''Indoplanorbis'' 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 snails 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 ...

. They are

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

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 ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the

ram Ram, ram, or RAM most commonly refers to: * A male sheep * Random-access memory, computer memory * Ram Trucks, US, since 2009 ** List of vehicles named Dodge Ram, trucks and vans ** Ram Pickup, produced by Ram Trucks Ram, ram, or RAM may also ref ...

's horn snails

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 ...

Bulinidae. The only extant species is widely distributed across the tropics and serves as an important

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 ...

for several

trematode Trematoda is a Class (biology), class of flatworms known as trematodes, and commonly as flukes. They are obligate parasite, obligate Endoparasites, internal parasites with a complex biological life cycle, life cycle requiring at least two Host ( ...

parasites. The invasive nature and ecological tolerance of ''Indoplanorbis exustus'' add to its importance in veterinary and medical science.

Taxonomy

The genus ''Indoplanorbis'' has one extant and one extinct fossil species. It has a long history and wide geographical range, and is thought to have still additional species.

Phylogeographic Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of ge ...

research revealed the phylogenetic depth of divergences between the Indian clades and Southeast Asian clades, and together with habitat and parasitological differences suggests that ''Indoplanorbis'' may comprise more than one extant species. The most phylogenetically related genus to ''Indoplanorbis'' is genus ''

Bulinus ''Bulinus'' is a genus of small tropical freshwater snails, aquatic gastropod mollusks in the family Bulinidae, the ramshorn snails and their allies.MolluscaBase eds. (2020). MolluscaBase. Bulinus O. F. Müller, 1781. Accessed through: World R ...

''.

Biogeography

Meier-Brook (1984) adopted an African (

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

n) origin for ''Indoplanorbis'' with rafting to Asia since the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

on the northward migrating

Indian craton The geology of India is diverse. Different regions of the Indian subcontinent contain rocks belonging to different geologic periods, dating as far back as the Eoarchean Era. Some of the rocks are very deformed and altered. Other deposi ...

; this author also considered a Europe to Southwest Asia tract or an Africa to South India dispersal. Morgan et al. (2002) attributed the occurrence of ''Indoplanorbis'' in India to colonization (from Africa) via the Middle East land connection. Clearly the two different dispersal mechanisms imply very different chronologies; the Gondwanan vicariance hypothesis implies that proto-''Indoplanorbis'' has been present in India since the late Eocene (35 Ma; India: Asia collision), whereas dispersal via the Sinai-Levant suggests a Plio-

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

arrival. The results by Liu et al. (2010) indicated a radiation beginning in the late Miocene with a divergence of an ancestral bulinine lineage into

Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...

and peninsular India clades. A Southeast Asian clade diverged from the peninsular India clade late-Pliocene; this clade then radiated at a much more rapid pace to colonize all of the sampled range of ''Indoplanorbis'' in the mid-Pleistocene. Indoplanorbis exustus map

Distribution

The present range is across

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

, Nepal,

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

, Southeast Asia (for example

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

), central Asia (

Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central Asia and South Asia. It is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran borde ...

), Arabia and Africa. The genus is also found in the Middle East (

Oman Oman, officially the Sultanate of Oman, is a country located on the southeastern coast of the Arabian Peninsula in West Asia and the Middle East. It shares land borders with Saudi Arabia, the United Arab Emirates, and Yemen. Oman’s coastline ...

and

Socotra Socotra, locally known as Saqatri, is a Yemeni island in the Indian Ocean. Situated between the Guardafui Channel and the Arabian Sea, it lies near major shipping routes. Socotra is the largest of the six islands in the Socotra archipelago as ...

) and

Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, ...

and the Ivory Coast; this is attributed to recent introductions by human activities.Brown D. S. (1994). ''Freshwater snails of Africa and their medical importance''. London: Taylor & Francis. 20
208
. In contrast to Asia, the well documented appearance of the snail in Africa (e.g., Nigeria
abstract
and Ivory Coast) and more recently (2002) in the Lesser Antilles, is almost certainly the result of introductions through human activities over the last 50–100 years.

References

This article incorporates CC-BY-2.0 text from the reference..

External links

* Baker F. C. (1945). ''The molluscan family Planorbidae''. The University of Illinois Press, Urbana
196
201. * Raut S. K. (1986). "Disease transmitting snails. II. Population studies of ''Indoplanorbis exustus'' Deshayes." First year PRS Thesis in Science, University of Calcutta. * * . * {{Taxonbar, from1=Q18585564, from2=Q3791090 Monotypic gastropod genera Bulinidae