La principal localidad donde se identifica material de tortugas del Albiense de la península ibérica corresponde a la mina de carbón de Ariño, en Teruel. En esta localidad destaca el hallazgo de esqueletos de este grupo de reptiles, algunos de ellos relativamente completos. Las tortugas basales son allí muy abundantes, ya sea mediante formas de agua dulce (representadas un taxón allí definido, Toremys cassiopeia, siendo el pleurostérnido más joven conocido a nivel global), como terrestres (identificadas mediante un heloquelídrido definido en Ariño y hasta ahora reconocido como exclusivo de esta localidad, Aragochersis lignitesta, así como a través de una segunda especie de este linaje, Plastremys lata, representando la referencia más antigua para esta especie con una relativamente amplia distribución europea). A estos hallazgos se une el reciente descubrimiento de miembros de un linaje de tortugas derivadas, correspondientes al linaje de Pan-Pleurodira. Se trata de un nuevo dortókido. La puesta al día sobre el conocimiento de las tortugas de Ariño ha sido defendida en un trabajo presentado en las XL Jornadas de la Sociedad Española de Paleontología, titulado “New data on the turtle diversity at the Santa Maria coal mine (Ariño, Teruel Province)”. Su resumen es el siguiente:
The vertebrate faunas of the Lower Cretaceous and those more characteristic of the Upper Cretaceous of Europe are radically different from each other. For this reason, the analysis of the few currently identified fossil sites in southwestern Europe corresponding to the end of the first of these Series (i.e., deposited during the Albian) and the beginning of the Upper Cretaceous (i.e., the Cenomanian) provide numerous new faunal data and are of vital importance to understand how this transition occurred. The Spanish Santa María coal mine (Ariño, Teruel Province) corresponds to the main Albian site, considering both the quantity of the fossils and the diversity recorded there. The turtles are well-represented in that lower Albian site. Two new taxa were recognized there. One of them is Toremys cassiopeia, corresponding to the youngest representative of the aquatic Pleurosternidae so far defined. The other is the helochelydrid Aragochersis lignitesta, represented by the most complete skeletons of this lineage of primitive terrestrial turtles recognized for the European record. New studies on the turtle remains from this locality allow us to recognize a greater diversity. Thus, the study of two additional taxa is presented here. One corresponds to a second form of Helochelydridae, whose presence had not been confirmed in the Iberian record until now, but which is shared with several European countries. Its identification in Ariño not only allows us to expand its paleobiogeographical distribution range but also its stratigraphical distribution, as it represents the oldest reference for the species. The other species studied here represents the only member of the crown Testudines in this locality. It is identified as a member of Pan-Pleurodira and, more specifically, of Dortokidae. Its identification is a relevant discovery given that it falls within a long temporal gap for the record of this lineage.
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