ABSTRACT-The occurrence of freshwater turtle remains in the late Miocene lignites of southern Tuscany (Montebamboli and Casteani, Italy) has been known since the nineteenth century. Three chelonian species were recognized by Ristori in 1891: Emys depressa, E. campanii, and E. parva. Revision of their type material, together with the study of new fossils from a different but correlated locality, Pian Calcinaio (Scansano), allows one to state that they can be referred to the genus Mauremys and that they belong to one single species. The new combination M. campanii (Ristori, 1891) is here proposed. Phylogenetic analysis indicates that M. campanii is closely related to the modern post-Miocene group of Mauremys species and shows a sister-group relationship with the Plio-Pleistocene M. gaudryi. The remains of M. campanii come from an insular setting which progressively lost its endemic mammal fauna, defined as the Oreopithecus Zone Fauna, enabling us to compare the pattern of survival of the chelonians with that of the mammals. In contrast to the radical turnover suffered by mammals, softshell turtles (Trionyx sp.) and terrapins (M. campanii) are present both in the pre-Messinian V1-V2 and Messinian V3 assemblages. Terrestrial tortoises (Testudo amiatae Pantanelli, 1893, Testudo s.l.) show a different pattern, because they appear only in the V3 assemblage, possibly because they apparently dispersed into Italy as recently as the Messinian. M. campanii represents the southernmost evidence of the genus Mauremys in the uppermost Miocene of Europe, filling a gap in the palaeogeographic and chronological distribution of this genus.
-Psephophorus polygonus Meyer, 1847, the first fossil leatherback turtle to be named, was described on the basis of shell ossicles from the middle Miocene (MN6-7/8?) of Slovakia. The whereabouts of this material is uncertain but a slab on display at the Naturhistorisches Museum Wien is considered the neotype. We rediscovered further type locality ossicles in four European institutions, re-evaluated their gross morphology and described for the first time their microstructure by comparing them with Dermochelys coriacea, the only living dermochelyid turtle. The gross morphology is congruent with that already described for P. polygonus, but with two significant exceptions: the ridged ossicles of P. polygonus may have a distinctly concave ventral surface as well as a tectiform shape in cross-section. They do not develop the external keel typical of many ossicles of D. coriacea. Both ridged and non-ridged ossicles of P. polygonus are characterized by compact diploe structures with an internal cortex consisting of a coarse fibrous meshwork, whereas the proportionately thinner ossicles of D. coriacea tend to lose the internal cortex, and thus their diploe, during ontogeny. The ossicles of both P. polygonus and D. coriacea differ from those of other lineages of amniotes whose carapace is composed of polygonal ossicles or platelets, in having growth centres situated at the plate centres just interior to the external bone surface and not within the cancellous core or closer to the internal compact layer. The new diagnosis of P. polygonus allows us to preliminarily re-evaluate the taxonomy of some of the Psephophorus-like species. Despite some macro-and micromorphological differences, it seems likely that Psephophorus was as cosmopolitan as extant Dermochelys and had a broadly similar ecology, with a possible difference concerning the dive depth.
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