Meeting Abstract
Opiliones (harvestmen) are the third largest order of arachnids after the Acari (mites and ticks) and Araneae (spiders). Previous work shows that diversification of many groups of Opiliones is closely associated with historical geographic processes. Harvestmen typically have low dispersal capability and high endemicity, and are therefore excellent models for biogeographic studies. Phylogenetic data support Travunioidea as an early-diverging clade within the most diverse suborder of harvestmen, Laniatores. They are short-range endemic taxa distributed in east Asia, North America, and southern Europe. However, the current classification is problematic at higher levels, as it relies heavily on tarsal claw morphology that is argued to be homoplastic. Multilocus phylogenetic data indicate that travunioids are monophyletic and that the Californian genus, Zuma, is nested within a Japanese clade. As part of the SDSU-CAS joint project on species delimitation of Laniatores, homology and variation within this clade were assessed using a standard set of images of both male and female genitalia, as well as somatic morphology, using SEM. Both Japanese and North American travunioids have remained mostly unstudied since the 1970s and were never examined with SEM, which reveals that tarsal claw morphology can vary intraspecifically, and might not be a reliable character for species delimitation. Our morphological analysis will be used to increase confidence in clade support, resulting in phylogeny-based reclassifications of deeper phylogenetic nodes.
