Saurópodo juvenil del Cretácico Superior de Lo Hueco en el XI Congreso Anual de la EAVP

Este año, el XI European Association of Vertebrate Palaeontologists (EAVP) Meeting se ha desarrollado Villers-sur-Mer (pueblecito con encanto situado al norte de Normandía) entre el 11 y el 15 de junio.

Y (por supuesto) los fósiles de Lo Hueco (Cretácico Superior. Fuentes, Cuenca) han hecho acto de presencia mediante a un póster en el que se detalla la descripción de unas vértebras dorsales de pequeño tamaño referidas a un titanosaurio juvenil del yacimiento. Además del intereés de los caracteres más diagnósticos de estos ejemplares, se ha analizado en detalle la variación de las láminas y fosas existente.

Vamos con el resumen que justifica el desembarco en Normandía de este chiquitín:

Dorsal vertebrae of a juvenile titanosaur from the Late Cretaceous of “Lo Hueco” (Cuenca, Spain)

The fossil site of “Lo Hueco” from the Late Cretaceous of Cuenca (central Spain) has yielded more than 8000 fossil remains, 49 % referred to titanosaurian sauropods. Recent studies hypothesize the presence of several titanosaurian morphotypes corresponding to, at least, two different taxa. Two of these morphotypes are also present in several sites from France (Díez Díaz et al., 2012; Knoll et al., 2013). A third one could have been a gracile morphotype not known in other sites until now.

Here we present five small titanosaurian dorsal vertebrae (they are non consecutive, but most likely belonging to a single individual) found at “Lo Hueco”. The neural arch and the centrum are not completely co-osified in two of them, so they probably belonged to a juvenile individual. The centra are long and opisthocoelous, being dorsoventrally compressed in the more anterior vertebrae. They show an eyed-shaped pleurocoel at their lateral surfaces. The neural spine is low and posterodorsally oriented. The diapophyses are almost horizontally oriented. These vertebrae present a complex lamination, which surrounds numerous deep fossae. The most striking features of these specimens are the presence of a stranded prespinal lamina and a longitudinal ridge in the interpostzygapophyseal lamina in the most anterior ones, and a stranded posterior parapophyseal lamina in the most posterior ones (sensu Wilson, 2013).

These vertebrae present a characters combination corresponding to a lithostrotian titanosaur. They do not share the diagnosis of any of the Iberoarmorican titanosaurs know until now, but further adscription has to be cautelous as they correspond to a juvenile individual. The study of the rest of the titanosaurian remains from “Lo Hueco” will help to assess the taxonomic status of these dorsal vertebrae and probably shed light to understand the ontogenic character transformation of one of the taxon represented in the site.

References:
Díez Díaz, V., Le Loeuff, J., Ortega, F., Pereda Suberbiola, X., and Sanz, J.L. 2012. Titanosaurs: the largest vertebrate settlers of the Ibero-Armorican Island. Fundamental!, 20: 67-69.

Knoll, F., Ridgely, R.C., Ortega, F., Sanz, J.L., and Witmer, L.M. 2013. Neurocranial Osteology and Neuroanatomy of a Late Cretaceous Titanosaurian Sauropod from Spain (Ampelosaurus sp.). PLoS ONE 8 (1): e54991. doi:10.1371/journal.pone.0054991

Wilson, J.A. 2012. New vertebral laminae and patterns of serial variation in vertebral laminae of sauropod dinosaurs. Contributions from the Museum of Paleontology, University of Michigan 32: 91–110.