Phylogeography of Balkan wall lizard (Podarcis taurica) and its relatives inferred from mitochondrial DNA sequences

Abstract

Wall lizards of the genus Podarcis (Sauria, Lacertidae) comprise 17 currently recognized species in southern Europe, where they are the predominant reptile group. The taxonomy of Podarcis is complex and unstable. Based on DNA sequence data the species of Podarcis falls into four main groups that have substantial geographical conherence (western island group, southwestern group, Italian group and Balkan group). The Balkan species are divided in two subgroups: the subgroup of Podarcis taurica (P. taurica, P. milensis, P. gaigeae and perhaps P. melisellensis), and the subgroup of Podarcis erhardii (P. erhardii and P. peloponnesiaca). We addressed the question of phylogenetic relations among the species of the P. taurica subgroup encountered in Greece, as they can be inferred from partial mtDNA (cyt b and 16S) sequences. Our data support the monophyly of P. taurica subgroup and suggest that P. gaigeae, P. milensis and P. melisellensis form a clade, which thereinafter connects to P. taurica. Within the previous clade, P. gaigeae is more closely related to P. milensis than to P. melisellensis. However, the specimens of P. taurica were subdivided in two different groups. The first one includes the specimens from northeastern Greece, and the other group includes the specimens from the rest of continental Greece and Ionian islands. Because the molecular clock of the cyt b and 16 rRNA genes was not rejected in our model test, it is possible to estimate times of speciation events. Based on the splitting of the island of Crete from Peloponnisos [c. 5 million years ago (Ma)], the evolutionary rate for the cyt b is 1.55% per million years (Myr) and for the 16S rRNA is 0.46% per Myr. These results suggest that the evolutionary history of P. taurica in Greece is more complex than a single evolutionary invasion. The data analysed, stress the need for a reconsideration of the evolutionary history of Greek Podarcis species and help overcome difficulties that classical taxonomy has encountered at both the species level.

Three Continents Claiming an Archipelago: The Evolution of Aegean’s Herpetofaunal Diversity

“…The second group (P. taurica), largely overlapping with the previous one in time and space, has a similar history in the area [4]. The interaction of the two species groups appears as another factor that influenced present day distributions ( Figure 5).…”

“…Their locations are determined by complex historical and environmental factors, the cumulative effects of which need to be considered because they have occurred since the Tertiary, rather than solely during the last glacial period [68]. Moreover, we should keep an open mind about the role of refugia apart from on the Mediterranean peninsulas or near the sea as discussed in e.g., [25,69] and suggested in other works [4,21]. Additionally, proposed refugia should be critically and case-by-case assessed as what is a refuge for one species is not necessarily for another.…”

“…Of the other islands, only Samothrake and Evvoia have peaks over 1,500 m and less than 10 islands have altitudes over 1,000 m. On the continental area, three mountain ranges appear to have played an important role in the shaping of the contemporary herpetofauna: the Pindos mountain range crossing continental Greece from north to south creating an east-west barrier; the Rhodope mountain range between Greece and Bulgaria often delimiting the southernmost distribution of northern taxa and the Taurus and Antitaurus mountain ranges in Turkey filtering organisms dispersal. [4].…”

“…Another uncertain case is the one of Macrovipera, which has been assumed to have split during the Messinian crisis [43]. However, M. schweizeri shares the Milos island group with Podarcis milensis which has been suggested to have split from mainland populations circa 8 MYA [4], a time compatible with the opening of the MAT. The opening of the MAT resulted in a vicariant splitting of populations, which may or may not be evident today.…”

New locality record of Podarcis tauricus tauricus (Pallas, 1814) (Squamata: Lacertidae) from the western Black Sea region of Turkey

“…However, our conclusion is not dependent on molecular data. Based on their molecular data, Poulakakis et al (2005) stated that their specimens of Balkan wall lizard were subdivided into 2 different groups: the first one included the specimens from northeastern Greece (P. t. tauricus and P. t. thasopulae), and the other group included the specimens from the rest of continental Greece (P. t. tauricus) and the Ionian islands (P. t. ionicus). Phylogenetic relationships among Turkish populations of P. t. tauricus have not been investigated.…”