INVESTIGADORES
GIANECHINI Federico Abel
congresos y reuniones científicas
Título:
NEW DINOSAUR REMAINS FROM THE BAJADA COLORADA FORMATION (BERRIASAN-?VALANGINIAN): NOTES ON THE EARLIEST CRETACEOUS DINOSAURS FROM THE NEUQUEN BASIN, PATAGONIA, ARGENTINA
Autor/es:
FEDERICO A. GIANECHINI; SEBASTIÁN APESTEGUÍA; JUAN CANALE; PABLO A. GALLINA; ALEJANDRO HALUZA
Lugar:
San Juan
Reunión:
Congreso; IV Congreso Latinoamericano de Paleontología de Vertebrados; 2011
Resumen:
Patagonia yielded one of the best samples worldwide of Late Cretaceous terrestrial tetrapods, especially in Gondwanan continents. However, despite few but successful efforts (e.g., Salgado and Bonaparte, 1991; Bonaparte et al., 2006), most of its Early Cretaceous outcrops remain virtually unexplored, especially in northern Patagonia. The Bajada Colorada Formation (Berriasan-?Valanginian), whose sedimentites crops out in northwestern Patagonia, Neuquén Province, represents the most basal Cretaceous continental unit in the Neuquén Basin. The first dinosaur records from this unit were briefly communicated by Apesteguía and Bonaparte (2004), consisting in a sauropod dorsal vertebra referred to a diplodocoid and a fragmentary theropod femur with tetanuran affinities. Here we report new findings, consisting in a tooth and a cervical neural arch assigned to a theropod dinosaur, as well as a complete mid-caudal vertebra assigned to a sauropod. The tooth is labiolingually compressed, with mesial and distal serrated carinae and a slightly eight-shaped transversal basal section. The mesial carina is limited to the distal medium height of the crown. This dental morphology resembles that of basal tetanurans. The cervical neural arch is characterized by long, laminar, and anteroventrally projected diapophyses, and anterodorsally projected prezygapophyses, resulting in an ?X-shaped? form in anterior view. These traits resemble those present in cervical vertebrae of abelisaurids. On the other hand, the complete mid caudal vertebra present an amphiplathyan centrum with strongly concave ventral surfaces and pronounced lateral borders. The neural arch shows elevated pillars located on the mid-anterior portion of the centrum. While prezygapophyses are anterodorsally projected, the laminar neural spine points upwards and backwards, being connected by well developed spinoprezygapophyseal laminae. Despite the overall morphology of this vertebra resembles that of basal macronarian sauropods, its centrum resembles that of diplodocids (e.g., Diplodocus Marsh, 1878). These materials were found in close association with fragmentary remains of vertebrae, long bones and a poorly-preserved coracoid. More efforts are necessary in order to understand the faunal components that followed the Jurassic fauna of Patagonia and how Late Cretaceous faunas arose. This new record contributes to increase the knowledge of basal Cretaceous assemblages of Patagonia.