Meeting Abstract
The family Agelenidae C.L. Koch 1837 is large (70 genera, 1157 species currently described, accounting for about 2.5% of all spider species) with a high level of endemicity in the North America, and California in particular. Spiders from this family have recently been used as models for toxicological and behavioral research. In the Agelenidae, there have been eight genera (Hololena, Rualena, Calilena, Novalena, Agelenopsis, Barronopsis, Tortolena, and Melpomene) classified in the subfamily Ageleninae, tribe Agelenopsini, endemic to North and Central America. In the past year, an additional genus (Rothilena) has been described from Northwestern Mexico. We performed partitioned Bayesian likelihood analysis of molecular sequence data from mitochondrial (CO1 and 16S rDNA) and nuclear (28S rDNA) genes from 25 representative species to develop a phylogenetic hypothesis for these genera. Results support monophyly of a group confined to Western North America extending south into Baja California (Calilena + Hololena + Novalena + Rualena + Rothilena). These are sister to a clade including the primarily Gulf Coast, Caribbean and Atlantic Coast genera Agelenopsis, Barronopsis, and Tortolena. Strong genitalic similarity within the latter group extends to the sole unsequenced genus Melpomene from Eastern Mexico and Central America, consistent with a clear biogeographic split between the Atlantic/Gulf Coast genera and those endemic to the Western US and Mexico. Tree morphology indicates an early period of rapid diversification, though large uncertainty in molecular clock estimates confounded our efforts to rigorously evaluate possible causes of this remarkable continent-wide radiation.
