Dillon 2006

Dillon RT. 2006. The classification of the Lymnaeidae. Letter to the FWGNA project group, December 2006. http://www.cofc.edu/~fwgna/archive/28Dec06.html.

This article describes the current taxonomic uncertainty of the freshwater gastropod family Lymnaeidae, with reference to the major monographs and taxonomic works of the 20th century.

Baker (1911) describes 113 species and subspecies of Lymnaeidae in North America, including seven genera (one of which is only known from fossils). Later work, including aspects of the Modern Synthesis emphasized the considerable intraspecific morphological variation of this and other families of freshwater snails, leading to a major revision of the family by Hubendick (1951), a monograph that this author refers to as a “masterpiece”.

Hubendick (1951) reduced the family to two genera, with most species placed in Lymnaea; only the “weirdo” limpet-like species of genus Lanx remain separate. Approximately 12 species were recognized for North America, either as endemics or holarctic.

Later work, for example by Burch (1980, 1982), did not adopt Hubendick’s (1951) scheme, resulting in a compromise taxonomic scheme somewhere between that of Hubendick (1951) and Baker (1911). This author proposes a modified scheme for current workers, listing two genera (as Hubendick, 1951), and reducing most of Baker’s (1911) genera to subgenus level, to preserve the utility of such terms as “fossarine” and “stagnicoline” as descriptors of groups of species.

I have assembled a taxonomy of the Lymnaeidae for North America from this letter and from Clarke (1973).