Molecular phylogeny and phylogeography of the Greek populations of the genus orthometopon (isopoda, oniscidea) based on mitochondrial DNA sequences

Abstract

We infer phylogenetic relationships among isopod species of the genus Orthometopon distributed in the Greek area, comparing partial mitochondrial DNA sequences for cytochrome oxidase I (COI). All phylogenetic analyses produced topologically identical trees that revealed a well-resolved phylogeny. These trees support the monophyly of the genus Orthometopon, and suggest two clades that correspond to separate geographical regions (west and east of the mid-Aegean trench). However, the phylogenetic relationships among Greek populations of Orthometopon spp. are different from the presumed pattern on the basis of morphological evidence. The distinct geographical distribution of the major clades of the phylogenetic tree and its topology suggest a spatial and temporal sequence of phylogenetic separations, which coincide with some major palaeogeographical separations during the geological history of the Aegean Sea. The results stress the need for a reconsideration of the evolutionary history of Orthometopon species, which will help overcome difficulties encountered in classical taxonomy at the species level. © 2008 The Linnean Society of London.