Freshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a non-marine or freshwater habitat. The majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, other groups need to come up to the surface of the water in order to take in air to breathe.
The total number of Recent species of freshwater gastropods is about 4,000 (3,795-3,972).[1]
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Taxonomy
The following cladogram is an overview of the main clades of gastropods,[2] with families that contain freshwater species marked in boldface:[1] (Some of these highlighted families consist entirely of freshwater species, but some of them also contain, or even mainly consist of, marine species.)
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Neritimorpha
Note: The numbers of species quoted in this overview refer to extant species only, in other words, extinct fossil species are not counted here.
- Neritiliidae, 5 freshwater species[1]
- Neritidae, largely confined to the tropics, also the rivers of Europe, family includes the marine "nerites".[3] There are about 110 freshwater species.[1]
Caenogastropoda
These are freshwater snails with a gill and an operculum. In freshwater habitats there are ten major families, as well as other families of lesser importance:
- Architaenioglossa
- Ampullariidae, an exclusively freshwater family that is largely tropical and includes the large "apple snails" kept in aquaria.[3] 105-170 species.[1]
- Viviparidae, medium to large snails, live-bearing, commonly referred to as "mystery snails". World wide except South America, and everywhere confined to fresh waters.[3] 125-150 species.[1]
Family Ampullariidae, Pomacea bridgesii.
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Family Viviparidae, Viviparus viviparus.
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- Sorbeoconcha
- Melanopsidae, family native to rivers draining to the Mediterranean, also Middle East, and some South Pacific islands.[3] About 25-50 species.[1]
- Pachychilidae - 165-225 species.[1] native to South and Central America. Formerly included with the Pleuroceridae by many authors.
- Paludomidae - about 100 species in south Asia, diverse in African Lakes, and Sri Lanka.[1] Formerly classified with the Pleuroceridae by some authors.
- Pleuroceridae, abundant and diverse in eastern North America, largely high-spired snails of small to large size.[3] About 200 species[1]
- Semisulcospiridae, - primarily eastern Asia, Japan, also the Juga snails of northwestern North America. Formerly included with the Pleuroceridae.
- Thiaridae, high-spired parthenogenic snails of the tropics, includes those referred to as "trumpet snails" in aquaria.[3] 135 species.[1]
Family Pleuroceridae, Io fluvialis.
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Family Semisulcospiridae, Semisulcospira kurodai.
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Family Thiaridae, Melanoides tuberculatus.
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- Littorinimorpha
- Littorinidae - 2 species in the genus Cremnoconchus are freshwater living in waterfalls.[1] Other species are marine.
- Amnicolidae - about 200 species.[1]
- Assimineidae - about 20 freshwater species,[1] other are marine
- Bithyniidae, small snails, native to Eastern Hemisphere.[3] About 130 species.[1]
- Cochliopidae - 246 species.[1]
- Helicostoidae, the only species Helicostoa sinensis lives in China.[1]
- Hydrobiidae, small to very small snails found world wide.[3] About 1250 freshwater species[1] other are marine.
- Lithoglyphidae - about 100 species.[1]
- Moitessieriidae - 55 species.[1]
- Pomatiopsidae, small amphibious snails scattered worldwide, most diverse in eastern and Southeast Asia.[3] About 170 species.[1]
- Stenothyridae - about 60 freshwater species,[1] others are marine.
- Neogastropoda
- Buccinidae - 8-10 freshwater species in the genus Clea,[1]native to Southeast Asia. Other Buccinidae are marine.
- Marginellidae - 2 freshwater species in the genus Rivomarginella,[1] native to Southeast Asia. Other Marginellidae are marine.
Heterobranchia
- Lower Heterobranchia
- Glacidorbidae - 20 species.[1]
- Valvatidae, small low-spired snails referred to as "valve snails". 71 species.[1]
- Opisthobranchia, Acochlidiacea
- Acochlidiidae - Four shell-less species.[1]
- Tantulidae - there is only one species[1] which is shell-less Tantulum elegans.
- Strubelliidae - there is only one species [1] which is shell-less Strubellia paradoxa.
- Pulmonata, Basommatophora
Basommatophorans are pulmonate or air-breathing aquatic snails, characterized by having their eyes located at the base of their tentacles, rather than at the tips, as in the true land snails Stylommatophora. The majority of basommatophorans have shells that are thin, translucent, and relatively colorless, and all five freshwater basommatophoran families lack an operculum.
