FWGNA > Species Accounts > Pleuroceridae > Pleurocera laqueata laqueata
Pleurocera laqueata laqueata (Say 1829)
Goniobasis or "Elimia" laqueata

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> Habitat & Distribution

The range of P. laqueata (in its narrow sense) was given by Goodrich (1940) as centered in the Green, Cumberland, and Duck Rivers of central Tennessee and Kentucky, extending into North Alabama.  Our surveys suggest that Pleurocera laqueata populations extend as far east as the Appalachian Plateau tributaries of the Kentucky River, and south down Walden Ridge to the vicinity of Chattanooga.  Throughout this extensive area, P. laqueata populations primarily inhabit rocky riffles in small to moderate-sized rivers and streams.  Considering all subspecies together, its FWGNA incidence rank is I-4.

> Ecology & Life History

Grazing by populations of pleurocerids can have a significant effect on energy flow in small streams (Dillon 2000: 86 - 91, see also Dillon & Davis 1991).

Like other pleurocerids, P. laqueata is dioecious, eggs being deposited on hard substrates from spring to mid-summer.  Eggs are spirally arranged in masses of 2-15 or more, with a tough, membranous outer covering to which sand grains typically adhere (Smith 1980, Jokinen 1992). Although we are unaware of any study specifically directed toward the life history of P. laqueata, it seems reasonable to expect that two years will be required for maturity, and that several years of iteroparous reproduction can be expected thereafter, as is the case for pleurocerids generally (Dazo 1965). This is life cycle Hi of Dillon (2000: 156 - 162).

> Taxonomy & Systematics

This is another North American pleurocerid species demonstrating protean variability in shell morphology, named and re-named dozens of times in the nineteenth and early twentieth centuries.  Goodrich (1940) recognized ten valid species and six valid subspecies in his “group of Goniobasis laqueata,” along with no fewer than 55 synonyms.

More recently it has become clear that the distinction Goodrich and all previous authorities made between the former genera Pleurocera and Goniobasis (or "Elimia") is due to cryptic phenotypic plasticity (Dillon 2011, 2014; Dillon et al. 2013).  This has led to the realization that populations previously identified as "Pleurocera alveare" are likely downstream ecophenotypic morphs of P. laqueata.  See my essays of 23Mar11 and 8Aug18 from the links below for more.

> Supplementary Resources

  • Living Pleurocera laqueata, courtesy of Chris Lukhaup.
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  • Cryptic phenotypic plasticity in P. laqueata. (A) Historic specimen of P. laqueata alveare from Kentucky.  (B) P. laqueata alveare from Dale Hollow Lake, TN.  (C) P. laqueata laqueata from the Duck River, TN.  (D) P. laqueata laqueata from the Nolin River, KY.
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  • > Essays

    > References

    Dazo, B. C.  (1965) The morphology and natural history of Pleurocera acuta and Goniobasis livescens (Gastropoda: Cerithiacea: Pleuroceridae). Malacologia 3: 1 - 80. 
    Dillon, R. T., Jr. (2000)  The Ecology of Freshwater Molluscs. Cambridge, Cambridge University Press.  509 pp. 
    Dillon, R. T., Jr. (2011)  Robust shell phenotype is a local response to stream size in the genus Pleurocera.  Malacologia 53: 265-277.  [pdf]
    Dillon, R. T., Jr.  (2014) Cryptic phenotypic plasticity in populations of the North American freshwater gastropod, Pleurocera semicarinata.  Zoological Studies 53:31. [html] [pdf]
    Dillon, R. T. Jr., & K. B. Davis (1991)  The diatoms ingested by freshwater snails: temporal, spatial, and interspecific variation. Hydrobiologia 210: 233-242. 
    Dillon, R. T., Jr., S. J. Jacquemin & M. Pyron (2013) Cryptic phenotypic plasticity in populations of the freshwater prosobranch snail, Pleurocera canaliculata.  Hydrobiologia 709: 117-127. [html] [pdf]
    Goodrich, C. (1940) The Pleuroceridae of the Ohio River drainage system.  Occas. Pprs. Mus. Zool. Univ. Mich., 417: 1-21.
    Jokinen, E.H. (1992) The freshwater snails of New York State. New York State Museum Biological Survey, New York State Museum Bulletin 482.
    Smith, D.G.  (1980) Goniobasis virginica (Gastropoda: Pleuroceridae) in the Connecticut River USA. Nautilus 94:50-54.