Meeting Abstract

P1.25  Sunday, Jan. 4  A novel peritrich (Ciliophora) from the symbiotic community of freshwater pulmonate snails (Mollusca, Gastropoda) in Massachusetts PATTI, A; HOCHBERG, R*; CLAMP, J; Univ. Massachusetts Lowell; Univ. Massachusetts Lowell; North Carolina Central Univ. rick_hochberg@uml.edu

Freshwater pulmonates are host to numerous symbionts including mutualistic, commensalistic and parasitic protozoans and metazoans. In our investigation of the symbiotic community of two species of freshwater snails, Menetus dilatatus and Physa sp., we discovered a previously undescribed species of peritrich that lives inside the snails pulmonary cavity (lung). We use a combination of brightfield, fluorescence and electron microscopy to describe this new species. This ciliate, a member of the genus Scyphidia, forms colonies on the mantle tissue of small snails with transparent shells. The ciliate is host to endosymbiotic algae (presumably Chlorella) that occupies a large proportion of the ciliates volume and forms a mixotrophic relationship with it. As host snails age, their shells become less transparent, and the colonial ciliate declines in abundance, indicating a potential obligate relationship between the symbionts. Binary fission of the ciliates leads to the production of swarmers that also contain endosymbiotic algae. This report constitutes the first description of mixotrophy in Scyphidia, which comprises both marine and freshwater symbiotic ciliates.