The type species, Huanghetitan liujiaxiaensis, was described by You et al. in 2006. It is known from fragmentary materials including two caudal vertebrae, an almost complete sacrum, rib fragments, and the left shoulder girdle, and was discovered in the eastern part of the Lanzhou Basin (Hekou Group) in the Gansu Province in 2004.[1]
A second species, H. ruyangensis, was described in 2007 from the Aptian-Albian Haoling Formation of Ruyang County, China (Henan Province). A recent cladistic analysis has found that this species is unlikely to be closely related to H. liujiaxiaensis and requires a new genus name.[2]
Description
H. liujiaxiaensis is a relatively small sauropod, measuring 12 metres (39 ft) long and weighing 3 metric tons (3.3 short tons).[3]H. ruyangensis is known from a partial vertebral column and several ribs, the size of which (the largest approaches 3 m (10 ft)) indicate it had among the deepest body cavities of any known dinosaur.[4] This second species, along with its local relatives Daxiatitan and Ruyangosaurus, is one of the biggest dinosaurs ever found in Asia, and possibly one of the largest in the world.[5] In 2019 Gregory S. Paul suggested that the dorsal rib of Huanghetitan ruyangensis is about the same length as Patagotitan's, and its sacrum may be similar in length, possibly suggesting a similar mass range of 45–55 tonnes (49.6–60.6 short tons).[6]
In 2007, Lü Junchanget al. created a new family for Huanghetitan, the Huangetitanidae, but this family found to be polyphyletic by Mannion et al.[4][2]
The following is a cladogram from Averianov et al., 2017,[7] based on the work of Mannion et al., showing Huanghetitan as a paraphyletic genus with "H." ruyangensis being closer to Titanosauria:
^You, H.; Li, D.; Zhou, L. & Ji, Q. (2006). "Huanghetitan liujiaxiaensis, a New Sauropod Dinosaur from the Lower Cretaceous Hekou Group of Lanzhou Basin, Gansu Province, China". Geological Review. 52 (5): 668–674.
^Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs 2nd Edition. New Jersey: Princeton University Press. p. 222.
^ abLu J., Xu; L., Zhang; X., Hu; W., Wu; Y., Jia, S. & Ji, Q. (2007). "A New Gigantic Sauropod Dinosaur with the Deepest Known Body Cavity from the Cretaceous of Asia". Acta Geologica Sinica. 81 (2): 167. doi:10.1111/j.1755-6724.2007.tb00941.x. S2CID128462121.((cite journal)): CS1 maint: multiple names: authors list (link)
^Averianov, A.; Ivanstov, S.; Skutschas, P.; Faingertz, A.; Leschinskiy, S. (2018). "A new sauropod dinosaur from the Lower Cretaceous Ilek Formation, Western Siberia, Russia". Geobios. 51: 1–14. doi:10.1016/J.GEOBIOS.2017.12.004.
