New Titanosauria (Dinosauria, Sauropoda) remains from the Upper Cretaceous (Plottier Fm) of the southern Neuquén Basin (Patagonia, Argentina)

BELLARDINI, FLAVIO; BAIANO, MATTIA A.; BARRIOS, FRANCISCO; HOLGADO, BORJA; CORIA, RODOLFO A.

JOURNAL OF IBERIAN GEOLOGY

SERVICIO PUBLICACIONES

Año: 2018 vol. 44 p. 75 - 84

1698-6180

Purpose New sauropod remains (MCF-PVPH-889, MCF-PVPH-899, and MCF-PVPH-900) collected from the PlottierFm (Coniacian?Santonian) in the south-west of the Neuquén Basin, are here reported. The materials proceed from a fluvialoutcrop composed by siltstone and fine sandstone, whose fossil record is known for large-sized sauropod taxa.Methods Due to the fragmentary condition of the dorsal ribs and the tibia, we focus the description mainly on the femurand the fibula.Results The specimen MCF-PVPH-889 consists of partially associated postcranial elements represented by a left femurand three fragmentary dorsal ribs of a Titanosauria indet. A right fibula (MCF-PVPH-900) represents another titanosaurianelement, while a proximal portion of a right tibia (MCF-PVPH-899) of a smaller individual than others is here referred to asa Sauropoda indet. MCF-PVPH-889 and MCF-PVPH-900 share some features with other titanosaurian taxa (e.g., a femurwith medial deflection of the proximal end and elliptical mid-shaft cross-section, a fibula with slightly sigmoidal shaft andwell-developed lateral tuberosity) like in Epachthosaurus and Antarctosaurus. However, the femur, with a poorly developedlateral bulge and a relatively low head, and a fibula, with a slender and nearly straight proximal third of the shaft, representplesiomorphic conditions among titanosaurians.Conclusions The new remains represent a new sauropod record from the Plottier Fm (Upper Cretaceous). Nevertheless,due to the lack of more diagnostic elements, we prefer to consider the specimens MCF-PVPH-889 and MCF-PVPH-900 asTitanosauria indet, and the MCF-PVPH-899 as Sauropoda indet. This new evidence expands the Coniacian sauropod recordof the Neuquén Basin and contributes, in some measure, to our knowledge of the stratigraphical distribution of sauropodsfrom the Patagonian Upper Cretaceous fossil-bearing levels.