Sisor is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Sisoridae

Sisoridae

Sisoridae is a family of catfishes . These Asian catfish live in fast-moving waters and often have adaptations that allow them to adhere to objects in their habitat.-Taxonomy:...

. It includes five species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, S. barakensis, S. chennuah, S. rabdophorus, S. rheophilus, and S. torosus.

Taxonomy

Sisor was previously monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

, 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 language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

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

Distribution and habitat

Sisor species are distributed in the Ganges

Ganges River

The Ganges or Ganga, , is a trans-boundary river of India and Bangladesh. The river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India into Bangladesh, where it empties into the Bay of Bengal. By discharge it...

 and Brahmaputra

Brahmaputra River

The Brahmaputra , also called Tsangpo-Brahmaputra, is a trans-boundary river and one of the major rivers of Asia. It is the only Indian river that is attributed the masculine gender and thus referred to as a in Indo-Aryan languages and languages with Indo-Aryan influence...

 drainages in India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. S. barakensis originates from the Barak River

Barak River

The Barak River is one of the major rivers of southern Assam and is a part of the Surma-Meghna River System. It is the biggest and the most important of all the rivers in the Manipur hill territory, from where it originates....

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

Assam

Assam , also, rarely, Assam Valley and formerly the Assam Province , is a northeastern state of India and is one of the most culturally and geographically distinct regions of the country...

 State, India. S. rabdophorus originates from the Ganges drainage, West Bengal

West Bengal

West Bengal is a state in the eastern region of India and is the nation's fourth-most populous. It is also the seventh-most populous sub-national entity in the world, with over 91 million inhabitants. A major agricultural producer, West Bengal is the sixth-largest contributor to India's GDP...

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

Bihar

Bihar is a state in eastern India. It is the 12th largest state in terms of geographical size at and 3rd largest by population. Almost 58% of Biharis are below the age of 25, which is the highest proportion in India....

 and Uttar Pradesh

Uttar Pradesh

Uttar Pradesh abbreviation U.P. , is a state located in the northern part of India. With a population of over 200 million people, it is India's most populous state, as well as the world's most populous sub-national entity...

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

Bihar

Bihar is a state in eastern India. It is the 12th largest state in terms of geographical size at and 3rd largest by population. Almost 58% of Biharis are below the age of 25, which is the highest proportion in India....

 and Delhi

Delhi

Delhi , officially National Capital Territory of Delhi , is the largest metropolis by area and the second-largest by population in India, next to Mumbai. It is the eighth largest metropolis in the world by population with 16,753,265 inhabitants in the Territory at the 2011 Census...

 States, India. The identities of Sisor specimens from the Indus River

Indus River

The Indus River is a major river which flows through Pakistan. It also has courses through China and India.Originating in the Tibetan plateau of western China in the vicinity of Lake Mansarovar in Tibet Autonomous Region, the river runs a course through the Ladakh district of Jammu and Kashmir and...

, Rohini River at Madhopur

Madhopur

-Places:* Madhopur, Rautahat a village in Nepal* Madhopur, Jalandhar a village in India* Madhopur, Punjab...

, and Nepal

Nepal

Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...

 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

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 to the base of the caudal fin and a spine in adipose fin. Also, the uppermost caudal-fin ray is more than half length of body, the branchiostegal
membranes

Ichthyology terms

Ichthyology uses several terms that are unique to the science.Contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z- A :* Abdomen: belly* Abdominal: pertaining to the belly* Actinosts: a series of bones at the base of the pectoral rays....

 are broadly fused to isthmus

Ichthyology terms

Ichthyology uses several terms that are unique to the science.Contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z- A :* Abdomen: belly* Abdominal: pertaining to the belly* Actinosts: a series of bones at the base of the pectoral rays....

, the outer and inner mental barbels

Barbel (anatomy)

A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

 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

Serrated Edge

Serrated Edge is the second album by Tempest. It was their first with a fiddler, and was released in 1992.-Tracks:#Hal-an Tow #Raggle Taggle Gypsy #A Kiss in the Morning Early...

 on the anterior margin of the pectoral spine (also serrated posteriorly), a well-developed maxillary barbel

Barbel (anatomy)

A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

 membrane, and palatal

Palate

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 separate. The palate is divided into two parts, the anterior...

 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 extending beyond the head. The dorsal fin spine is serrate anteriorly and smooth posteriorly.

S. chennua, S. rheophilus, and S. torosus grow to about 9.5–11.6 centimetres (3.7–4.6 in) SL

Fish measurement

Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...

. S. rabdophorus attains a length of about 18.0 cm (7.1 in) SL.