Cryptic species of the Eucypris virens species complex (Ostracoda, Crustacea) from Europe have invaded Western Australia

Abstract

Eucypris virens, an ostracod with mixed reproduction and Holarctic distribution, forms a species complex with more than 35 cryptic species in Europe. Here, we analysed COI and LSU DNA sequence data from Western Australian E. virens to distinguish between the possibilities that vicariant processes have led to the formation of Australian E. virens species or that these ostracods have been introduced into Western Australia. Phylogenetic reconstructions, genetic networks and estimates of genetic distances all show clearly that Western Australian and European E. virens are very closely related. Some haplotypes are identical, others are only separated by one or two mutational steps. Among the Western Australian representatives of E. virens, three phylogenetic clades can be distinguished. We identified three European cryptic species as ancestors for two of the Western Australian clades and one close relative to the third Western Australian clade. We therefore conclude that E. virens has been introduced into Western Australia, most likely from western Europe, and did not diverge in Australia. In Europe, E. virens shows a typical pattern of geographic parthenogenesis while we found only asexual populations in Western Australia.