FWGNA > Species Accounts > Planorbidae > Gyraulus parvus
Gyraulus parvus (Say 1817)

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> Habitat & Distribution

Gyraulus parvus populations are widespread in ponds, impoundments, and slow-moving rivers throughout North America, from Canada to Florida, Atlantic to Pacific (Baker, 1928; Clarke, 1981; Thompson, 1999).  They seem best adapted to richer, more permanent, lacustrine environments, and are not typically found in intermittent or temporary waters or swamps.  Gyraulus parvus populations seem to reach maximum densities on floating vegetation, especially underneath the leaves of water lilies in larger lakes and riverine backwaters.  FWGNA incidence rank I-5.

> Ecology & Life History

Gyraulus parvus populations have figured in a variety of ecological studies in northern lakes (Horst & Costa 1971, Sheldon 1987, Osenberg 1989) but are not well studied in the south.  Jokinen (1987) characterized G. parvus as a “C-D tramp” in New England, characteristic of habitats occurring virtually everywhere she sampled. Dillon’s (2000: 360-363) reanalysis of these data suggested that G. parvus populations in Connecticut seem to be Undifferentiated with respect to life history adaptation.

The Canadian population studied by McKillop (1985) displayed a simple annual life cycle (A).  The effect of fish predation on G. parvus populations has been investigated by Martin et al. (1992) and Thorp & Bergey (1981).  The interesting dispersal expriments of Malone (1965), although nominally involving Promenetus, were probably conducted on Gyraulus parvus.  See my essay of 15Dec16 from the link below.

> Taxonomy & Systematics

Originally described in the genus Planorbis, parvus has remained taxonomically stable since its transfer to Gyraulus in the early 20th century.  Dall considered circumstriatus, parvus, and several more obscure taxa sufficiently distinct from other Gyraulus that he proposed a "section" Torquis to contain it, which Baker (1945) considered a subgenus.

The classification of the Planorbidae proposed by the tag team of Baker (1945) and Hubendick (1955) remains, after 50 years, the basis for our understanding of this large and diverse family of pulmonates worldwide.  See my essay of 11Apr08 from the link below for more.

> Supplementary Resources [PDF]

> Essays

> References

Baker, F. (1945) The Molluscan Family Planorbidae. Urbana: University of Illinois Press.  
Baker, H. B. (1946) Index to F.C. Baker's "The Molluscan Family Planorbidae." Nautilus, 59, 127-41. 
Dillon, R. T., Jr. (2000) The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, England. 509 pp.
Horst, T. & R. Costa ( 1971) Distribution patterns of five selected gastropod species from McCargo Lake. Nautilus, 85: 38-43. 
Hubendick, B.  (1955)  Phylogeny in the Planorbidae.  Trans. Zool. Soc. London 28: 453-542.  
Jokinen, E.  (1987)  Structure of freshwater snail communities: species-area relationships and incidence categories. Am. Malacol. Bull., 5: 9-19.
Malone, C. R. (1965) Killdeer (Charadrius vociferus) as a means of dispersal for aquatic gastropods. Ecology 46: 551-552.
Martin, T., L. Crowder, C. Dumas, & J. Burkholder (1992) Indirect effects of fish predation on macrophytes in Bays Mountain Lake: Evidence for a littoral trophic cascade. Oecologia, 89: 476-81. 
McKillop, W. (1985) Distribution of aquatic gastropods across the Ordovician dolomite – Precambrian granite contact in southeastern Manitoba. Can. J. Zool., 63: 278-88. 
Osenberg, C. (1989) Resource limitation, competition and the influence of life history in a freshwater snail community. Oecologia, 79: 512-19. 
Sheldon, S, P. (1987) The effects of herbivorous snails on submerged communities in Minnesota lakes. Ecology, 68: 1920-31. 
Thorpe, J. & E. Bergey (1981) Field experiments on responses of a freshwater benthic macroinvertebrate community to vertebrate predators. Ecology, 62: 365-75.