''Sisor'' 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 ...

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

es native to

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Taxonomy

''Sisor'' was previously

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, containing only ''S. rabdophorus'', prior to a review of the genus in 2003 in which the three species ''S. chennuah'', ''S. rheophilus'', and ''S. torosus'' were described. ''S. barakensis'' was described in 2005. ''S. rabdophorus'' is sometimes spelled ''S. rhabdophorus''; this is meant to correct the misspelling of the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

word ''rhabdos'' meaning ''rod''. However, this is not a valid emendation.

Species

There are currently six recognized species in this genus: * '' Sisor barakensis'' Vishwanath & Darshan, 2005 * '' Sisor chennuah'' Ng & Lahkar, 2003 * '' Sisor pakistanicus'' Javed & Mirza, 2011Javed, M.N. & Mirza, M.R. (2011): Sisor pakistanicus (Teleostei, Sisoridae), a new catfish from the river Chenab, Pakistan.
Biologia (Pakistan), 57 (1&2)
15-21.'' * ''

Sisor rabdophorus ''Sisor'' is a genus of catfishes native to Asia. Taxonomy ''Sisor'' was previously monotypic, containing only ''S. rabdophorus'', prior to a review of the genus in 2003 in which the three species ''S. chennuah'', ''S. rheophilus'', and ''S. tor ...

Hamilton Hamilton may refer to: * Alexander Hamilton (1755/1757–1804), first U.S. Secretary of the Treasury and one of the Founding Fathers of the United States * ''Hamilton'' (musical), a 2015 Broadway musical by Lin-Manuel Miranda ** ''Hamilton'' (al ...

, 1822 * ''

Sisor rheophilus ''Sisor'' is a genus of catfishes native to Asia. Taxonomy ''Sisor'' was previously monotypic, containing only ''S. rabdophorus'', prior to a review of the genus in 2003 in which the three species ''S. chennuah'', ''S. rheophilus'', and ''S. tor ...

'' Ng, 2003 * ''

Sisor torosus ''Sisor'' is a genus of catfishes native to Asia. Taxonomy ''Sisor'' was previously monotypic, containing only ''S. rabdophorus'', prior to a review of the genus in 2003 in which the three species ''S. chennuah'', ''S. rheophilus'', and ''S. tor ...

'' Ng, 2003

Distribution and habitat

''Sisor'' species are distributed in the

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 ...

and

Brahmaputra The Brahmaputra is a trans-boundary river which flows through Southwestern China, Northeastern India, and Bangladesh. It is known as Brahmaputra or Luit in Assamese, Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, and ...

drainages in

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 ...

. ''S. barakensis'' originates from the

Barak River The Barak River or Barbakro or Agu flows through the states of Manipur, Mizoram and Assam in India. It flows into Bangladesh where it bifurcates into the Surma river and the Kushiyara river which converge again to become the Meghna river before ...

of the Brahmaputra drainage in India. ''S. chennuah'' inhabits the Brahmaputra drainage in

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 ...

State, India. ''S. rabdophorus'' originates from the Ganges drainage,

West Bengal West Bengal (; Bengali language, Bengali: , , abbr. WB) is a States and union territories of India, state in the East India, eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabi ...

States, India. ''S. rheophilus'' originates from the Ganges drainage,

Bihar Bihar ( ) is a states and union territories of India, state in Eastern India. It is the list of states and union territories of India by population, second largest state by population, the List of states and union territories of India by are ...

and

Uttar Pradesh Uttar Pradesh ( ; UP) is a States and union territories of India, state in North India, northern India. With over 241 million inhabitants, it is the List of states and union territories of India by population, most populated state in In ...

States, India. ''S. torosus'' lives in the Ganges drainage,

and

Delhi Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, but spread chiefly to the west, or beyond its Bank (geography ...

States, India. The identities of ''Sisor'' specimens from the

Indus River The Indus ( ) is a transboundary river of Asia and a trans-Himalayas, Himalayan river of South Asia, South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in the Western Tibet region of China, flows northw ...

Rohini River The Rohni (also known as Rohini or Rohin) is a river rise in the Chure or Sivalik Hills in Kapilvastu and Rupandehi Districts of Nepal's Lumbini Zone and flows south into Uttar Pradesh state, India. At Gorakhpur it becomes a left bank tributar ...

at Madhopur, and

Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...

have not yet been confirmed. ''S. rheophilus'' has been found in fast-moving rivers with sandy bottoms. ''S. rabdophorus'' also inhabits streams with sandy bottoms and strong currents.

Description

''Sisor'' is distinguished from all other erethistids and sisorids by the presence of a series of bony plates extending from the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

to the base of the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

and a spine in

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

. Also, the uppermost caudal-fin ray is more than half length of body, the branchiostegal membranes are broadly fused to

isthmus An isthmus (; : isthmuses or isthmi) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea count ...

, the outer and inner mental barbels are widely separated with the origin of outer barbels anterior to origin of inner barbels, the lower jaw teeth are minute, dentition essentially consisting of roughened plate, large serrations on the anterior margin of the pectoral spine (also serrated posteriorly), a well-developed maxillary barbel membrane, and

palatal The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sepa ...

teeth absent. The head is moderately narrow and strongly depressed. The body is extremely narrow and strongly depressed. The eyes are small, dorsolaterally located, and under the skin (subcutaneous). The maxillary barbels do not extend beyond the head. The dorsal fin spine is serrate anteriorly and smooth posteriorly. ''S. chennua'', ''S. rheophilus'', and ''S. torosus'' grow to about SL. ''S. rabdophorus'' attains a length of about SL.

References

{{Taxonbar, from=Q5023933 Sisoridae Fish of South Asia Fish of India Fauna of Pakistan Freshwater fish genera Catfish genera Taxa named by Francis Buchanan-Hamilton