It is based on TV4-1 to TV4-36, consisting of a partial pelvis, several back vertebrae 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, 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. Allain et al. also referred the old species "Titanosaurus" falloti (Hoffet, 1942),[2] from the same formation and based on partial thigh bones and tail vertebrae, to their genus as T. sp.[3] 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), but disagrees with adding T. falloti to it.[4]
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, who noted strong affinities to Phuwiangosaurus, which they also considered a titanosaur.[3] A more recent review by Suteethorn et al. (2010) resolved both Tangvayosaurus and Phuwiangosaurus as more basal titanosauriforms. The cladogram below follows this analysis.[5]
^J.-H. Hoffet. (1942). Description de quelques ossements de Titanosauriens du Sénonien du Bas-Laos [Description 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
^ abAllain, R.; Taquet, P.; Battail, B; Dejax, J.; Richir, P.; Véran, M.; Limon-Duparcmeur, F.; Vacant, R.; Mateus, O.; Sayarath, P.; Khenthavong, B.; Phouyavong, S. (1999). "Un nouveau genre de dinosaure sauropode de la formation des Grès supérieurs (Aptien-Albien) du Laos". Comptes Rendus de l'Académie des Sciences, Série IIA (in French). 329 (8): 609–616. Bibcode:1999CRASE.329..609A. doi:10.1016/S1251-8050(00)87218-3.
^Upchurch, Paul M.; Paul M. Barrett; Peter Dodson (2004). "Sauropoda". In Weishampel, David B.; Peter Dodson; Halszka Osmólska (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 259–322. ISBN0-520-24209-2.
^Suteethorn, S.; Le Loeuff, J.; Buffetaut, E.; Suteethorn, V. (2010). "Description of topotypes of Phuwiangosaurus sirindhornae, a sauropod from the Sao Khua Formation (Early Cretaceous) of Thailand, and their phylogenetic implications". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 256 (1): 109–121. doi:10.1127/0077-7749/2010/0036.
