Phylogeography of cave pseudoscorpions in southern Australia

Abstract

Aim To investigate molecular phylogenetic divergence and historical biogeography of the cave-dwelling pseudoscorpion genus Protochelifer. Location Caves and nearby epigean habitats in southern Australia were sampled from western Victoria, Naracoorte Caves, Flinders Ranges, Kangaroo Island, Nullarbor Plain and south-west Western Australia. Methods Allozyme electrophoresis (57 individuals) and a 569-base-pair section of the mtDNA COI gene (22 individuals) were used to reconstruct phylogenetic relationships among four cave species and three epigean species from 13 locations. Results Phylogenetic reconstruction using the allozyme and mtDNA sequence data revealed a similar topology, showing recent speciation of several Protochelifer populations in caves from Naracoorte to the Nullarbor Plain. Naracoorte Caves contained a single species, Protochelifer naracoortensis, found in four separate caves, while all other cave species appear to be restricted to single caves. Main conclusions At a local scale, as indicated by the four Naracoorte caves, dispersal is thought to occur via micro- and mesocaverns, and possibly by phoresy using insect or bat vectors. With current data we are unable to determine if cavernicolous species of Protochelifer have arisen from a single cave colonization event followed by phoretic dispersal on bats to other caves, or multiple cave-invasion events from independent epigean ancestors. Genetic heterogeneity among Protochelifer populations from Nullarbor caves suggest that P. cavernarum, the only species presently recorded from this region, is likely to constitute a species complex requiring further study to fully resolve its relationships.