Podarcis latastei - Western Pontine Wall Lizard
In 2019, a new Podarcis species has been described for the Western Pontine Islands (Ponza, Palmarola, Zannone and some small islets): Podarcis latastei, which has been formerly regarded as subspecies of Podarcis siculus. First of all, putting any Podarcis island population into species rank seems questionable, as there appears to be a general taxonomic trend to "supersplitting". However, the analysis by SENCZUK et al. clearly shows that the genentic distance between the Western Pontine Wall Lizards and Podarcis siculus on Italian mainland is sufficiently big to justify a new taxon.
Still, the paleogeography of the Western Pontine Islands raises some questions, though: SENZCUK et al. mention that the Western Pontine Islands are supposed to have been connected with the Italian mainland in Pleistocene, and have been isolated afterwards. In this case, the isolation period would have been rather short for development of a new species. However detailed data about Pleistocene continental shelf deposits and coastlines seem to be deficient (see MARTORELLI et al.).
Furthermore, the Western Pontine Islands emerged by volcanic activity, which raises doubts if the islands were suitable lizard habitats at all. But it seems that major clastic activities ended some 3 million years ago (see CADOUX et al.), presumably leaving sufficient time for subsequent lizard colonization and species differentiation.
Regarding the current state of knowledge of the Western Pontine Islands' paleogeography and the genetic results, we believe that Podarcis latastei should be acknowledged as a seperate species. So far, we did not have the opportunity to visit these islands. Pictures of the Western Pontine Wall Lizard can be found here.
References:
CADOUX, A. & PINTI, D. & AZNAR, C. & CHIES, S. & GILLOT, P. (2005) - New chronological and geochemical constraints on the genesis and geological evolution of Ponza and Palmarola Volcanic Islands (Tyrrhenian Sea, Italy) - Lithos 81(1):121-151.
MARTORELLI, E. & FALESE, F. & CHIOCCI, F. L. (2014) - Chapter 12 Overview of the variability of Late Quaternary continental shelf deposits of the Italian peninsula - Geological Society, London, Memoirs, 41, 171-186.
SENCZUK, G. & CASTIGLIA, R. & BÖHME, W. & CORTI, C. (2019) - Podarcis siculus latastei (Bedriaga, 1879) of the western Pontine islands (Italy) raised to the species rank, and a brief taxonomic overview of Podarcis lizards. - Acta Herpetologica, 14 (2): 71-80.
