''Glyphis'' 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 ...

in 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 ...

Carcharhinidae, commonly known as the river sharks. They live in rivers or coastal regions in and around south-east Asia, Africa 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 A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, but recent studies on molecular data revealed that the species '' Glyphis gangeticus'' has an irregular distribution in the Indo-West Pacific region. The genus Glyphis is closest to the genus Lamiopsis.

Species

The recognized species in this genus are: * ''Glyphis fowlerae'' Compagno, White & Cavanagh, 2010 (Borneo river shark) synonym of ''G. gangeticus'' * '' Glyphis gangeticus'' ( J. P. Müller & Henle, 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 which goes through India, Bangladesh, Nepal and China." is a trans-boundary rive ...

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 come in many styles and sizes, depending on the exact job they are designed for. Common variations ...

, 2008 (northern river shark) * '' Glyphis glyphis'' ( J. P. Müller & Henle, 1839) (speartooth shark) * '' Glyphis hastalis'' Agassiz, 1843 * '' Glyphis pagoda'' (Noetling, 1901) * ''Glyphis siamensis'' (Steindachner, 1896) (

Irrawaddy river The Irrawaddy River (, , Ayeyarwady) is the principal river of Myanmar, running through the centre of the country. Myanmar’s most important commercial waterway, it is about 1,350 miles (2,170 km) long. Originating from the confluence of the ...

shark) synonym of ''G. gangeticus''

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#Asia, subregion of Asia that is defined in both geographical and Ethnicity, ethnic-Culture, cultural terms. South Asia, with a population of 2.04 billion, contains a quarter (25%) of the world's populatio ...

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. Of the three currently described species, the

Ganges shark 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 India and Bangladesh. It is often confused with the more common bull shark (''Car ...

is restricted to freshwater, while the northern river shark and the speartooth shark 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 riv ...

(''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''. River 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 researchers. River sharks were thought to be extinct until the end of the 20th century, when small populations were discovered in Borneo and Northern Australia. Now, they face a critically endangered status as they are so poorly studied, and people know very little about their population and life history. ''Glyphis gangeticus'' uses the Ganges River as nursery grounds and the birthplace of many Ganges shark offspring, however the population has been severely diminished owing to a long history of fishing and other pollution-related issues in the Northern

Arabian Sea The Arabian Sea () is a region of sea in the northern Indian Ocean, bounded on the west by the Arabian Peninsula, Gulf of Aden and Guardafui Channel, on the northwest by Gulf of Oman and Iran, on the north by Pakistan, on the east by India, and ...

. Additionally, India, where the Ganges river flows, is reported to be one of the top three greatest shark and ray capturers in the world, accounting for up to nine percent of reported global landings (Jabado et al., 2018). They are reported from the Zambezi river in Africa. 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

Taxa named by Louis Agassiz {{More categories, date=September 2024