''Tangvayosaurus'' (meaning "Tang Vay lizard") 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 nom ...

of sauropod

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 Aptian-

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0 ...

age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...

Gres superieurs Formation of Savannakhet Province, Laos. It was a basal somphospondylan, about 15 m long, and is known from the remains of two or three individuals.

Description

It is based on TV4-1 to TV4-36, consisting of a partial pelvis, several back

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 characteristi ...

e and a tail vertebra, ribs, and an upper arm bone ( humerus). Another skeleton includes 38 tail vertebrae, a neck vertebra, and most of a hind limb. 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 specime ...

, ''Tangvayosaurus hoffeti'', was described by a group of a dozen scientists led by Ronan Allain in 1999 and the species name honours French palaeontologist

Joshua Hoffet Joshua () or Yehoshua ( ''Yəhōšuaʿ'', Tiberian: ''Yŏhōšuaʿ,'' lit. 'Yahweh is salvation') ''Yēšūaʿ''; syr, ܝܫܘܥ ܒܪ ܢܘܢ ''Yəšūʿ bar Nōn''; el, Ἰησοῦς, ar , يُوشَعُ ٱبْنُ نُونٍ '' Yūšaʿ ...

(1901-disappeared 1945). Allain ''et al.'' also referred the old species ''"

Titanosaurus ''Titanosaurus'' (; ) is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877.R. Lydekker. (1877). Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. ''Records of the Geological Survey of I ...

" falloti'' (Hoffet, 1942),J.-H. Hoffet. (1942). Description de quelques ossements de Titanosauriens du Sénonien du Bas-Laos escription of some titanosaurian bones from the Senonian of Lower Laos ''Comptes Rendus des Séances du Conseil des Recherches Scientifiques de l'Indochine'' 1942(1):49-57 from the same formation and based on partial thigh bones and tail vertebrae, to their genus as ''T. sp.'' The most recent review tentatively retains the genus because it is different from the only other established sauropod from the same approximate time but found next door in Thailand (''

Phuwiangosaurus ''Phuwiangosaurus'' (meaning "Phu Wiang lizard") is a genus of titanosaur dinosaur from the Early Cretaceous (Valanginian-Hauterivian) Sao Khua Formation of Thailand. The type species, ''P. sirindhornae'', was described by Martin, Buffetaut, and ...

''), but disagrees with adding ''T. falloti'' to it.

Classification

Although consistently recovered within the Somphospondyli, the exact placement of ''Tangvayosaurus'' is debated. It was initially assigned by Allain ''et al.'' (1999) to the

Titanosauria 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 ...

, who noted strong affinities to ''

'', which they also considered a titanosaur. A more recent review by Suteethorn ''et al.'' (2010) resolved both ''Tangvayosaurus'' and ''Phuwiangosaurus'' as more 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 (hence ...

s. The cladogram below follows this analysis. D'Emic (2012) found that ''Tangvayosaurus'' was the sister taxon of ''Phuwiangosaurus'' within the

Euhelopodidae Euhelopodidae is a family of sauropod 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 or ...

References

{{Taxonbar, from=Q135226 Macronarians Early Cretaceous dinosaurs of Asia Fossil taxa described in 1999 Taxa named by Philippe Taquet Taxa named by Octávio Mateus Fossils of Laos