Sisor

Taxobox
name = "Sisor"
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Siluriformes
familia = Sisoridae
subfamilia = Sisorinae
genus = "Sisor"
genus_authority = Hamilton, 1822
type_species = "Sisor rabdophorus"
type_species_authority = Hamilton, 1822
subdivision_ranks = Binomial name
subdivision =
"Sisor barakensis"
Vishwanath & Darshan, 2005
"Sisor chennuah"
Ng & Lahkar, 2003
"Sisor rabdophorus"
Hamilton, 1822
"Sisor rheophilus"
Ng, 2003
"Sisor torosus"
Ng, 2003

"Sisor" is a genus of catfishes (order Siluriformes) of the family Sisoridae. It includes five species, "S. barakensis", "S. chennuah", "S. rabdophorus", "S. rheophilus", and "S. torosus".cite journal|url=http://www.mapress.com/zootaxa/2006f/zt01345p096.pdf|title=Genera of the Asian Catfish Families Sisoridae and Erethistidae (Teleostei: Siluriformes)|first=Alfred W.|last=Thomson|coauthors=Page, Lawrence M.|journal=Zootaxa|volume=1345|pages=1–96|year=2006|format=PDF] cite journal|url=http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf|title=Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types|first=Carl J., Jr.|last=Ferraris|journal=Zootaxa|volume=1418|pages=1–628|year=2007|format=PDF]

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

Distribution and habitat

"Sisor" species are distributed in the Ganges and Brahmaputra drainages in India. "S. barakensis" originates from the Barak River of the Brahmaputra drainage in India. "S. chennuah" inhabits the Brahmaputra drainage in Assam State, India. "S. rabdophorus" originates from the Ganges drainage, West Bengal States, India. "S. rheophilus" originates from the Ganges drainage, Bihar and Uttar Pradesh States, India. "S. torosus" lives in the Ganges drainage, Bihar and Delhi States, India.cite journal|title=A revision of the south Asian sisorid catfish genus "Sisor" (Teleostei: Siluriformes)|first=Heok Hee|last=Ng|journal=Journal of Natural History|date=10 December 2003|volume=37|pages=2871–2883|doi=10.1080/00222930210158780] The identities of "Sisor" specimens from the Indus River, Rohini River at Madhopur, and Nepal 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 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 branchiostegalmembranes are broadly fused to isthmus, 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 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.FishBase species|genus=Sisor|species=chennua|year=2007|month=July] FishBase species|genus=Sisor|species=rheophilus|year=2007|month=July] FishBase species|genus=Sisor|species=torosus|year=2007|month=July] "S. rabdophorus" attains a length of about 18.0 cm (7.1 in) SL.FishBase species|genus=Sisor|species=rabdophorus|year=2007|month=July]

References