This article deals with the fossil tortoises of one of the most iconic fossil localities
of the Neogene of the Old World, the upper Miocene locality of Pikermi, near Athens,
Greece. We describe the type, previously published, and new material of the fossil
tortoises from Pikermi, along with new material from the coeval Azmaka 6 locality
in Bulgaria. This combined information results in the complete revision of the 'marble
tortoise' Testudo marmorum, which is the first turtle species ever named from Greece.
Besides the challenges and difficulties of working with material from the old collections
of Pikermi, we present a complete revision of this species and identify its presence
outside its type locality in the South Balkan Peninsula. The presence of numerous
shells of the 'marble tortoise' allows us to discuss the observed variation and attempt
to interpret it as the result of intraspecific variation, ontogenetic changes, or
sexual dimorphism. For the first time, we observe the absence of the characteristic
hypo-xiphiplastral hinge in female individuals of Testudo marmorum, which in turn
challenges the traditional phylogenetic position of this species. We further describe
previously published and new material of the giant tortoise Titanochelon from Pikermi.
Based on the updated information, we can suggest that the Pikermian giant tortoise
probably represents a distinct taxon. Our results signal Pikermi as one of the most
important localities to understand the evolution of tortoises in the eastern Mediterranean
during the last parts of the Neogene.
