Phylogenetic relationships of the genus Aphanius (Cyprinodontidae) in southern and south-western Iran

Plate tectonics and geological activities have strongly influenced the presentlandscape of the Iranian plateau since the closure of the Tethys about 23 Ma ago.However, the influence of these geological events has not been fully explored withregard to the diversification of Iranian freshwater fishes. This is particularlyinteresting with regard to the Iranian inland species of Aphanius (Nardo, 1827)(Cyprinodontidae), currently represented by ten endemic species that have beenformally described or going to be described. This diversification is particularly highin south and south-western parts of Iran. This study uses mt-DNA sequence data andvarious morphological data to explore the phylogenetic relationships between theAphanius species in these regions. The results showed that the first split of Aphaniuspopulations probably happened > 10 m.y. ago within the Iranian inland Aphaniusspecies. This split led to the divergence of the present-day Aphanius vladykovi andan ancient clade. It is followed by the divergence of the present-day A. darabensis,A. shirini and A. isfahanensis from the remaining ancient A. farsicus clade by 5 m.y.ago. A final diversification represented by star like radiation took place during theQuaternary and led to the divergence of four additional endemic species i.e. A.sophiae, A. pluristriatus, A. arakensis and A. kavirensis. These species arecharacterized by conservatism in external morphology, while a clear differences inmt-DNA sequences and otolith morphology. These patterns are probably linked tothe similarity of the individual environments and intra-species communication, apartfrom the vicariance events. We further conclude that the close phylogeneticrelationships among the recent species may resulted by interconnection of thesespecies during the last glacial maximum of the late Pleistocene (18000-21000 y. BP)and remained so until the sea-level rise of the Early Holocene (11000 y. BP).

Keywords:

Cyprinodontidae , Biodiversity , Zagros Mountains