Phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs were determined by geological processes and climate change in the Late Cenozoic

Abstract

Aim Our aims were to assess the phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs and to estimate divergence times using different geological scenarios. We related divergence times to past geological events and discuss the relevance of our data for the systematics of eastern Mediterranean water frogs. Location The eastern Mediterranean region. Methods Genetic diversity and divergence were calculated using sequences of two protein-coding mitochondrial (mt) genes: ND2 (1038 bp, 119 sequences) and ND3 (340 bp, 612 sequences). Divergence times were estimated in a Bayesian framework under four geological scenarios representing alternative possible geological histories for the eastern Mediterranean. We then compared the different scenarios using Bayes factors and additional geological data. Results Extensive genetic diversity in mtDNA divides eastern Mediterranean water frogs into six main haplogroups (MHG). Three MHGs were identified on the Anatolian mainland; the most widespread MHG with the highest diversity is distributed from western Anatolia to the northern shore of the Caspian Sea, including the type locality of Pelophylax ridibundus. The other two Anatolian MHGs are restricted to south-eastern Turkey, occupying localities west and east of the Amanos mountain range. One of the remaining three MHGs is restricted to Cyprus; a second to the Levant; the third was found in the distribution area of European lake frogs (P. ridibundus group), including the Balkans. Main conclusions Based on geological evidence and estimates of genetic divergence we hypothesize that the water frogs of Cyprus have been isolated from the Anatolian mainland populations since the end of the Messinian salinity crisis (MSC), i.e. since c. 5.5-5.3 Ma, while our divergence time estimates indicate that the isolation of Crete from the mainland populations (Peloponnese, Anatolia) most likely pre-dates the MSC. The observed rates of divergence imply a time window of c. 1.6-1.1 million years for diversification of the largest Anatolian MHG; divergence between the two other Anatolian MHGs may have begun about 3.0 Ma, apparently as a result of uplift of the Amanos Mountains. Our mtDNA data suggest that the Anatolian water frogs and frogs from Cyprus represent several undescribed species.

Cryptic diversity within the Anatololacerta species complex (Squamata: Lacertidae) in the Anatolian Peninsula: Evidence from a multi-locus approach

“…For instance, Ophisops elegans shows four distinct genetic lineages in Anatolia (Kyriazi et al, 2008). The Anatolian water frogs exhibit a similar pattern with various lineages having been identified (Plötner et al, 2001;Akın et al, 2010). Fritz et al (2007) revealed the existence of several mtDNA varieties of Testudo graeca in Anatolia, that were assigned to specific level, and were also confirmed in some cases by a thorough morphological approach (Türkozan et al, 2010).…”

“…Particularly in the south, the Anatolian mountains played an important role in speciation and definition of biogeographical subregions, promoting endemisms and great intraspecific genetic diversity in this area (Çıplak, 2003, 2004 and references therein). Accordingly, several cryptic genetic lineages of amphibians and reptiles showing continuous geographic distributions in Anatolia have been revealed (Kyriazi et al, 2008;Plötner et al, 2001;Akın et al, 2010;Fritz et al, 2007).…”

Invasiveness of an introduced species: the role of hybridization and ecological constraints

“…This resulted in a high genetic heterogeneity of the introduced frogs because substantial differences exist among taxa within the ''P. ridibundus'' group (Holsbeek et al 2008;Plénet et al 2009;Akin et al 2010;Plötner et al 2010). Especially in France, the expansion range has increased since the middle of the twentieth century because of repeated introductions of live water frogs (Pagano et al 2001;Schmeller et al 2005; but also see Plötner 2005).…”

Molecular systematics and phylogeography of Bufotes variabilis (syn. Pseudepidalea variabilis) (Pallas, 1769) in Turkey

“…They stated that the Anatolian peninsula is a predominantly mountainous area whose diverse geomorphology produces many different climatic regions and vegetation types. In addition, Akın et al (2010) indicated that 2 clades of water frogs may have split from the uplift of the Taurus Mountains, and they also showed phylogeographic patterns of genetic diversity for water frogs as determined by geological processes and climate in Anatolia. During the Tertiary and Quaternary, Anatolia acted either as a bridge or as a barrier for species dispersal between Asia and Europe, providing a natural pathway or acting as a vicariant agent (Tchernov, 1992).…”