| Qijianglong | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Family: | †Mamenchisauridae |
| Genus: | †Qijianglong Xing et al.,2015 |
| Type species | |
| †Qijianglong guokr Xing et al., 2015 | |
Qijianglong is a genus of herbivorousmamenchisauridsauropod dinosaurs. It is known from theSuining Formation of China, which is of a debated age (reported asLate Jurassic orEarly Cretaceous using different methods). The genus contains asingle species,Qijianglong guokr, known from a partial skeleton including cranial bones, most of the neck and tail, and other associated elements.
Avertebra ofQijianglong was first discovered in the early 1990s by farmer Cai Changming of Heba village,Sichuan, in his backyard. Work at a nearby construction site atQijiang District uncovered a rich fossil quarry in 2006. Its excavation caused an examination of the earlier find which led to the discovery of a skeleton. In 2015, thetype speciesQijianglong guokr was named and described byXing Lida (China University of Geosciences),Tetsuto Miyashita (University of Alberta),Zhang Jianping,Li Daqing,Ye Yong (Zigong Dinosaur Museum),Toru Sekiya (Fukui Prefectural Dinosaur Museum),Wang Fengping andPhilip John Currie. The generic name combines the districtQijiang withMandarinlong, "dragon". Thespecific nameguokr, "nutshell", is that of a Chinese scientificsocial network.[2]
Theholotype specimen, QJGPM 1001, was found in a layer of theSuining Formation. The age of this formation is debated, with various methods supporting either a Late Jurassic or Early Cretaceous age.[1][3] The specimen consists of a partial skeleton including the rear of the skull, a partial right lower jaw, a complete series of seventeen neck vertebrae, the first six back vertebrae, ribs, the probable tenth tail vertebra, a series of twenty-eight rear tail vertebrae, chevrons, the left pubic bone and two upper pedal phalanges. It likely represents a juvenile individual, large but immature.[2]
The holotype ofQijianglong was about fifteen meters long and had a long neck. The describing authors established several distinguishing traits among which fourautapomorphies. On the lower braincase theprocessus basipterygoideus has the form of a plate, is oriented along the body axis, and has an additional boss parallel to thetubera basilaria. The neck vertebrae have rear joint processes,postzygapophyses that next to their normal facets show on the outside an additional finger-shaped extension, stiffening the neck in the horizontal plane but allowing vertical movement. The rear neck vertebrae have pneumatopores, pneumatic openings, in the depression between thediapophysis, the upper rib joint process, and the neural spine. Thepubic bone has a concave front edge, curving so strongly that its lower end is more directed to the front than to below.[2]
Qijianglong was placed in thefamilyMamenchisauridae, in a relatively basal position but aboveOmeisaurus tianfuensis in the evolutionary tree.[2]
