''Biomphalaria'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of air-breathing

freshwater snail Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs t ...

s, aquatic

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

s belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family (biology), family of air-breathing freshwater snails, Aquatic animal, aquatic pulmonate gastropod Mollusca, molluscs. Unlike most molluscs, the blood of ram's horn sn ...

, the ram's horn

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

s and their allies. ''Biomphalaria'' is the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

of the tribe Biomphalariini. Both ''Planorbis'' and ''Taphius'' are synonyms for ''Biomphalaria''. The shell of this species, like all planorbids is left coiling (sinistral), but is carried upside down and thus appears to be right coiling (dextral). Biomphalaria_tenagophila_shell

Species

There are a suspected 35 extant species in the genus ''Biomphalaria'' in total (21 American species and 14 Old World species). However, there are a large number of invalid taxa within the ''Biomphalaria'' literature, which is likely the result of several (if not all) species of ''Biomphalaria'' being subject to various sources of intraspecific variation such as ecophenotypic variation and indeterminate shell growth. This intraspecific variation can make two individuals of the same species appear as two taxonomically distinct entities when identified using only morphological identification methods.

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

(

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

n) species include: # '' Biomphalaria amazonica'' (Paraense, 1966) # '' Biomphalaria andecola'' (d'Orbigny, 1835) # '' Biomphalaria cousini'' (Paraense, 1966) # '' Biomphalaria edisoni'' (Estrada, Velásquez, Caldeira, Bejarano, Rojas & Carvalho, 2006) # ''

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 glabrata'' is an intermediate snail host for the trematode '' S ...

'' (Say, 1818) # '' Biomphalaria havanensis'' (L. Pfeiffer, 1839) # '' Biomphalaria helophila'' (d'Orbigny, 1835) # '' Biomphalaria intermedia'' (Paraense & Deslandes, 1962)Rumi A., Gregoric D. E. G., Núñez V. & Darrigran G. A. (2008). "Malacología Latinoamericana. Moluscos de agua dulce de Argentina". ''

Revista de Biología Tropical The ''Revista de Biología Tropical'' is a bilingual open access scientific journal published by the University of Costa Rica covering research in the field of tropical biology and conservation biology. It was established in 1953. It is indexed and ...

'' 56(1): 77–111
HTM
# '' Biomphalaria kuhniana'' (Clessin, 1883) # † '' Biomphalaria manya'' (Cabrera & Martinez, 2018) # '' Biomphalaria obstructa'' (Morelet, 1849) # ''

Biomphalaria occidentalis ''Biomphalaria'' is a genus of air-breathing freshwater snails, aquatic pulmonates belonging to the family Planorbidae, the ram's horn snails and their allies. ''Biomphalaria'' is the type genus of the tribe Biomphalariini. Both ''Planorbis'' ...

'' (Paraense, 1981) # ''

Biomphalaria oligoza ''Biomphalaria'' is a genus of air-breathing freshwater snails, aquatic pulmonates belonging to the family Planorbidae, the ram's horn snails and their allies. ''Biomphalaria'' is the type genus of the tribe Biomphalariini. Both ''Planorbis'' ...

'' (Paraense, 1974) # '' Biomphalaria orbignyi'' (Paraense, 1975) # '' Biomphalaria peregrina'' (d'Orbigny, 1835) # '' Biomphalaria prona'' (E. von Martens, 1873) # † '' Biomphalaria reversa'' # '' Biomphalaria schrammi'' (Crosse, 1864) # '' Biomphalaria straminea'' (Dunker, 1848) # ''

Biomphalaria subprona ''Biomphalaria'' is a genus of air-breathing freshwater snails, aquatic pulmonates belonging to the family Planorbidae, the ram's horn snails and their allies. ''Biomphalaria'' is the type genus of the tribe Biomphalariini. Both ''Planorbis'' ...

'' (Martens, 1899) # ''

Biomphalaria temascalensis ''Biomphalaria'' is a genus of air-breathing freshwater snails, Aquatic animal, aquatic pulmonates belonging to the Family (biology), family Planorbidae, the ram's horn snails and their allies. ''Biomphalaria'' is the type genus of the tribe Bi ...

