Meeting Abstract

30.3  Friday, Jan. 4  Molecular Phylogenetics of Forcipulate Starfish (Echinodermata) MAH, Christopher*; FOLTZ, David ; NMNH Smithsonian Inst.; Louisiana State Univ. mahch@si.edu

The Forcipulatacea is one of three major lineages of crown-group Asteroidea. Forcipulates occur in cold-temperate water settings at depths ranging from the intertidal (eg Pisaster) to the abyss(eg Freyella).Polar faunas are particularly diverse.Although forcipulates are morphologically distinctive, classification especially within the Asteriidae has been historically problematic.12 and 16S sequence data was sampled & sequenced from 50 taxa representing the Asteriidae, Pedicellasteridae, Labidiasteridae, Pycnopodiidae, Heliasteridae, Zoroasteridae,and the Brisingida & were analyzed using Bayesian & parsimony analyses resulting in largely similar tree topologies. The tree is strongly tied with regional diversification. A derived lineage composed of individual Holarctic, Antarctic & tropical equatorial clades is supported as a sister group to more basal members which occur primarily in the southern hemisphere and in the deep-sea. Zoroasterids and brisingids are supported as monophyletic although exact relationships between these and other basal forcipulataceans is more ambiguous. The Labidiasteridae, which has long been perceived as artificial is polyphyletic & should be synonymized. The Pedicellasteridae, which has been perceived as intermediate between forcipulates & other asteroids is also not supported as monophyletic. Basal forcipulates are morphologically most similar to Jurassic fossils. Asteriid diversification events are consistent with historical events such as the glaciation of Antarctica. Brooding is observed only from the Antarctic and Holarctic lineages on distantly related clades.Depth, biogeography and larval nutrition (planktotrophy vs lecithotrophy) were also mapped onto the tree and will be discussed. Offshore-onshore trends are supported.