Freshwater Molluscan Shells: Pulmonata
The Lymnaeidae are cosmopolitan, with members on all continents and large islands, and even some smaller oceanic islands. Most, in the subfamily Lymnaeinae, are dextral pond snails, while those in the subfamily Lancinae are limpet-like. Burch lists 57 species in nine genera for North America. In common with other freshwater pulmonates, all feed on algae and detritus, and all are hermaphroditic. Species are fewer and smaller in the tropics, where they may carry parasites including trematodes and flukes.
Burch, (1982) uses the following classification for North American Lymnaeids:
Genus Fossaria, with subgenera Fossaria ss., and Bakerilymnaea
Genus Stagnicola, with subgenera Stagnicola ss., and Hinkleyia
Subfamily Lancinae (all limpet-like; see Freshwater limpets)
Genus Lanx, with subgenera Lanx ss, and Walkerola
Bulimnea megasoma (Say, 1824) North-central United States and adjacent Canada, shallow water, smaller lakes.
These two species are commonly found
crawling on mud and debris, just above the
waterline of ponds or slow-moving creeks.
Fossaria obrussa Say, 1825. Southeastern United States.
Pseudosuccinea columela (Say, 1817)
Eastern North America
(Say, 1821) Much of the
U. S. and Canada.
Stagnicola caperata (Say,
1829) Northern North America.
Eastern Canada and Northeast U.S.
Lymnaea peregra (Muller, 1774)
Europe. Halstead's Golden Guide to
Tropical Fish indicates this species
should be avoided in aquaria because
it produces a poison fatal to fish.
Lymnaea stagnalis (Linne, 1758) Europe, also North America.
Lymnaea (Stagnicola) fuscus (C. Pfeiffer, 1821) from Bulgaria
(left) and Lymnaea palustris (Muller, 1774), from Kazakhstan (right).
Identifications provided by Richard Ottermans. Both x2.
Lymnaea luteola australis Annandale & Rao,
1925. Sri Lanka. x3.
1822) Farm ponds,
Austropeplea lessoni (Deshayes, 1830) New South Wales,
Lymnaea (Radix) natalensis Krauss, 1848
South Africa. Image from Pilsbry and Bequaert, 1927,
courtesy American Museum of Natural History
Many lymnaeid snails are adapted to marginal and ephemeral habitats. The photos above show a thriving population in the American Mid-South which was present only because of unusually wet weather that year.