'' (Rangel-Ruiz, 1987) # '' Biomphalaria tenagophila'' (d'Orbigny, 1835)

Old World The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...

(

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

and the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

) species include: Confirmed species using molecular identification methods: # '' Biomphalaria alexandrina'' (Ehrenberg, 1831) # '' Biomphalaria angulosa'' (Mandahl-Barth, 1957) # ''

Biomphalaria camerunensis ''Biomphalaria camerunensis'' is a species of gastropods belonging to the family Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family (biology), family of air-breathing freshwater snails, Aquatic animal, ...

'' (Mandahl-Barth, 1957) # '' Biomphalaria choanomphala'' (E. von Martens, 1879) # '' Biomphalaria pfeifferi'' (Krauss, 1848) # '' Biomphalaria smithi'' (Preston, 1910) - type species # '' Biomphalaria stanleyi'' (Smith, 1888) # '' Biomphalaria sudanica'' (Martens, 1870) There is one known

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

'' Biomphalaria glabrata × Biomphalaria alexandrina'' from Egypt. Suspected species identified using morphological methods: # '' Biomphalaria arabica'' (Melvill & Ponsonby, 1896) # '' Biomphalaria barthi'' (Brown, 1973) # '' Biomphalaria rhodesiensis'' (Mandahl-Barth, 1957) # '' Biomphalaria ruppellii'' (Dunker, 1848) - subspecies: ''B. ruppellii ruppellii''; ''B. ruppellii katangae'' Haas # '' Biomphalaria salinarum'' (Morelet, 1868) # '' Biomphalaria tchadiensis'' (Germain, 1904)

Phylogeny

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

created from mitochondrial and nuclear DNA showing the phylogenic relationships of both New World (16) and Old World (7) species: The topology was consistent with the proposed Neotropical origins of the genus, with the oldest ''Biomphalaria'' fossils being dated from approximately 60 million years ago. However, further analysis of the African ''Biomphalaria'' species found only ''B. camerunensis'' and ''B. pfeifferi'' were the only definitive African species, with the remain species being a part of (or a sister taxa to) the "Nilotic species complex": Biomphalaria Phylogenetic Tree

All of the African ''Biomphalaria'' species have low levels of genetic diversity, which is likely the result of their relatively recent evolutionary history.

Distribution

The origin of the genus ''Biomphalaria'' is American. The ancestor of ''

'' 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

and

, 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 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 US, but they are considered to represent a potentially serious threat as a pest, an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national

quarantine A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...

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 host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

(

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

) for the human parasitic

blood fluke ''Schistosoma'' is a genus of trematodes, commonly known as blood flukes. They are parasitic flatworms responsible for a highly significant group of infections in humans termed ''schistosomiasis'', which is considered by the World Health Organi ...

, ''

Schistosoma mansoni A paired couple of ''Schistosoma mansoni''. ''Schistosoma mansoni'' is a water-borne parasite of humans, and belongs to the group of blood flukes (''Schistosoma''). The adult lives in the blood vessels ( mesenteric veins) near the human inte ...

'', that infects about 83 million people. The human disease

schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever is a neglected tropical helminthiasis, disease caused by parasitism, parasitic Schistosoma, flatworms called schistosomes. It affects both humans and animals. It affects ...

(aka snail fever) caused by all ''

Schistosoma ''Schistosoma'' is a genus of trematodes, commonly known as blood flukes. They are Parasitism, parasitic flatworms responsible for a highly significant group of infections in humans termed ''schistosomiasis'', which is considered by the World H ...

'' species (transmitted also by other snails) infects 200 million people.The Carter Cente
"Schistosomiasis Control Program"
Accessed 20 November 2009. 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.
text
Altogether about 30 species of parasites from Africa and at least 20 species from the

Neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biogeog ...

are known to parasitize ''Biomphalaria''.

References

This article incorporates

public domain The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds ...

text from the Majoros ''et al.'' reference.

External links

{{Authority control Gastropod genera