A new basal turtle represented by the two most complete skeletons of Helochelydridae in Europe

Abstract Two partial skeletons attributable to a single basal turtle taxon (i.e., Testudinata not belonging to the crown group Testudines) are studied here. These specimens come from the lower Albian (Lower Cretaceous) of the lignite coal mine of Santa Maria, in Arino (Teruel Province, Aragon, northeastern Spain). They are identified as belonging to a new member of the clade of terrestrial turtles Helochelydridae, Aragochersis lignitesta gen. et sp. nov. Both specimens represent the most complete skeletons of this lineage so far identified in Europe. The skull and mandible of the new taxon, but also the shell, several vertebrae, and numerous elements of the appendicular skeleton, are preserved. New anatomical information about this relatively poorly known group of basal turtles is provided.