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Testing biogeographical hypotheses in space and time: faunal relationships of the putative ancient Lake Eg[caron]irdir in Asia Minor

Wilke, Thomas, Albrecht, Christian, Anistratenko, Vitaliy V., Sahin, Serap Kosal, Yildirim, Mehmet Zeki
Journal of biogeography 2007 v.34 no.10 pp. 1807-1821
Bayesian theory, DNA, biodiversity, biogeography, fauna, fossils, invertebrates, lakes, models, monophyly, nucleotide sequences, space and time, Turkey (country)
The aims of this study are to establish a multi-locus phylogeny-based hypothesis for the biogeographical relationship of gastropods from the putative ancient Lake Eg[caron]irdir, to test the respective null hypothesis, to estimate the timing of biogeographical events based on independent molecular clock approaches, and to interpret the data with respect to the putative ancient character of Lake Eg[caron]irdir. Lake Eg[caron]irdir, western Taurus Lake District, Turkey. DNA sequences from the putatively only extant endemic taxon of Lake Eg[caron]irdir, Falsipyrgula pfeiferi, as well as representatives of other pyrgulinid genera from Europe and western Asia are used for phylogenetic analyses based on Bayesian inference. The respective null hypothesis is tested utilizing parametric bootstrapping. The timing of evolutionary events is estimated based on two independent molecular clock approaches, which involve the modelling of judicious errors associated with branch-length calculations and calibration points. Bayesian inference indicates a very close relationship between the Lake Eg[caron]irdir and Ponto-Caspian taxa. Parametric bootstrapping rejects the null hypothesis that these taxa are not monophyletic (P The present study shows that there is no close biogeographical affiliation between the probably only remaining endemic taxon of Lake Eg[caron]irdir and taxa from central Europe or the Balkan region. Instead, there is a very close and relatively young (i.e. late Pleistocene) biogeographical relationship with the Ponto-Caspian pyrgulinids. However, fossil and comparative data from other invertebrates indicate that biogeographical connections between Lake Eg[caron]irdir and the Ponto-Caspian region existed during various time periods, i.e. the Miocene/Pliocene, early Pleistocene, and late Pleistocene. Acknowledging the still-restricted knowledge of the evolutionary history of the lake, the data presented here do not reject the putative ancient status of Lake Eg[caron]irdir. Future studies utilizing endemic taxa of other lakes in the region need to show whether the western Taurus Lake District represents a melting pot of Pleistocene refuge biodiversity from different regions, and whether the admixture of divergent lineages has created a genetically distinct set of taxa that would warrant the designation of the area as a unique biogeographical subregion.