Population Genetic Structure and Phylogeography of Mesokalliapseudes macsweenyi (Crustacea: Tanaidacea) in the Northwestern Atlantic and Gulf of Mexico

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Coastal Sciences, Gulf Coast Research Laboratory


Various studies of Gulf of Mexico/Atlantic populations have detected a phylogeographic break created by the Florida peninsula despite the fact that many of these species possess planktonic larvae and/or highly vagile adults. In light of these results, one would predict that the genetic structure in a species with limited dispersal ability would be heavily influenced by the geologic history of this region. Mesokalliapseudes macsweenyi is a direct developing benthic crustacean that occurs in coastal regions of the southeastern United States, ranging from South Carolina to Mississippi. Mitochondrial cytochrome oxidase subunit I (COI) sequences were obtained from 159 specimens representing eight collection sites from across a large portion of its known range to assess the population genetic and phylogeographic structure. Significant genetic structure existed among populations and between the Atlantic/Gulf of Mexico regions, consistent with expectations based on its life history of direct larval development and a sedentary adult stage. Demographic analyses inferred a population expansion in the Gulf of Mexico, which might reflect a Pleistocene post-glacial range expansion. The significant population structure exhibited by the northern Gulf of Mexico populations is likely the product of isolation among populations post expansion, but the diversity of haplotypes might also reflect under-sampled variation or the persistence of individuals in northern refugia during the Pleistocene. Crown Copyright (c) 2011 Published by Elsevier B.V. All rights reserved.

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Journal of Experimental Marine Biology and Ecology



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