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Type: Articles
Published: 2006-01-30
Page range: 43–56
Abstract views: 54
PDF downloaded: 3

A new species of freshwater mussel (Bivalvia: Unionidae), Pleurobema athearni, from the Coosa River Drainage of Alabama, USA

Department of Biological Sciences, Auburn University, Auburn Alabama 36849, USA
U.S. Geological Survey, 7920 NW 71st Street, Gainesville, Florida 32653, USA
Department of Biological Sciences, Auburn University, Auburn Alabama 36849, USA
Mollusca Big Canoe Creek freshwater mussel Mobile Basin mollusk biodiversity Unionoida endemic species


The Mobile Basin historically supported one of the most diverse freshwater mussel (Bivalvia: Unionidae) assemblages in North America. More than 65 species of mussels are known from the Basin, but it is difficult to determine how many species were present historically. The drainage's unique physical habitat was largely destroyed between the late 1800s and mid-1900s by impoundment and channel modifications of most of the larger rivers. Many species that were once common are now restricted to small headwater rivers and mid-sized tributaries. Recent Coosa River tributary surveys revealed a new, undescribed species of Pleurobema. This new species, Pleurobema athearni, is distinctive in outward appearance, shell morphometry and reproductive morphology, and can be distinguished from other Coosa River drainage unionids. Our analysis indicates that P. athearni is morphologically different from other similar taxa. It differs both in shell width/length and width/height ratios and thus provides a simple, quantitative means to differentiate this species from P. georgianum (Lea, 1841) Fusconaia barnesiana (Lea, 1838), and F. cerina (Conrad, 1838), which it superficially resembles and that also occur in the area. Our morphological diagnosis of this species is supported by recent molecular analyses that suggest this species is a Pleurobema and one closely related to other endemic Coosa River drainage unionids. The discovery of a new species of large, long-lived macroinvertebrate from a relatively well-sampled drainage in a populated region of the southeast United States underscores the need for more detailed surveys in isolated stretches of tributary streams. It should also serve as a reminder that almost 40 species of aquatic mollusks have been extirpated from the Mobile Basin before anything could be learned about their habitat or life history requirements.


  1. Berg, D.J. & Berg P.H. (2000) Conservation genetics of freshwater mussels: comments on Mulvey et al. Conservation Biology, 14, 1920–1923.

    Buhay, J.E., Serb, J.M., Dean, C.R., Parham, Q., & Lydeard, C. (2002) Conservation genetics of two endangered unionid bivalve species, Epioblasma florentina walkeri and E. capsaeformis (Unionidae: Lampsilini). Journal of Molluscan Studies, 68, 385–391.

    Burch, J.B. (1973) Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Biota of Freshwater Ecosystems Identification Manual 11, U.S. Environmental Protection Agency, Washington, DC, 176 pp.

    Campbell, D.C., Serb, J.M., Buhay, J.E., Roe K.J., Minton R.L., & Lydeard, C. 2005. Phylogeny of North American amblemines (Bivalvia, Unionidae): prodigious polyphyly proves pervasive across genera. Invertebrate Biology, 124, 131–164.

    Clarke, A.H. (1981) The tribe Alasmidontini (Unionidae: Anodontinae), Part I: Pegias, Alasmidonta, and Arcidens. Smithsonian Contributions to Zoology, 326, 1–101.

    Clarke, A.H. (1985) The tribe Alasmidontini (Unionidae: Anodontinae), Part II: Lasmigona and Simpsonaias. Smithsonian Contributions to Zoology, 399, 1–75.

    Evans, R.D. (2001) Historical and contemporary distributions of aquatic mollusks in the Upper Conasauga River system of Georgia and Tennessee. M.S. Thesis, University of Tennessee, Chattanooga, 277 pp.

    Gangloff MM. (2003) The status, physical habitat associations, and parasites of freshwater mussels in the upper Alabama River drainage, Alabama. Ph.D. Dissertation, Auburn University, 237 pp.

    Hurd, J.C. (1974) Systematics and zoogeography of the unionacean mollusks of the Coosa River Drainage of Alabama, Georgia, and Tennessee. Ph.D. Dissertation, Auburn University, Alabama, 240 pp.

    Jones, J.W. (2004) A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the oyster mussel (Epioblasma capsaeformis) and tan riffleshell (Epioblasma florentina walkeri) (Bivalvia: Unionidae). M.S. Thesis, Virginia Polytechnic Institute and State University, Blacksburg, 191 pp.

