26.9.16

Nuevo titanosauriforme de Morella en las VII Jornadas de Salas de los Infantes


Durante las VII Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno de Salas de los Infantes (España) se presentó una nueva comunicación sobre dinosaurios saurópodos del Cretácico Inferior de Morella. Este trabajo liderado por Pedro Mocho (Grupo de Biología Evolutiva de la UNED) se centra en el estudio del material de saurópodos encontrado en el yacimiento de Sant Antoni de la Vespa (Morella). Su descripción ha posibilitado incorporar uno de los tres ejemplares encontrados en este yacimiento y concluir que corresponde a un miembro de Titanosauriformes, y más concrétamente a una forma cercana al sauropodo Tastavinsaurus sanzi.

Titanosauriformes are recorded from the Upper Jurassic to the uppermost part of the Upper Cretaceous. Several new specimens have been reported in the Barremian‐Aptian sediments of the Iberian Peninsula, particularly in the Maestrazgo Basin. These new discoveries are improving our knowledge about the evolutionary history of this group in the European territory during the Early Cretaceous. The site of Sant Antoni de la Vespa (Arcillas de Morella Formation, upper Barremian; Morella, Castellón) was discovered in 1998. In 2005 and 2008, two excavation campaigns were conducted. At least, remains of three sauropod individuals were collected. The most complete one comprises an articulated posterior cervical‐to‐anterior dorsal vertebrae sequence (probably five vertebrae), ribs, caudal vertebrae, chevrons, pelvis elements, one leg including an almost articulated and complete pes, and the other incomplete limb. Near this specimen, ribs, caudal vertebrae and hindlimb elements of, at least, two other smaller individuals were identified, including two almost complete legs. All comparable elements present a similar morphology suggesting that they probably correspond to members of the same taxon. A brief description of Sant Antoni de la Vespa sauropods is provided, mainly based on one of the smaller individuals. The Sant Antoni de la Vespa sauropod presents several features commonly found within Titanosauriformes, such as the presence of a pronounced lateral bulge in the femur and an anteroposteriorly compressed femoral shaft (the lateromedial diameter of the shaft is 185% than the anteroposterior one). This sauropod also shares with more derived titanosauriforms than brachiosaurids the following features: i) crest‐like anterior trochanter on the fibula; ii) well‐developed trochanteric shelf in the femur; iii) transversely expanded tibial distal end; and iv) the presence of a well‐marked linea intermuscularis cranialis (shared by derived titanosaurs, including saltasaurines; Otero, 2010). Some distinctive features observed in one of the smaller specimens can be explained due to ontogeny. The Barremian‐Aptian sauropod faunas of the Iberian Peninsula include the titanosauriform Tastavinsaurus sanzi and the rebbachisaurid Demandasaurus darwini. A preliminary phylogenetic analysis places Sant Antoni de la Vespa sauropod within Titanosauriformes, in a phylogenetic position closely related with Tastavinsaurus. However, Sant Antoni de la Vespa sauropod does not share any authapomorphy of T. sanzi (see the revised diagnosis of Tastavinsaurus in Royo‐Torres et al., 2012) and both taxa mainly differ in the morphology of the femur and pes. This suggests that the Sant Antoni de la Vespa sauropod represents a different titanosauriform taxon. According to this, the known palaeodiversity of titanosauriforms for the Iberian realm during the Early Cretaceous seems to be higher than expected.

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