Meeting Abstract

P1.23  Sunday, Jan. 4  Taxonomy and Evolution of the Chaetogaster limnaei complex (Annelida: Oligochaeta) PATTI, A*; HOCHBERG, R; LITVAITIS, MK; Univ. Massachusetts Lowell; Univ. Massachusetts Lowell; Univ. New Hampshire rick_hochberg@uml.edu

Chaetogaster limnaei is a well-known symbiotic oligochaete that infects freshwater molluscs worldwide. In Massachusetts, the ectosymbiotic subspecies, C.l. limnaei lives in the mantle cavity of freshwater pulmonates where it feeds on single-celled algae, protists and small invertebrates. In some snails, however, the oligochaete lives in the host’s kidney tissue and sustains a parasitic relationship, occasionally ingesting trematode cercariae that also parasitize the host snail. This parasitic form, known as C.l. vaghini, is considered a subspecies of the ectosymbiont despite differing in some morphological and reproductive characteristics. In this investigation, we use molecular sequence data (COI) to determine if these two subspecies are dissimilar at the molecular level. Results indicate that a distinct barcoding gap is present between the two subspecies, and that there is an order of magnitude difference between intra- and interspecific variation. Details on the morphology of both subspecies are presented, as are hypotheses on the potential pathways to parasitism in Chaetogaster.