On dicraeosaurid (Sauropoda) vertebra from the La Amarga Formation (Barremian-Aptian, Lower Cretaceous), Neuquén Basin, Patagonia, Argentina

MATTIA ANTONIO BAIANO; RUBEN JUAREZ VALIERI; ALBERTO GARRIDO; GUILLERMO WINDHOLZ; JORGE GUSTAVO MESO; LEONARDO FILIPPI; FLAVIO BELLARDINI; JUAN PORFIRI

Neuquén

Congreso; II Jornadas de Paleovertebrados de la Cuenca Neuquina; 2019

Universidad Nacional del Comahue

Field works carried out by Dr. Bonaparte and collaborators in the La Amarga Formation (Barremian-Aptian) in 2000, allowed the collecting of a vertebral element not previously communicated. This material has not been properly protected, so it is broken and keeps in paleontological collection of Museo Provincial ?Olsacher? of Zapala city. The descriptions were based solely on a photograph. The parapophyses are located on the dorsal part of the centrum, like in the anterior dorsal vertebrae of Dicraeosaurus hansemanni Janensch 1914 and Amargasaurus cazaui Salgado and Bonaparte 1991. The posterior articular surface of the centrum is strongly concave with an elliptical outline. The neural arch bears two deep and wide centropostzygapophyseal fossae 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° from the horizontal axis, as in the dorsal vertebrae of D. hansemanni, A. cazaui, Brachytrachelopan mesai Rauhut, Remes, Fechner, Cladera and Puerta 2005 and Pilmatueia faundezi Coria, Windholz, Ortega and Currie 2019. The element bears an elongate bifid neural spine, character that share with the most of presacral vertebrae of the dicraeosaurids. This structure is straight, dorsoanteriorly oriented and its degree of development reminds to the presacral