FWGNA > Species Accounts > Planorbidae > Menetus dilatatus
Menetus dilatatus (Gould 1841)
“Micromenetus” dilatatus
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> Habitat & Distribution

Menetus dilatatus ranges broadly throughout the eastern US from Florida and Texas into Canada (Baker 1945, B. Bilyj personal communication).  In East Tennessee drainages and U. S. Atlantic drainages (below) it is a common inhabitant of ponds, swamps, and the quiet areas of rivers, especially on vegetation and woody debris.  Menetus dilatatus populations seem to be able to tolerate more acidic water quality, and may be found in darker creeks and swamps in the lowcountry.  FWGNA incidence rank I-5.Click to view larger

> Ecology & Life History

Jokinen (1985) reported three generations per year in a Connecticut population of M. dilatatus, following the D(iss) pattern of Dillon (2000: 156-162).  The data of Jokinen (1983) suggest that populations of the species tend to inhabit poor or peripheral environments in Connecticut.

Jokinen’s (1987) analysis of the distribution of M. dilatatus in Connecticut and New York led her to classify it as a “C-D tramp,” potentially present in nearly every community.  Dillon’s (2000: 360-363) reanalysis of these data suggested that M. dilatatus populations in Connecticut might be S-adapted, common in poor but stable environments, demonstrating low reproductive effort relative to body size.

> Taxonomy & Systematics

Menetus brogniartianus (Lea 1842) and alabamensis (Pilsbry) are synonyms of dilatatus.  Baker (1945) split the H. & A. Adams genus Menetus into a typical subgenus and a subgenus Micromenetus, moving dilatatus, brogniartianus, and three other nominal species into it.  The initiative of Turgeon et al. (1998) to raise Baker's subgenus to the genus level was neither justified nor justifiable.

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.

> Supplementary Resources [PDF]

> Essays 

  • See my post to the FWGNA blog of 11Apr08 for a review of the Classification of the Planorbidae.
  • Or view the (Hubendick 1955) classification of North American planorbids in a tabular format [here].

> References

Baker, F. C. (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, United Kingdom.  509 pp.  
Hubendick, B.  (1955)  Phylogeny in the Planorbidae.  Trans. Zool. Soc. London 28: 453-542.  
Jokinen, E.  (1983)  The freshwater snails of Connecticut. Hartford, Connecticut, State Geol. Nat. Hist. Survey Bull. 109. 83 p.  
Jokinen, E.  (1985)  Comparative life history patterns within a littoral zone snail community. Verh. Internat. Verein, Limnol., 22: 3292-3399. 
Jokinen, E. (1987) Structure of freshwater snail communities: Species-area relationships and incidence categories.  Amer. Malac. Bull. 5: 9 - 19.
Turgeon, D. D. et al. (1998)  Common and Scientific Names of Mollusks, Second edition.  Amer. Fisheries Soc. Sp. Publ. 26.