''Huanghetitan'' (meaning "

Yellow River The Yellow River or Huang He (Chinese: , Mandarin: ''Huáng hé'' ) is the second-longest river in China, after the Yangtze River, and the sixth-longest river system in the world at the estimated length of . Originating in the Bayan ...

titan"), is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the early

Cretaceous Period The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

. It was a basal

titanosauriform Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (henc ...

which lived in what is now Gansu, China.

History

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

, ''Huanghetitan liujiaxiaensis'', was described by You ''et al.'' in 2006. It is known from fragmentary materials including two caudal vertebrae, an almost complete

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

, rib fragments, and the left shoulder girdle, and was discovered in the eastern part of the Lanzhou Basin (

Hekou Group The Hekou Group is a geological group in Gansu Province, China. It is Early Cretaceous in age. Dinosaur body fossils have also been recovered from the Hekou Group, including the iguanodont ''Lanzhousaurus'' and the titanosaurs '' Daxiatitan'', '' ...

) in the Gansu Province in 2004. A second species, ''H. ruyangensis'', was described in 2007 from the Aptian-Albian Haoling Formation of Ruyang County, China (

Henan Province Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...

). A recent cladistic analysis has found that this species is unlikely to be closely related to ''H. liujiaxiaensis'' and requires a new genus name.

Description

''H. liujiaxiaensis'' is a relatively small sauropod, measuring long and weighing . ''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. 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. 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). In 2007, Lü Junchang ''et al.'' created a new

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

for ''Huanghetitan'', the Huangetitanidae, but this family found to be

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

by Mannion ''et al.'' The following is a cladogram from Averianov ''et al.'', 2017, based on the work of Mannion ''et al.'', showing ''Huanghetitan'' as a paraphyletic genus with "''H.''" ''ruyangensis'' being closer to Titanosauria:

References

External links

Dinosaur Mailing List entry which announces the discovery

Mounted skeleton of the type species ''Huanghetitan liujiaxiaensis''

Shoulder and hip material from ''Huanghetitan liujiaxiaensis''

New mounted skeleton of the second and larger species, ''Huanghetitan ruyangensis''
Titanosaurs Albian life Aptian life Early Cretaceous dinosaurs of Asia Cretaceous China Fossils of China Paleontology in Gansu Fossil taxa described in 2006 {{Sauropodomorph-stub