27.9.16

Una de dortókidos en las VII Jornadas de Salas de Los Infantes


Los dortókidos son un grupo de tortugas pleurodiras primitivas, con un registro relativamente bueno en el Cretácico Superior. Sin embargo, hasta ahora se dispone de información muy escasa sobre los representantes más antiguos de este grupo, debido al limitado registro disponible en niveles del Cretácico Inferior. Un nuevo ejemplar, presentado en las VII Jornadas de Salas de Los Infantes, permite conocer algo más sobre estas primeras formas.

El resumen de esta contribución es el siguiente:

Dortokidae is a poorly known group of Pan-Pleurodira, exclusive to Europe. This clade is recognized as belonging to the stem group of Pleurodira. The dortokids are the only members of this stem group known in the Laurasian post-Jurassic record. Dortokidae is a lineage known from the Early Cretaceous to the Paleogene (Lapparent de Broin et al., 2004; Pérez-García et al., 2014). The oldest representative so far defined has recently been described: Eodortoka morellana, from the Barremian of Morella (Castellón, Spain) (Pérez-García et al., 2014). Although the material of Dortokidae from the Upper Cretaceous and Paleogene is relatively abundant, that of the Lower Cretaceous is very scarce. In fact, only another reference for the discovery of Dortokidae in the Lower Cretaceous levels in known: a finding reported in the Barremian of Vallipón (Teruel, Spain) (Murelaga Bereikua, 1998). Therefore, very little knowledge about the Lower Cretaceous forms of Dortokidae is so far available, but also the phylogenetic relationships between the representatives of Dortokidae are poorly known.
An element attributable to Dortokidae, from a Lower Cretaceous locality of Teruel where this group had not been recognized until now, is identified here. It corresponds to a partial plate of the plastron. This finding occurs in a formation where several groups of turtles had been identified (Pérez-García et al., 2013): Solemydidae, Pleurosternidae, Xinjiangchelyidae and, now, also Dortokidae. In addition, the study of abundant material of Dortokidae allows us the better characterization of the previously described members of this clade, in order to propose a new hypothesis about the phylogenetic relationships among the dortokids. Thus, the biostratigraphic and paleobiogeographic distributions of the representatives of this group are analyzed, and the oldest known reference to Dortokidae is presented here.
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