- Chilinidae, small to medium-sized snails confined to temperate and cold South America.[3] About 15 species.[1]
- Latiidae, small limpet-like snails confined to New Zealand.[3] One[1] or three species.
- Acroloxidae - about 40 species.[1]
- Lymnaeidae, found worldwide, but are most numerous in temperate and northern regions.[3] These are the dextral (right-handed) pond snails. About 100 species.
- Planorbidae, "rams horn" snails, with a worldwide distribution.[3] About 250 species.[1]
- Physidae, left-handed (sinistral) "pouch snails", native to Europe, Asia, North America.[3] About 80 species.[1]
Family Lymnaeidae, Lymnaea stagnalis.
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Family Physidae, Physella acuta.
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Family Planorbidae, Planorbarius corneus.
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As human food
Several different snail species are eaten in Asian cuisine, including freshwater species.
Archaeological investigations in Guatemala have revealed that the diet of theMaya of the Classic Period (AD 250-900) included freshwater snails.[4]
Aquarium snails
In the developed world, people encounter freshwater snails most commonly in aquaria along with tropical fish. Species available vary in different parts of the world. In the United States, commonly available species include ramshorn snails such as Planorbella duryi, apple snails such as Pomacea bridgesii and the high-spired thiarid malaysian trumpet snail Melanoides tuberculata.
Parasitology
Freshwater snails are widely known to be hosts in the lifecycles of a variety of human and animal parasites, particularly trematodes or "flukes". Some of these relations for prosobranch snails include Oncomelania in the family Pomatiopsidae as hosts of Schistosoma, and Bithynia, Parafossarulus and Amnicola as hosts of Opisthorchis.[5] Thiara and Semisulcospira may host Paragonimus, and Goniobasis (older term including Elimia, Juga and other small high-spired pleurocerid snails) may host Nanophyetus salmincola.[5] Basommatophoran snails are even more widely infected, with many Biomphalaria (Planorbidae) serving as hosts for Schistosoma mansoni, Fasciolopsis and other parasitic groups.[5] The tiny Bulinus snails are hosts for Schistosoma haematobium.[5] Lymnaeid snails (Lymnaeidae) serve as hosts for Fasciola and the cerceriae causing swimmer's itch.[5]
it is worth pointing out that snail-vectored parasites of humans are also human-born parasites of snails; humans are much more likely to carry exotic diseases over long distances than snails are.
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 1.32 1.33 Strong E. E., Gargominy O., Ponder W. F. & Bouchet P. (2008). "Global Diversity of Gastropods (Gastropoda; Mollusca) in Freshwater". Hydrobiologia 595: 149-166. http://hdl.handle.net/10088/7390 doi:10.1007/s10750-007-9012-6.
- ↑ Bouchet, P. & Rocroi, J.-P. (2005). "Classification and Nomenclator of Gastropod Families". Malacologia 47 (1-2).
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 Banarescu P. (1990). Zoogeography of Fresh Waters, Vol. 1, General Distribution and Dispersal of Freshwater Animals. AULA - Verlag, Weisbaden.
- ↑ (Spanish) Foias, Antonia E. (2000). "Entre la política y economía: Resultados preliminares de las primeras temporadas del Proyecto Arqueológico Motul de San José." (PDF online publication). XIII Simposio de Investigaciones Arqueológicas en Guatemala, 1999 (edited by J.P. Laporte, H. Escobedo, B. Arroyo and A.C. de Suasnávar) (Museo Nacional de Arqueología y Etnología, Guatemala): 771–799. http://www.asociaciontikal.com/pdf/60.99_-_Foias.pdf. Retrieved 2009-03-01., page 777.
- ↑ 5.0 5.1 5.2 5.3 5.4 Chandler A. C. & Read C P. (1961). Introduction to Parasitology. John Wiley and Sons, New York. 822 pp.
Further reading
- Haynes A. (2000). "The distribution of freshwater gastropods on four Vanuatu islands: Espiritu Santo, Pentecost, Éfate and Tanna (South Pacific)". Annales de Limnologie 36(2): 101-111. doi:10.1051/limn/2000006, PDF.