Meeting Abstract

33-1  Thursday, Jan. 5 13:30 - 13:45  Delineation of Capitella Species (Annelida: Capitellidae) in the Northern Gulf of Mexico and Floridian Ecoregions HILLIARD, JL*; HAJDUK, MM; SCHULZE, A; Texas A&M University Galveston Campus; Texas A&M University Galveston Campus; Texas A&M University Galveston Campus jhilliard@tamu.edu

Capitella capitata was frequently cited as a cosmopolitan bioindicator due to its occurrence in high densities in disturbed marine environments. However, it is now clear C. capitata is a cryptic species complex on the basis of allozyme and developmental studies. We aimed to assess species boundaries in this complex in the Northern Gulf of Mexico and Floridian Ecoregions using molecular sequence data. We sequenced individuals of C. cf. capitata and C. cf. aciculata (distinguished by acicular spines on the first two chaetigers) collected from Texas and Florida Gulf of Mexico coasts and C. cf. caribaeorum from the species’ type locality in Miami, Florida. These data were analyzed in conjunction with data available in GenBank (Canada and Indo-Pacific waters). Our results indicate the presence of a Gulf of Mexico/Florida clade that is distinct from populations in Canada and the Indo-Pacific. Populations are structured geographically, with support for Texas and Florida clades. Within the Florida clade there is support for Gulf of Mexico and Miami (C. cf. caribaeorum) clades. There are no clear boundaries between C. cf. capitata and C. cf. aciculata within the Texas and Gulf of Mexico Florida clades. This is corroborated by the fact that multiple specimens were morphologically intermediate between the two species. Future efforts will be focused on understanding the relationships between these three putative species in the Northern Gulf of Mexico and Floridian Ecoregions.