''Hamititan'' (meaning "Hami giant") is a genus of

titanosaur Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thr ...

sauropod dinosaur from the

Shengjinkou Formation The Shengjinkou Formation is an Early Cretaceous-aged Konservat-Lagerstätte composed of "interbedded red green and yellow variegated mudstones and siltstones" that is part of the larger Tugulu Group of China. Dinosaur and pterosaur remains have ...

Xinjiang Xinjiang,; , SASM/GNC romanization, SASM/GNC: Chinese postal romanization, previously romanized as Sinkiang, officially the Xinjiang Uygur Autonomous Region (XUAR), is an Autonomous regions of China, autonomous region of the China, People' ...

, China. It contains one species, the type species, ''Hamititan xinjiangensis''.

Discovery and naming

In 2006, a Konservat-Lagerstätte was reported from the

in the

Hami Hami ( zh, c=哈密) or Kumul () is a prefecture-level city in eastern Xinjiang, China. It is well known for sweet Hami melons. In early 2016, the former Hami county-level city merged with Hami Prefecture to form the Hami prefecture-level city ...

region of

, China. This consisted of lake sediments allowing for exceptional preservation of fossils. The same year,

Qiu Zhanxiang Qiu may refer to: *Qiū (surname), Chinese surnames written 丘, 邱, or 秋 *Qiú (surname), Chinese surnames written 仇 or 裘 * Qiu County, in Hebei, China *Kǒng Qiū (), better known as Confucius Confucius (; pinyin: ; ; ), born Kong Q ...

and Wang Banyue started official excavations. Among the excavated fossils were seven caudal vertebrae with three chevrons preserved. These were established as the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

(HM V22) of the new sauropod taxon, ''Hamititan''. Four sacral elements, specimen IVPP V27875, were not referred. A

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

tooth was found near the sixth caudal vertebra of the holotype. It is likely that this theropod preyed on the holotype shortly after it died. The generic name refers to the city of Hami, where the holotype was found, while the specific name, ''xinjiangensis,'' refers to the Chinese province,

Classification

The phylogenetic analysis of Wang et al. places ''Hamititan'' as a derived non-lithostrotian titanosaur in a polytomy with ''

Epachthosaurus ''Epachthosaurus'' (meaning "heavy lizard") was a genus of titanosaurian sauropod dinosaur from the Late Cretaceous. It was a basal Lithostrotia, lithostrotian titanosaur. Its fossils have been found in Central and Northern Patagonia in South Ame ...

'', '' Kaijutitan'', '' Notocolossus'', rinconsaurs, lognkosaurs, and

lithostrotians Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch ''et al.'' in 2004 as the most recent common ancestor of ''Malawisaurus'' and ''Saltasaurus'' an ...

. If it is scored with the contemporary '' Silutitan'' as a single taxon, the combined taxon will be sister to ''

Euhelopus ''Euhelopus'' is a genus of sauropod dinosaur that lived between 145 and 133 million years ago during the Berriasian and Valanginian ages of the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. Lik ...

''. A cladogram depicting the former hypothesis is shown below:

Paleobiology

Other animals from the holotype locality include the pterosaur ''

Hamipterus ''Hamipterus'' is an extinct genus of pteranodontoid pterosaurs from the Early Cretaceous Shengjinkou Formation of northwestern China. It is known from a single species, the type species, ''H. tianshanensis''. Discovery and naming In 2006 from ...

'' and contemporary euhelopodid '' Silutitan'', which is described in the same paper. Together, ''Hamititan'', the aforementioned fauna and an unnamed theropod represent the known vertebrate taxa of the area.

References

{{Sauropodomorpha, T. Titanosauria Dinosaur genera Valanginian dinosaurs Taxa named by Alexander Kellner Fossil taxa described in 2021 Dinosaurs of China