    Kallersjo, M., von Proschwitz, T., Lundberg, S., Eldenas, P., & Erseus C. (2005) Evaluation of ITS rDNA as a complement to mitochondrial gene sequences for phylogenetic studies in freshwater mussels: an example using Unionidae from north-western Europe. Zoologica Scripta, 34, 415–424.

    King, T.L., Eackles, M.S., Gjetvaj, B., & Hoeh, W.R. (1999) Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): conservation implications of range discontinuity. Molecular Ecology, 8, S65–S78.

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

    Lydeard, C., Garner, J.T., Hartfield, P. & Williams, J.D. (1999) Freshwater mussels in the Gulf Region: Alabama. Gulf of Mexico Science, 1999, 125–134.

    Lydeard, C. & Mayden, R.L. (1995) A diverse and endangered aquatic ecosystem of the southeast United States. Conservation Biology, 9, 800–805.

    McGregor, S.W., ONeil, P.E. & Pierson, J.M. (2000) Status of the freshwater mussel (Bivalvia: Unionidae) fauna in the Cahaba River system, Alabama. Walkerana, 11, 215–238.

    Mirarchi, R.E. (Ed.) (2004) Alabama wildlife. Volume 1. A checklist of vertebrates and selected invertebrates: Aquatic mollusks, fishes, amphibians, reptiles, birds, and mammals. The University of Alabama Press, Tuscaloosa, 209 pp.

    Mulvey, M., Lydeard, C., Pyer, D.L., Hicks, K.M., Brim-Box, J., & Williams, J.D. (1997) Conservation genetics of North American freshwater mussels Amblema and Megalonaias. Conservation Biology, 11, 868–878.

    Neves, R.J., Bogan, A.E., Williams, J.D., Ahlstedt, S.A. & Hartfield, P.W. (1997) Status of aquatic mollusks in the southeastern United States: a downward spiral of diversity. In: Benz, G.W. & Collins, D.E. (Eds.), Aquatic fauna in peril; the southeastern perspective. Special Publication 1, Southeast Aquatic Research Institute, Lenz Design and Communications, Decatur, Georgia, pp. 43–86.

    Ortmann, A.E. (1920) Correlation of shape and station in freshwater mussels (naiades). Proceedings of the American Philosophical Society 59, 269–312.

    Ortmann, A.E. (1923) The anatomy and taxonomy of certain Unioninae and Anodontinae from the Gulf Drainage. The Nautilus, 26, 73–144.

    Parmalee, P.W. & Bogan, A.E. (1998) The freshwater mussels of Tennessee. University of Tennessee Press, Knoxville, 328 pp.

    Roe, K.J., Hartfield, P.D. & Lydeard C. (2001) Phylogenetic analysis of the threatened and endangered superconglutinate-producing mussels of the genus Lampsilis (Bivalvia: Unionidae). Molecular Ecology, 10, 2225–2234.

    Roe, K.J. & Hoeh, W.R. (2003) Systematics of freshwater mussels (Bivalvia: Unionoida) In: Lydeard, C. & Lindberg, D.R. (Eds.), Molecular Systematics and Phylogeography of Mollusks, Smithsonian Books, Washington DC, pp. 91–122.

    Simpson, C.T. (1914) A descriptive catalogue of the naiades, or pearly freshwater mussels. Bryant Walker, Detroit, 1540 pp.

    Sokal, R.R. & Rohlf, F.J. (1995) Biometry, third edition. W. H. Freeman, New York. 887 pp.

    Turgeon, D.D., Quinn, Jr., J.F., Bogan, A.E., Coan, E.V., Hochenberg, F.G., Lyons, W.G., Mikkelsen, P.M., Neves, R.J., Roper, C.F.E., Rosenberg, G., Roth, B., Scheltema, A., Thompson, F.G., Vecchione, M. & Williams, J.D. (1998) Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks, second edition. American Fisheries Society, Special Publication 26, Bethesda, Maryland, 526 pp.

    U.S. Fish and Wildlife Service (1989) Five Tombigbee River mussels recovery plan. Atlanta, Georgia, 18 pp.

    U.S. Fish and Wildlife Service (2000) Mobile basin aquatic ecosystem recovery plan. Atlanta, Georgia, 128 pp.

    Walker, B. (1918) A synopsis of the classification of the freshwater Mollusca of North America, north of Mexico and a catalogue of the more recently described species, with notes. University of Michigan Museum of Zoology Miscellaneous Publications 6, 213 pp.

    Williams, J.D, Fuller, S.L.H. & Grace, R. (1992) Effects of impoundments on freshwater mussels (Mollusca: Bivalvia: Unionidae) in the main channel of the Black Warrior and Tombigbee rivers in western Alabama. Bulletin of the Alabama Museum of Natural History, 13, 1–10.