Revision of the extinct Pleistocene tortoise Testudo lunellensis Almera and Bofill, 1903 from Cova de Gràcia (Barcelona, Spain)

Testudo lunellensis Almera and Bofill, 1903 from the Middle Pleistocene of Cova de Gràcia (Park Güell, Barcelona, Spain) is a valid species belonging to the clade of the extant Testudo hermanni – a diagnostic feature being the narrowed vertebral scutes. Thanks to still unpublished material, T. lunellensis is diagnosed for the first time and its shell morphology described in detail. This species is uniquely characterized, among others, by tall peripheral bones and by a peculiar shape of the anterior lobe of the plastron, somewhat recalling the species referred to Testudo s.s. (the clade containing the extant species Testudo graeca, Testudo kleinmanni and Testudo marginata). Given that the purported valid species from Lunel-Viel (Middle Pleistocene, France) is still unnamed and undescribed, T. lunellensis from Cova de Gràcia is currently the stratigraphically youngest extinct Testudo species. The co-occurrence in T. lunellensis of characters typical of both T. hermanni and Testudo s.s. further testifies the phenotypic plasticity of tortoises and the mosaic distribution of morphological characters, which hinders a clear-cut assessment of the relationships of extant tortoises when based exclusively on morphology. Further analyses of the phylogeny of Testudo should consider fossil and extant taxa together, as well as both morphological and genetic characters.