Mytella charruana (d'Orbigny, 1846) Charrua Mussel

    Collected intertidally attached to wooden pole in the surf during a minus tide, Mayport Naval Station Beach at periphery of Hanna Park, Duval County, Florida 1/22/2007 (21 mm.)

    This particular morph is thicker-shelled, darker, more narrow, curved, and capacious than the Mytella charruana taken from lower salinity habitats. It is probably referable to M. arciformis (Dall, 1909) named from Huaquilla, Ecuador. This taxon was considered synonymous with the Charrua Mussel (Soot-Ryen, 1955), but Olsson (1961) treated the two as separate species. It is not unlikely that the two are ecophenotypic morphs of the same species both here and in the Panamic Province, where both appear to be native (Keen, 1971). Molecular analysis may shed light on this taxonomic issue.

Keen, A. M., 1971. Sea shells of tropical west America. Stanford Univ. Press, CA, pp. 1-1064 incl. numerous figs. + 22 pls.

Olsson, A. A., 1961. Mollusks of the tropical eastern Pacific, particularly from the southern half of the Panamic-Pacific faunal province (Panama to Peru). Panamic-Pacific Pelecypoda. Paleontological Research Institution, Ithaca, NY. 574  pp. + 86 pls. Mar. 10.

Soot-Ryen, T., 1955.  A report on the family Mytilidae (Pelecypoda). Allan Hancock Expeditions 20(1): 1-174 (incl. 78 text figs) + 10 pls. Nov. 10.