''Biomphalaria sudanica'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of air-breathing

freshwater snail Freshwater snails are gastropod mollusks which 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 ...

, an 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 includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Planorbidae, the

ram Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * Ra ...

's horn snails. ''Biomphalaria sudanica'' has a discoidal, brown shell with an approximate shell diameter of 9–11 mm. ''Biomphalaria sudanica'' is a medically important pest, due to it being 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 a ...

of the intravascular trematode genus, ''

Schistosoma ''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 Organ ...

''.

Distribution

This is an African ''Biomphalaria'' species, and occurs mainly in East Africa: * The River Nile, Shambat,

Sudan Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...

. * Lake Albert,

Uganda }), is a landlocked country in East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territor ...

. (Lake Albert is between

and

Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

) *

Lake Kyoga Lake Kyoga (literally 'the place of bathing' in Runyoro language) is a large shallow lake in Uganda, about in area and at an elevation of 1,033 metres. The Victoria Nile flows through the lake on its way from Lake Victoria to Lake Albert. The mai ...

. *

Lake Ziway Hora-Dambal also known as Lake Zway or Dambal ( Oromo: ''Hora Dambal'', Amharic: ዟይ ሐይቅ) is one of the freshwater Rift Valley lakes of Ethiopia. It is located about 100 miles south of Addis Ababa, on the border between the Oromia and S ...

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...

Phylogeny

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

showing the phylogenic relations of species in the genus ''Biomphalaria'':

Ecology

''Biomphalaria sudanica'' is found in shallow water near the shoreline in Lake Albert. Despite being a pulmonate, ''Biomphalaria sudanica'' is well adapted to use the oxygen from water (but not as well as ''

Planorbis ''Planorbis'' is a genus of air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails, or planorbids. All species in this genus have sinistral or left-coiling shells.Bouchet, P.; Rosen ...

''). This ability is useful for living in swamp habitats. The

population density Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopul ...

of ''Biomphalaria sudanica'' varies during the year. The highest population density of ''Biomphalaria sudanica'' is in

from June to August, at the end of

rainy season The rainy season is the time of year when most of a region's average annual rainfall occurs. Rainy Season may also refer to: * ''Rainy Season'' (short story), a 1989 short horror story by Stephen King * "Rainy Season", a 2018 song by Monni * ''T ...

. The higher densities of ''Biomphalaria sudanica'' occur in habitats with the Common Water Hyacinth ''

Eichhornia crassipes ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive species, invasive outside its native range ...

'' in

Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...

.]. It was experimentally detected under laboratory conditions that gastropod shell, shells of ''Biomphalaria sudanica'' are bigger in waters with higher concentration of

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

than in waters with low calcium.

Parasites

''Biomphalaria sudanica'' is an

for ''

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 ...

'' and for ''

Schistosoma rodhaini ''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 Organ ...

''. Infestation with schistosomes in the Lake Victoria basin is about 1%, but can be up to 50% in the case of ''Schistosoma mansoni'' and up to 6% in ''Schistosoma rodhaini'' in some localities.

Distribution

Phylogeny

Ecology

Parasites

References

Further reading