Turtle remains from the late Miocene of the Cessaniti area, southern Italy—insights for a probable Tortonian chelonian dispersal from Europe to Africa

Georgios L. Georgalis,Lorenzo Rook,Gianni Insacco,Filippo Spadola,Massimo Delfino

doi:10.1186/s13358-020-00202-y

Abstract

We here describe turtle remains from the late Miocene (Tortonian) of Cessaniti (Calabria, southern Italy), an area that recently has been palaeogeographically reconstructed as being, at that time of the Neogene, directly connected (or at least rather proximate) to northern Africa, instead of Europe. The material pertains to three different turtle clades, i.e., pan-trionychids, pan-cheloniids, and pan-geoemydids. Although the material is incomplete, it nevertheless permits a more precise identification for the pan-trionychid specimens, which are referred to the species Trionyx pliocenicus, as well as the pan-geoemydid, which is attributed to the genus Mauremys. Especially for the case of T. pliocenicus, the new Cessaniti specimens expand its geographic and stratigraphic distribution and further comprise the sole existing material known for this species, considering that its holotype and so far only known material is currently lost. Overall, besides its taxonomic significance, the Cessaniti chelonian assemblage affords the potential for important biogeographic implications, attesting that the lineages of Trionyx and Mauremys could have potentially used the Sicily–Calabria arch for their dispersal from Europe to Africa during the Tortonian. The new turtle specimens further complement the associated mammal remains in envisaging the Cessaniti assemblage as a mosaic of both African and Eurasian (Pikermian) faunal elements.

Highlights

The palaeogeography of Europe and adjacent areas has been subjected to significant alterations throughout the Neogene (Rögl 1999; Meulenkamp and Sissingh 2003)
Fossil evidence from southern Italy has recently allowed the identification of another, not yet so well-known palaeobioprovince testified by sites in Calabria and Sicily characterized by non-endemic mammals, counterparts of which were identified in both North Africa and Europe (Rook et al 2008)
The identification of the elephantid proboscidean Stegotetrabelodon syrticus in the late Miocene (Tortonian) of the Cessaniti area, Calabria, southern Italy, has led to the suggestion that, during that time interval, the Sicily–Calabria arch (Siculo–Calabrian arc) was united with northern Africa, forming part of the latter continent and not Europe (Ferretti et al 2003)

Summary

Introduction

The palaeogeography of Europe and adjacent areas has been subjected to significant alterations throughout the Neogene (Rögl 1999; Meulenkamp and Sissingh 2003). The identification of the elephantid proboscidean Stegotetrabelodon syrticus (which is of clear African origin) in the late Miocene (Tortonian) of the Cessaniti area, Calabria, southern Italy, has led to the suggestion that, during that time interval, the Sicily–Calabria arch (Siculo–Calabrian arc) was united with northern Africa, forming part of the latter continent and not Europe (Ferretti et al 2003). In order to improve the knowledge of this palaeobioprovince, that has been based so far on mammals only, we here describe for the first time reptile finds from the Cessaniti area. This material, represented by turtle remains recovered from those localities, pertains to three different lineages and provides an opportunity to assess the previous palaeogeographic reconstructions and test the previously suggested biogeographic scenarios

Methods

Discussion

Conclusion