Meeting Abstract
Pycnogonids, or sea spiders, are marine arthropods with cosmopolitan and eurybathic distribution. Of the approximately 1,300 pycnogonid species described worldwide, over 240 species occur in the Southern Ocean, and over half of those are endemic to the Antarctic. Morphological data suggest circumpolar distributions for multiple Antarctic species; however, recent molecular inquiries into the genetic structure of Antarctic benthic invertebrate populations have revealed varying patterns of genetic connectivity and, in many cases, cryptic speciation events that are incompatible with the previously hypothesized genetic homogeneity for Southern Ocean invertebrates. To date, little is known about genetic connectivity within Antarctic Pallenopsis species populations, and Pallenopsis phylogeny remains highly unresolved, with insufficient morphological data available to determine evolutionary relationships between Pallenopsis and other pycnogonid genera. This study describes genetic structure of Pallenopsis populations of western Antarctic coastal regions, the Scotia Arc, Falkland Islands, and Chilean coast. In this study, we present the results of analyses derived from the mitochondrial COI and 16S rRNA genes that show gene flow patterns between these populations, and provide a molecular basis for phylogenetic assessments of the genus Pallenopsis. Examination of genetic characters in conjunction with traditional morphological taxonomic procedures will provide increased resolution to the evolutionary history of Pallenopsis, and will lead to descriptions of multiple new species. Future sampling and analyses from other areas of the Antarctic coastline will provide a broader context for the phylogeny of Pallenopsis.
