Molecular systematics and historical biogeography of the green lizards (Lacerta) in Greece: Insights from mitochondrial and nuclear DNA

Abstract

The green lizards of the genus Lacerta (Sauria, Lacertidae) comprise nine recognized species, which in Europe are mainly restricted to the southern peninsulas. Four of them (L. trilineata, L. viridis, L. bilineata and L. agilis) occur in Greece. The uncertainty of morphological diversification renders the taxonomic assignment into species and subspecies problematic. In this study sequence data derived from two mitochondrial (cytochrome b and 16S rRNA) genes and one nuclear (NKTR) gene were used to (a) evaluate the taxonomic status of the genus Lacerta in Greece with emphasis on L. trilineata group and (b) investigate the evolutionary history of the genus through the application of phylogenetic and phylogeographic analyses, using Gallotia and Timon as outgroups. The phylogenetic analyses revealed the existence of four major clades. The first clade corresponds to L. trilineata group, the second to L. media, the third to L. agilis and the fourth to a complex of L. viridis and L. bilineata. However, the produced phylogenetic relationships are not congruent with the current taxonomy, especially in the first clade in which L. trilineata appeared to be paraphyletic in regard to L. pamphylica. Six distinct lineages were inferred within L. trilineata, despite the current recognition of nine morphological subspecies, the genetic differentiation of which exceeds that of other Lacerta species, imposing a thorough taxonomic revision of the species. Our results suggested a rapid diversification of L. trilineata group during the late Miocene. We believe that the present distribution of the genus in Greece is the result of several dispersal and vicariant events that took place during the late Miocene and early Pliocene.