Biomphalaria
Encyclopedia
Biomphalaria is a genus
of air-breathing freshwater snail
s, aquatic
pulmonate gastropod mollusks in the family
Planorbidae, the ram's horn snail
s and their allies.
Biomphalaria is the type genus
of the tribe Biomphalariini.
Taphius is a synonym for Biomphalaria.
The shell of this species, like all planorbids is sinistral in coiling, but is carried upside down and thus appears to be dextral.
There are 22 American species:
There are 12 species in the Old World
(Africa, Madagacar and the Middle East):
There is one known hybrid Biomphalaria glabrata × Biomphalaria alexandrina from Egypt.
A cladogram
showing phylogenic relations of (23 analyzed) species in the genus Biomphalaria:
colonized Africa 2.3–4.5 or 2-5 millions years ago and speciated
into all the African Biomphalaria species.
Natural populations of these snails are usually found in tropical standing water or freshwater in South America
and Africa
, but they also reach 30° latitude in subtropical areas. Many species of these red-blooded planorbid snails (Gastropoda: Basommatophora) are able to survive a long time when removed from their freshwater habitat. Of the 34 Biomphalaria species, 4 (Biomphalaria glabrata
, Biomphalaria pfeifferi
, Biomphalaria straminea
, and Biomphalaria tenagophila
) have recently expanded their native ranges. They have been introduced to areas where other Biomphalaria species are endemic (e.g., Congo and Egypt) or to subtropical zones that have no frost period (Texas, Louisiana, Florida, Hong Kong).
All species in the genus Biomphalaria except of native Biomphalaria obstructa has not yet become established in the USA, but they are considered to represent a potentially serious threat as a pest, an invasive species
which could negatively effect agriculture, natural ecosystems, human health or commerce. Therefore it has been suggested that this species be given top national quarantine
significance in the USA.
(vector) for the human parasitic blood fluke, Schistosoma mansoni
, that infects about 83 million people.
The human disease schistosomiasis
caused by all Schistosoma
species (transmitted also by other snails) infects 200 million people. The fluke, which is found primarily in tropical areas, infects mammals (including humans) via contact with water that contains schistosome larvae (cercariae) which have previously been released from the snail. Infection occurs via penetration of cercariae through the skin.
Eighteen species of Biomphalaria are intermediate hosts for Schistosoma mansoni; seven species of the genus have not been tested for this susceptibility and nine species are resistant.
Altogether about 30 species of parasites from Africa and at least 20 species from the Neotropics are known to parasitize Biomphalaria.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of air-breathing freshwater snail
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 watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....
s, aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
pulmonate gastropod mollusks in the family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
Planorbidae, the ram's horn snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s and their allies.
Biomphalaria is the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
of the tribe Biomphalariini.
Taphius is a synonym for Biomphalaria.
The shell of this species, like all planorbids is sinistral in coiling, but is carried upside down and thus appears to be dextral.
Species
There are 34 species in the genus Biomphalaria in total.There are 22 American species:
- Biomphalaria amazonica Paraense, 1966
- Biomphalaria andecolaBiomphalaria andecolaBiomphalaria andecola is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(d'Orbigny, 1835) - Biomphalaria cousini
- Biomphalaria edisoni Estrada, Velásquez, Caldeira, Bejarano, Rojas & Carvalho, 2006
- Biomphalaria glabrataBiomphalaria glabrataBiomphalaria glabrata is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(Say, 1818) - Biomphalaria havanensisBiomphalaria havanensisBiomphalaria havanensis, common name the ghost rams-horn, is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(L. Pfeiffer, 1839) - Biomphalaria helophila (d'Orbigny, 1835)
- Biomphalaria intermedia (Paraense & Deslandes, 1962)
- Biomphalaria kuhnianaBiomphalaria kuhnianaBiomphalaria andecola is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.- Shell description :All species within the family Planorbidae have sinistral shells....
(Clessin, 1883) - Biomphalaria obstructa
- Biomphalaria occidentalis Paraense, 1981
- Biomphalaria oligoza Paraense, 1974
- Biomphalaria orbignyi Paraense, 1975
- Biomphalaria peregrinaBiomphalaria peregrinaBiomphalaria peregrina is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(d'Orbigny, 1835) - Biomphalaria prona
- Biomphalaria schrammi (Crosse, 1864)
- Biomphalaria stramineaBiomphalaria stramineaBiomphalaria straminea is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(Dunker, 1848) - Biomphalaria subprona (Martens, 1899) - http://www.scielo.br/scielo.php?pid=S0074-02761996000200011&script=sci_arttext
- Biomphalaria temascalensis Rangel-Ruiz, 1987
- Biomphalaria tenagophilaBiomphalaria tenagophilaBiomphalaria tenagophila is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
(d'Orbigny, 1835)
There are 12 species in the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
(Africa, Madagacar and the Middle East):
- Biomphalaria alexandrinaBiomphalaria alexandrinaBiomphalaria alexandrina is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails and their allies.- Habitat :...
- Biomphalaria angulosaBiomphalaria angulosaBiomphalaria angulosa is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This species is found in Malawi, Tanzania, and Zambia....
Mandahl-Barth, 1957 - Biomphalaria barthiBiomphalaria barthiBiomphalaria barthi is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This species is endemic to Ethiopia....
Brown, 1973 - Biomphalaria camerunensis
- Biomphalaria choanomphala
- Biomphalaria pfeifferiBiomphalaria pfeifferiBiomphalaria pfeifferi is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This snail is a medically important pest, because of transferring the disease schistosomiasis....
(Krauss, 1848) - Biomphalaria salinarumBiomphalaria salinarumBiomphalaria salinarum is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This species is found in Angola and Namibia....
