Meeting Abstract
102.1 Saturday, Jan. 7 Molecular and Morphological Variation in the Barnacle Predator Nemertopsis bivitatta (Nemertea, Hoplonemertea) CAPLINS, S. A.; NORENBURG, J. L.; TURBEVILLE, J. M.*; Virginia Commonwealth University, Richmond, VA; National Museum of Natural History, Washington, DC; Virginia Commonwealth University, Richmond, VA jmturbeville@vcu.edu
The nemertean Nemertopsis bivitatta is a suctorial barnacle feeder abundant in hard-bottom intertidal communities along the coasts of Europe, South America, and the Southeastern United States. Individuals of N. bivitatta are typically pale yellow to whitish in color with a pair of dorsally-situated dark greenish brown pigment bands that extend for nearly the entire length of the worm. In most individuals these stripes are separated anteriorly, but in some a transverse pigment bar connects them anteriorly. Variation in stripe configuration has been considered to reflect intraspecific variation. We sampled a population containing both morphs from Pawleys Island, SC, USA to assess the extent of variation at the morphological and molecular level. Our qualitative analysis of stylet basis morphology for 20 individuals of each morph revealed morph-specific variation; morphometric analyses are planned to quantify the differences. We sequenced the mitochondrial cytochrome-oxidase one gene (cox1, 500-650 bps) for 8 individuals exhibiting the anterior fusion of pigment bands and for 14 individuals without this feature. Sequences for the two morphs are mutually exclusive, with a minimum and an a maximum pair-wise difference of 13.6% and 19.9.%, respectively (average 15.8%). This lies within the range of variation observed between valid species in Hoplonemertea. A tree-based species delimitation analysis is consistent with sequence divergence and morphological data, placing the morphs in separate lineages with strong support. These preliminary findings suggest that the morphs represent separate species, and we are currently analyzing the nuclear gene fragment ITS2 to provide a more rigorous delimitation test.
