''Glyphis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

in the

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

Carcharhinidae, commonly known as the river sharks. They live in rivers or coastal regions in and around south-east Asia and parts of Australia.

Taxonomy

This genus contains only three extant species. Further species could easily remain undiscovered, due to their secretive habits. This genus was thought to contain five different

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 appropriat ...

, but recent studies on molecular data revealed that the species ''

Glyphis gangeticus The Ganges shark (''Glyphis gangeticus'') is a critically endangered species of requiem shark found in the Ganges River (Padma River) and the Brahmaputra River of Bangladesh and India. It is often confused with the more common bull shark (''Car ...

'' has an irregular distribution in the Indo-West Pacific region.

Species

The recognized species in this genus are: * ''

'' ( J. P. Müller &

Henle Henle can refer to: *Friedrich Gustav Jakob Henle, a German physician, pathologist and anatomist (1809–1885) ** Loop of Henle In the kidney, the loop of Henle () (or Henle's loop, Henle loop, nephron loop or its Latin counterpart ''ansa nephroni ...

, 1839) (

Ganges The Ganges ( ) (in India: Ganga ( ); in Bangladesh: Padma ( )). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international river to which India, Bangladesh, Nepal and China are the riparian states." is ...

shark) * '' Glyphis garricki'' L. J. V. Compagno, W. T. White &

Last A last is a mechanical form shaped like a human foot. It is used by shoemakers and cordwainers in the manufacture and repair of shoes. Lasts typically come in pairs and have been made from various materials, including hardwoods, cast iron ...

, 2008 (northern river shark) * ''

Glyphis glyphis The speartooth shark (''Glyphis glyphis'') is a rare species of river shark, belonging to the family Carcharhinidae. It inhabits coastal marine waters and tidal reaches of large tropical rivers in northern Australia and New Guinea. Despite ...

'' ( J. P. Müller &

, 1839) (speartooth shark) * †''

Glyphis hastalis ''Glyphis hastalis'' is a species of extinct river shark from Great Britain. Modern relatives include the Ganges shark and speartooth shark The speartooth shark (''Glyphis glyphis'') is a rare species of river shark, belonging to the family ...

'' Agassiz, 1843 * †''

Glyphis pagoda ''Glyphis pagoda'' is an extinct river shark from the Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the ...

'' (Noetling, 1901)

Distribution and habitat

Their precise geographic range is uncertain, but the known species are documented in parts of

South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;; ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torres ...

, and

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

. Of the three currently described species, the Ganges shark is restricted to freshwater, while the

northern river shark The northern river shark or New Guinea river shark (''Glyphis garricki'') is a species of requiem shark, in the family Carcharhinidae, found in scattered tidal rivers and associated coastal waters in northern Australia and in Papua New Guinea ...

and the

speartooth shark The speartooth shark (''Glyphis glyphis'') is a rare species of river shark, belonging to the family Carcharhinidae. It inhabits coastal marine waters and tidal reaches of large tropical rivers in northern Australia and New Guinea. Despite be ...

are found in coastal marine waters, as well. While the

bull shark The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in ri ...

(''Carcharhinus leucas'') is sometimes called both the river shark and the Ganges shark, it should not be confused with the river sharks of the genus ''Glyphis''. Bull sharks evolved to have their offspring in freshwater, therefore, making them safe to roam in the water while other sharks are able to survive in saltwater.

Conservation

River sharks remain very poorly known to science. They are facing a critically endangered status since they are so poorly studied, and people know very little about their population and life history. One of the primary threats to river sharks is habitat degradation, which includes human development, pollution, and fishing. The river shark is known to be one of the rarest sharks in the world. They have been found in nine different tidal areas, which consist of muddy waters with a low salinity. Their placement in connection to coastal marine waters indicates that they are usually born around October.

Images

File:Glyphis gangeticus.jpg, Ganges shark (''G. gangeticus'') File:Glyphis garricki csiro-nfc.jpg, Northern river shark (''G. garricki'') File:Glyphis glyphis csiro-nfc.jpg, Speartooth shark (''G. glyphis'')

References

Jabado, R. W., et al. “A Rare Contemporary Record of the Critically Endangered Ganges Shark Glyphis Gangeticus.” Journal of Fish Biology, vol. 92, no. 5, Mar. 2018, pp. 1663–1669., doi:10.1111/jfb.13619. White WT, Appleyard SA, Sabub B, Kyne PM, Harris M, Lis R, et al. (2015) Rediscovery of the Threatened River Sharks, Glyphis garricki and G. glyphis, in Papua New Guinea. PLoS ONE 10(10): e0140075. https://doi.org/10.1371/journal.pone.0140075 Taxa named by Louis Agassiz {{Shark-stub