Morelet - Biomphalaria smithiBiomphalaria smithiBiomphalaria smithi is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.Biomphalaria smithi is the type species of the genus Biomphalaria...
Preston, 1910 - type species - Biomphalaria stanleyiBiomphalaria stanleyiBiomphalaria stanleyi is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.- Distribution :This species is African, and occurs in:* Lake Albert, Uganda...
(Smith, 1888) - Biomphalaria sudanicaBiomphalaria sudanicaBiomphalaria sudanica is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.- Distribution :This species is African, and occurs mainly in East Africa:...
(Martens, 1870) - Biomphalaria tchadiensisBiomphalaria tchadiensisBiomphalaria tchadiensis is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This species is endemic to lake Chad in Cameroon, Chad and in Nigeria....
Germain, 1904 - Biomphalaria ruppellii Auet. - subspecies: Biomphalaria ruppellii ruppellii Auet.; Biomphalaria ruppellii katangae Haas
There is one known hybrid Biomphalaria glabrata × Biomphalaria alexandrina from Egypt.
A cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
showing phylogenic relations of (23 analyzed) species in the genus Biomphalaria:
Distribution
The origin of the genus Biomphalaria is American. The ancestor of Biomphalaria glabrataBiomphalaria glabrata
Biomphalaria glabrata is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
colonized Africa 2.3–4.5 or 2-5 millions years ago and speciated
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
into all the African Biomphalaria species.
Natural populations of these snails are usually found in tropical standing water or freshwater in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, but they also reach 30° latitude in subtropical areas. Many species of these red-blooded planorbid snails (Gastropoda: Basommatophora) are able to survive a long time when removed from their freshwater habitat. Of the 34 Biomphalaria species, 4 (Biomphalaria glabrata
Biomphalaria glabrata
Biomphalaria glabrata is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
, Biomphalaria pfeifferi
Biomphalaria pfeifferi
Biomphalaria pfeifferi is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.This snail is a medically important pest, because of transferring the disease schistosomiasis....
, Biomphalaria straminea
Biomphalaria straminea
Biomphalaria straminea is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
, and Biomphalaria tenagophila
Biomphalaria tenagophila
Biomphalaria tenagophila is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
) have recently expanded their native ranges. They have been introduced to areas where other Biomphalaria species are endemic (e.g., Congo and Egypt) or to subtropical zones that have no frost period (Texas, Louisiana, Florida, Hong Kong).
All species in the genus Biomphalaria except of native Biomphalaria obstructa has not yet become established in the USA, but they are considered to represent a potentially serious threat as a pest, an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
which could negatively effect agriculture, natural ecosystems, human health or commerce. Therefore it has been suggested that this species be given top national quarantine
Quarantine
Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....
significance in the USA.
Parasites
This genus of snails is medically important, because the snails can carry a parasite of humans which represents a serious disease risk: the snails serve as an intermediate hostIntermediate host
A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary host...
(vector) for the human parasitic blood fluke, Schistosoma mansoni
Schistosoma mansoni
Schistosoma mansoni is a significant parasite of humans, a trematode that is one of the major agents of the disease schistosomiasis. The schistosomiasis caused by Schistosoma mansoni is intestinal schistosomiasis....
, that infects about 83 million people.
The human disease schistosomiasis
Schistosomiasis
Schistosomiasis is a parasitic disease caused by several species of trematodes , a parasitic worm of the genus Schistosoma. Snails often act as an intermediary agent for the infectious diseases until a new human host is found...
caused by all Schistosoma
Schistosoma
A genus of trematodes, Schistosoma, commonly known as blood-flukes and bilharzia, includes flatworms which are responsible for a highly significant parasitic infection of humans by causing the disease schistosomiasis, and are considered by the World Health Organization as the second most...
species (transmitted also by other snails) infects 200 million people. The fluke, which is found primarily in tropical areas, infects mammals (including humans) via contact with water that contains schistosome larvae (cercariae) which have previously been released from the snail. Infection occurs via penetration of cercariae through the skin.
Eighteen species of Biomphalaria are intermediate hosts for Schistosoma mansoni; seven species of the genus have not been tested for this susceptibility and nine species are resistant.
Altogether about 30 species of parasites from Africa and at least 20 species from the Neotropics are known to parasitize Biomphalaria.
Further reading
- Baker F. C. (1945) The molluscan family Planorbidae. Urbana, The University of Illinois Press, page 89 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Departamento de Vigilância Epidemiológica. (2007) Vigilância e controle de moluscos de importância epidemiológica : diretrizes técnicas : Programa de Vigilância e Controle da Esquistossomose (PCE). Ministério da Saúde, Secretaria de Vigilância em Saúde, Departamento de Vigilância Epidemiológica. 2. ed. Brasília : Editora do Ministério da Saúde. 178 pp. ISBN 978-85-334-1438-9. (Surveillance and Control of Mollusks with Epidemiological Importance: technical directives: Schistosomiasis Control and Surveillance Program)
- Chapter: Aquaculture and schistosomiasis. In: Larsson B. (December 1994) Three overviews on environment and aquaculture in the tropics and sub-tropics. ALCOM (Aquaculture for Local Community Development Programme) Field Document No. 27, 52 pp.
- Plam M., Jørgensen A., Kristensen T. K. & Madsen H. (April 2008) "Sympatric Biomphalaria species (Gastropoda: Planorbidae) in Lake Albert, Uganda, show homoplasies in shell morphology". African ZoologyAfrican ZoologyAfrican Zoology is a biannual peer-reviewed scientific journal that covers any aspect of zoology relevant to Africa and its surrounding oceans, seas, and islands. It is published by the Zoological Society of Southern Africa...
43(1): 34-44. .