''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 th ...

sauropod dinosaur from the

Shengjinkou Formation The Shengjinkou Formation is an Early Cretaceous (Aptian)-aged Konservat-Lagerstätte composed of "interbedded red green and yellow variegated mudstones and siltstones" that is part of the larger Tugulu Group of China.Lucas, Spencer G, Chinese Fos ...

Xinjiang, China 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 ...

. 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 (Kumul) is a prefecture-level city in Eastern Xinjiang, China. It is well known as the home of sweet Hami melons. In early 2016, the former Hami county-level city was merged with Hami Prefecture to form the Hami prefecture-level city with t ...

region of

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 ...

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

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

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

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 lithostrotian titanosaur. Its fossils have been found in Central and Northern Patagonia in South America. Discov ...

'', ''

Kaijutitan ''Kaijutitan'' (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is ''Kaijutitan maui''. Di ...

'', ''

Notocolossus ''Notocolossus'' is a genus of titanosaurian sauropod dinosaur from late Cretaceous strata of Mendoza Province, Argentina. Discovery and naming A fossil of a large sauropod was discovered by the Argentine paleontologist Dr. Bernardo Javier ...

'', 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 stages of the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. U ...

''. 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 fro ...

'' 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

Titanosaurs Early Cretaceous dinosaurs of Asia Cretaceous China Fossil taxa described in 2021 {{sauropodomorph-stub