ON DICRAEOSAURID (SAUROPODA) VERTEBRA FROM THE LA AMARGA FORMATION (BARREMIAN?APTIAN, LOWER CRETACEOUS), NEUQUÉN BASIN, PATAGONIA, ARGENTINA

WINDHOLZ, G.J.; BAIANO, M.A.; BELLARDINI, F.; MESO, J.; VALIERI JUAREZ, RUBEN; PORFIRI, JUAN; FILIPPI, L.S.; GARRIDO, A.C.

Neuquén

Jornada; 2DAS JORNADAS DE PALEOVERTEBRADOS DE LA CUENCA NEUQUINA; 2022

UNCO-APA-Ministerio Culturas Neuquén

Field works carried out by Dr. Bonaparte and collaborators in the La Amarga Formation (Barremian?Aptian) in 2000, allowedthe collecting of a vertebral element not previously communicated. This material has not been properly protected, so it isbroken and kept in paleontological collection of Museo Provincial ?Olsacher? of Zapala city. The descriptions were basedsolely on a photograph. The parapophyses are located on the dorsal part of the centrum, like in the anterior dorsal vertebraeof Dicraeosaurus hansemanni Janensch and Amargasaurus cazaui Salgado and Bonaparte. The posterior articular surfaceof the centrum is strongly concave with an elliptical outline. The neural arch bears two deep and wide centropostzygapophysealfossae with a triangular outline. These fossae are framed laterally by stout centropostzygapophyseal laminae,project dorsoventrally like a massive columnar bone. The transverse processes are inclined dorsally more than 30° fromthe horizontal axis, as in the dorsal vertebrae of D. hansemanni, A. cazaui, Brachytrachelopan mesai Rauhut, Remes, Fechner,Cladera and Puerta and Pilmatueia faundezi Coria, Windholz, Ortega and Currie. The element bears an elongate bifid neuralspine, character that share with the most of presacral vertebrae of the dicraeosaurids. This structure is straight, dorsoanteriorlyoriented and its degree of development reminds to the presacral vertebrae of A. cazaui. This element is similarto the anterior dorsal vertebrae of A. cazaui, although it could be comparable with Amargatitanis macni Apesteguía, comefrom the same locality and lithostratigraphic unit, whose presacral vertebrae are unknown.