Meeting Abstract
Neopurcellia is a monotypic genus of mite harvestmen endemic to the South Island of New Zealand. These dispersal-limited organisms have a paradoxically widespread distribution given their limited dispersal capabilities, suggestive of multiple cryptic species within the lineage. We analyzed the phylogeography of Neopurcellia salmoni by reconstructing phylogenetic relationships using DNA sequence data from the fast-evolving mitochondrial locus cytochrome c oxidase I (COI). Tree topologies revealed two distinct and well-supported clades occupying non-overlapping geographical regions of the west coast. The strong correlation between the evolutionary relationships of lineages within Neopurcellia and the geographic distribution of its populations indicates that monophyletic groups tend to correspond to similar or adjacent geographic regions, as expected with dispersal-limited organisms. We also used scanning electron microscopy to examine a surprising level of intraspecific variation in the dorsal morphology of these organisms, constituting the first documented case of male polymorphism in the suborder Cyphophthalmi. While the presence of two different morphotypes initially suggested multiple co-distributed Neopurcellia species, the seemingly random geographic and phylogenetic distribution of the male morphotypes allows us to reject this hypothesis. The presence of male polymorphism in Neopurcellia is hypothesized to be the outcome of strong sexual selection, driving the development of alternative reproductive tactics that may improve mating success by enhancing olfaction or chemoreception between glandular males and their mates.
