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Southwest Florida Shells with Emphasis on Sanibel & Captiva

By José H. Leal

Family Gastrochaenidae

Rocellaria stimpsonii

(Tryon, 1861)

Stimpson Chimney Clam

Shell size to 18 mm ; shell very thin, oval, inflated. Posterior extremity rounded. Antero-dorsal extremity widely open, gaping. Umbo in anterior position. Color translucent-white. Individuals of Rocellaria stimpsoni bore into calcareous substrates such as coral and shells, where they form bottle-shaped dwellings lined with calcium carbonate. The siphonal tubes in the dwellings are ornamented internally with prongs and carinae. Found locally in, among other structures, valves of Noetia ponderosa, Arcinella cornuta, Chama spp., other bivalves, and occasionally in gastropod shells. In some extreme cases, the bivalve will form dwellings independent of a host structure, agglutinating small bits of shells and other debris (see two photos on right, specimen collected by Amy Tripp.)