[D] Antarctosaurus giganteus
Cretaceous Late, Campanian Maastrichtian
Saurischia Sauropodomorpha Sauropoda Titanosauria
Rio Neuquen Formation , Provincia de Neuquen, Argentina
Antarctosaurus > Antarctosaurus wichmannianus (Huene, 1929) Antarctosaurus giganteus (Huene, 1929) > Antarctosaurus brasiliensis (Arid& Vizotto, 1972)
2 femora, pubis
Part of: Bonaparte, J. F. and Z. Gasparini. 1979. Los saurópodos de los grupos Neuquén y Chubut, y sus relaciones cronologicas. Actas del VII Congreso Geológico Argentino, Neuquén 2:393-406. [The sauropods of the Neuquén and Chubut groups and their chronological relations]
Translated by Jeffrey A. Wilson, Museum of Paleontology, University of Michigan, January 2003.
cf. Antarctosaurus giganteus Huene, 1929. An. Mus. La Plata, Paleont. Argentina. III, 2nd series, pp. 75-78, pls. 36; figs. 1-2.
Holotype: M.L.P. 26-316, two femora, two imcomplete pubes, incomplete distal extreme of a tibia, indeterminate fragments of six long bones, rib fragments, and two distal caudal vertebrae.
Geographic origin: Aguada del Caño, some 22 km west of Neuquén, Neuquén Province.
Stratigraphic and chronological origin: Neuquén Group, probably Rio Neuquen Formation, ?Plottier Member. Pre-Maastrichtian Senonian.
Commentary: The description and comparisons made by Huene (op. cit.) are very clear. Its affinities with Antarctosaurus wichmannianus are very significant, although not sufficient to refer it with certainty to the same [species].
They can be differentiated by its more gracile construction, with a proportionately slender diaphysis. In the opinion of Van Valen (1969), Antarctosaurus giganteus is the largest species of dinosaur registered. This same author has suggested that Antarctosaurus wichmannianus and Antarctosaurus giganteus are growth stages of the same species as they are “from the same strata”, translated from Van Valen (1969:624).
However, the actual statigraphic occurrence indicates that A. wichmannianus comes from the Río Colorado Formation, whereas Antarctosaurus giganteus very probably comes from the Rio Neuquen Formation. In that same 402 VII ongresso Geologico Agentino paper, Van Valen chose the name Antarctosaurus giganteus to include the material of the two species of Antarctosaurus. This is objectionable because Antarctosaurus wichmannianus has priority not only for having been described in earlier pages, but also for being based on better material. Nevertheless, in our opinion both Antarctosaurus wichmannianus and Antarctosaurus giganteus are valid species, and the stratigraphic evidence indicates that they were not contemporaries.
Source: Polyglot Paleontologist