''Hudiesaurus'' (meaning "butterfly lizard") is a herbivorous

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 bo ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. Its

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

remains were found in 1993 by a Chinese-Japanese expedition near Qiketai in

Shanshan Shanshan (; ug, پىچان, Pichan, Piqan) was a kingdom located at the north-eastern end of the Taklamakan Desert near the great, but now mostly dry, salt lake known as Lop Nur. The kingdom was originally an independent city-state, known in t ...

Xinjiang Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwest ...

province. The genus contains a single species, ''Hudiesaurus sinojapanorum'', was named and described by

Dong Zhiming Dong Zhiming (Chinese: 董枝明, Pinyin: ''Dǒng Zhimíng''; born January 1937) is a Chinese vertebrate paleontologist formerly employed at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. He began working at the ...

in 1997. The generic name is derived from

Mandarin Mandarin or The Mandarin may refer to: Language * Mandarin Chinese, branch of Chinese originally spoken in northern parts of the country ** Standard Chinese or Modern Standard Mandarin, the official language of China ** Taiwanese Mandarin, Stand ...

''hudie'', meaning "butterfly," and refers to a flat butterfly-shaped process on the front base of the vertebral spine. The specific name refers to the members of the Sino-Japan Silk Road Dinosaur Expedition but can also be read as "central part" in Chinese, a pun on the Japanese ''Chunichi Shinbun'' (again "central part") press group, which financed the research.Dong, Z. (1997). "A gigantic sauropod (''Hudiesaurus sinojapanorum'' gen. et sp. nov.) from the Turpan Basin, China." Pp. 102-110 in Dong, Z. (ed.), ''Sino-Japanese Silk Road Dinosaur Expedition''. China Ocean Press, Beijing.

Discovery

''Hudiesaurus'' is known from only two incomplete specimens, uncovered within sediments in the

Turpan Basin The Turpan Depression or Turfan Depression, is a fault-bounded trough located around and south of the city- oasis of Turpan, in the Xinjiang Autonomous Region in far Western China, about southeast of the regional capital Ürümqi. It includes ...

equivalent to the

Kalazha Formation The Kalaza Formation is a geological formation in Xinjiang, China whose strata date back to the Late Jurassic. There is some confusion with the stratigraphy of this unit, as the term is used for sediments of equivalent age in both the Junggar Basin ...

of the

Junggar Basin The Junggar Basin () is one of the largest sedimentary basins in Northwest China. It is located in Xinjiang, and enclosed by the Tarbagatai Mountains of Kazakhstan in the northwest, the Altai Mountains of Mongolia in the northeast, and the Heaven ...

, which perhaps dates to the late

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Period. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

(IVPP V 11120) is represented only by a very large posterior cervical vertebra. A partial skeleton belonging to a smaller individual was found about away from the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

. This specimen, IVPP P. 11121, consisting of a nearly complete right front leg and teeth, was referred to ''Hudiesaurus'' by Dong. In 2004, Paul Upchurch rejected this proposal because of a lack of overlapping material.Upchurch, P.; Barrett, P.M.; Dodson, P.; 2004 "Sauropoda". In: Weishampel, D.B. and Dodson, P. and Osmolska, H., (eds.) ''The Dinosauria''. p 259 - 322. University of California Press: Berkeley and Los Angeles Upchurch ''et al.'' made the specimen the holotype of a new genus, ''

Rhomaleopakhus ''Rhomaleopakhus'' (meaning "strong forearm") is a genus of mamenchisaurid sauropod, dinosaur from the Late Jurassic Kalaza Formation of China. The type and only species is ''Rhomaleopakhus turpanensis''. History The holotype IVPP-V11121-1, was ...

'', in 2021.

Description

Despite the fragmentary nature of the fossil material, ''Hudiesaurus'' is believed to have been very large, even for a sauropod, given the considerable length of the vertebral centrum of . Its body length is estimated at .Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'
Winter 2010 Appendix.
/ref> In 2016,

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...

estimated its length at and its weight at . In 2021, Upchurch ''et al.'' suggested that the

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

may be

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cervic ...

instead of

thoracic The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

'','' suggesting that the animal would be at and .

Classification

In the original description, Dong thought ''Hudiesaurus'' may have been related to ''

Mamenchisaurus ''Mamenchisaurus'' (or spelling pronunciation ) is a genus of sauropod dinosaur known for their remarkably long necks which made up nearly half the total body length. Numerous species have been assigned to the genus; however, many of these might ...

'' and accordingly placed it in the

Mamenchisauridae Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods. Classification T ...

. In 2004, Upchurch limited the precision to a more general

Eusauropoda Eusauropoda (meaning "true sauropods") is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of ''Shunosaurus'', and possibly ''Barapasaur ...

. In the 2021 description of ''Rhomaleopakhus'', the relationships of ''Hudiesaurus'' were again revised. In their phylogenetic analysis, Upchurch ''et al.'' proposed that ''Hudiesaurus'' was a member of the Mamenchisauridae, as a

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to two ''Mamenchisaurus'' species (''M. youngi'' and a referred specimen of ''M. hochuanensis'') and ''Xinjiagtitan'', as well as a clade containing the holotype of ''M. hochuanensis'' and ''Klamelisaurus''. Their cladogram is shown below:

References

External links

"How big was ''Hudiesaurus?''"
''Sauropod Vertebra Picture of the Week'', January 17, 2008 Late Jurassic dinosaurs of Asia Mamenchisaurids Taxa named by Dong Zhiming Fossil taxa described in 1997 Paleontology in Xinjiang {{Sauropodomorph-stub