Changes in vertebral laminae of a well-preserved rebbachisaurid

Alejandro Haluza, Juan I. Canale, Alejandro Otero, Leandro M. Pérez & Carlos A. Scanferla

The fossil record of rebbachisaurid sauropods has greatly increased recently (Calvo and Salgado, 1995; Bonaparte, 1996; Dalla Vecchia, 1998; Sereno et al., 1999, 2007; Medeiros and Schultz, 2001; Pereda-Suberbiola et al., 2001, 2003; Salgado et al., 2004, 2006; Gallina and Apesteguía, 2005; Apesteguía, 2007; Mannion, 2009). The first fossil remains belonging to this group were described by Nopcsa (1902) but only recently recognized as a rebbachisaurid (Calvo and Salgado, 1995; Apestegu´ıa, 2007). Lavocat (1954) erected Rebbachisaurus garasbae, which has a scapula with broad, ‘racquet’-shaped blade, and a mid-dorsal vertebra with a very tall neural spine. This family is mostly known from rather fragmentary remains, and many specimens are unpublished or only partially described (Gallina and Apestegu´ıa, 2005). In this contribution, we present new materials assignable to Rebbachisauridae, recovered from the Huincul Formation, Neuquén Group, near Villa El Chocón, Neuquén Province. The lowermost section of this geological unit has yielded other dinosaur taxa, such as Skorpiovenator bustingorryi (Canale et al., 2009). The rebbachisaurid remains correspond to a single, partially articulated, and exceptionally preserved skeleton, which includes cervical and dorsal vertebrae, thoracic ribs, scapula, and a humerus. The importance of studying complete serial elements of the skeleton (e.g., vertebral series) lies on the ability to track specific elements (i.e., landmarks), which are useful to unambiguously recognize homologous structures (Wilson, 1999; Otero et al., In press; Wilson et al., 2011). In this regard, the preserved cervicodorsal series described herein gives remarkable anatomical and systematic information, allowing the recognition of the transitional morphology, topology, and extent of the vertebral laminae

Haluza, A., Canale, J. I., Otero, A.,  Pérez, L. M., and Scanferla, C., 2012.Changes in vertebral laminae across the cervicodorsal transition of a well-preserved rebbachisaurid (Dinosauria, Sauropoda) from the Cenomanian of Patagonia, Argentina, Journal of Vertebrate Paleontology, 32:1, 219-224.