Monday, December 10, 2007 - 8:17 AM

Origins of Synsphyronus (Pseudoscorpiones) diversity on the outcrops of southwestern Australia

Roberta S. Engel, engellaoshi@yahoo.com1, Elizabeth L. Jockusch1, and Mark S. Harvey2. (1) University of Connecticut, Ecology & Evolutionary Biology, 75 N. Eagleville Rd, Unit 3043, Storrs, CT, (2) Western Australian Museum, Department of Terrestrial Invertebrates, James Street, Perth, Western Australia, Australia

Pseudoscorpions are found in a variety of habitats worldwide yet this arachnid order with at least 3300 species remains understudied. The genus Synsphyronus Chamberlin comprises 28 described species found in Australia and New Zealand. One region where this clade’s diversity has not been fully documented is southwestern Australia, an ancient landscape noted for its floristic richness and granite outcrops. The granite outcrops form terrestrial habitat islands, refugia for isolated populations of outcrop-endemic biota including Synsphyronus. S. elegans is the sole described outcrop-endemic in this region, known only from the type locality until recently when two new morphospecies were collected from an outcrop 50 km away. This project aims 1) to characterize the diversity and evolutionary relationships of Synsphyronus endemic to the outcrops in southwestern Australia and 2) to elucidate the evolutionary origins of the outcrop-endemic lineages of Synsphyronus by reconstructing a genus-level molecular phylogeny. Specifically, we are testing the hypothesis that there are multiple origins of outcrop lineages. DNA sequence data provide a useful way to infer relationships as these pseudoscorpions are morphologically cryptic and exhibit high levels of homoplasy. The 70 populations we have sampled sort into five morphospecies, which includes S. elegans. Data from cytochrome oxidase subunit I and the internal transcribed spacer regions indicate that these outcrop taxa are not monophyletic, but instead form four deeply differentiated lineages which largely correspond to four of the morphospecies. These data are consistent with the hypothesis that there have been multiple origins of outcrop lineages in southwestern Australia.

Species 1: Pseudoscorpiones Garypidae Synsphyronus elegans