SREL Reprint #2558

A genetic approach to resolving taxonomic ambiguity among Pleurobema (Bivalvia: Unionidae) of the eastern Gulf Coast

Karen L. Kandl1, Hsiu-Ping Liu2, Robert S. Butler3, Walter R. Hoeh4, and Margaret Mulvey5

1University of New Orleans, Department of Biological Sciences, New Orleans, Louisiana 70148 USA
2Southwest Missouri State University, Department of Biology, 901 South National Avenue,
Springfield, Missouri 65804-0095, USA
3United States Fish and Wildlife Service, Asheville Field Office, 160 Zillicoa St.,
Asheville, North Carolina 28801, USA
4Kent State University, Department of Biological Sciences, Kent, Ohio 44242-0001, USA
5Virginia Institute of Marine Science, Department of Environmental Science,
The College of William and Mary, Gloucester Point, VA 23602-1346, USA

Abstract: Freshwater mussels in the genus Pleurobema (Bivalvia: Unionidae) from the eastern Gulf drainages of Florida, Georgia, and Alabama are variable conchologically, and several taxonomic names have been applied to shell phenotypes. Clarification of the species status of these mussels is important because they are recognized as imperiled throughout their range, mainly due to habitat destruction. Allozyme electrophoresis and restriction fragment length polymorphisms (RFLPS) of the nuclear ribosomal array showed little genetic differentiation among samples representing the phenotypes designated P. pyriforme and P. bulbosum. Partial DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 distinguished P. reclusum from P. pyriforme and P. bulbosum. Genetic differentiation was observed between other Pleurobema species, specifically P. strodeanum, P. clava, and P. sintoxia. Genetic evidence indicates that the eastern Gulf Coast Pleurobema (P. pyriforme and P. bulbosum) are a single species, P. pyriforme, with variable shell characteristics. Pleurobema reclusum is different genetically and may represent a distinct valid species. Pleurobema pyriforme is a federally endangered species. Although we hesitate to call P. reclusum a distinct species because we were able to sequence DNA from only one individual, it is distinct genetically from P. pyriforme of the Apalachicola-Chattahoochee-Flint rivers basin and should merit conservation status.

Keywords: Pleurobema, Unionidae, RFLP analysis, allozymes, DNA sequencing, conservation, endangered species

SREL Reprint #2558

Kandl, K. L., H. P. Liu, R. S. Butler, W. R. Hoeh, and M. Mulvey. 2001. A genetic approach to resolving taxonomic ambiguity among Pleurobema (Bivalvia: Unionidae) of the eastern Gulf Coast. Malacologia 43:87-101.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).