Meeting Abstract
P1.14 Tuesday, Jan. 4 Phylogeography of an abundant marine parasite: are there cryptic species of thorny-headed worms in mole crabs? GOULDING, Tricia*; COHEN, C. Sarah; Romberg Tiburon Center, SFSU; Romberg Tiburon Center, SFSU tc.goulding@yahoo.com
Despite the ecological importance of parasites there is a lack of information on basic issues such as parasite species identity and specificity, especially in marine systems. Acanthocephalans, or thorny-headed worms, are obligate endoparasites that unlike many parasitic helminthes, are not known to engage in any form of asexual reproduction. This difference in reproductive strategy and life history makes thorny-headed worms an interesting comparison to marine trematodes; we expected that the lack of clonal reproduction would result in increased genetic diversity and less spatial partitioning. Mole crabs (Emerita spp.) are an ideal host to examine because they are abundant in sandy beach ecosystems worldwide and are frequently parasitized. We used molecular techniques to examine cryptic diversity, population structure and phylogeography of a marine acanthocephalan known as Profilicollis altmani. We collected over 500 mole crabs from 4 Emerita species from around North America, from which 166 acanthocephalan parasites were analyzed. Genetic divergence between acanthocephalan populations found in the Pacific Ocean, Atlantic Ocean, and Gulf of Mexico was very low, suggesting that there is significant dispersal of this parasite by seabirds that serve as final hosts. The low genetic divergence in COI (0-1.8%) and ITS (0%) sequences also suggests that this acanthocephalan is not a cryptic species complex. This is an interesting contrast to several studies in freshwater acanthocephalans in which several cryptic species were discovered, often with narrow host specificity. The longevity of acanthocephalan eggs and the mobility of hosts this parasite utilizes could contribute to the generalist strategy of this parasite; it would be intriguing to see if other marine acanthocephalans display similar specificity and distribution patterns.
