Argyrosaurus superbus is one of the earliest-named Argentinean dinosaurs. The holotype comprises a complete forelimb, probably from the upper member of the Bajo Barreal Formation (Late Cretaceous), Chubut Province. Numerous remains have been referred to Argyrosaurus from Argentina and Uruguay; however, the type specimen has not been adequately diagnosed and referrals have predominantly been based upon their large size. Here we redescribe Argyrosaurus, demonstrating it to be a valid titanosaur genus based on five autapomorphies, as well as an unique character combination. The exact placement of Argyrosaurus within Titanosauria is uncertain, although the probable presence of carpal bones, otherwise unknown in titanosaurs, may indicate a basal position. None of the referred remains can be attributed to Argyrosaurus, and most should be regarded as indeterminate titanosauriforms. The exception to this is a partial skeleton from the lower member of the Bajo Barreal Formation (early Late Cretaceous), Chubut Province, comprising dorsal and caudal vertebrae, as well as numerous appendicular elements. This specimen is distinct from Argyrosaurus and can also be differentiated from other sauropods based on an unusual character combination (including plesiomorphic tarsus), plus one autapomorphy. Elaltitan lilloi, gen. et sp. nov., displays numerous titanosaur characters and shares several features with derived taxa such as Neuquensaurus, Opisthocoelicaudia, Rapetosaurus, Saltasaurus, and Trigonosaurus. Elaltitan can be referred to Lithostrotia; however, its precise position within this clade must await future phylogenetic analysis. The revision and description of the titanosaurs Argyrosaurus and Elaltitan provides new information on this diverse but still poorly understood clade.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.