaurs instead.[10] Benson (2008, 2010) placed Monolophosaurus in a clade with Chuandongocoelurus that is more basal than Megalosauridae and Spinosauridae in the Megalosauroidea.[1][11] Latter, Benson et al. (2010) found the Chuandongocoelurus/Monolophosaurus clade to be outside of Megalosauroidea and Neotetanurae, near the base of Tetanurae.