Exostoma
Encyclopedia
Exostoma is a genus
of catfish
es (order
Siluriformes) of the family
Sisoridae
. It includes four species
that E. berdmorei, E. labiatum, E. stuarti, and E. vinciguerrae.
s of E. labiatum.
drainage of northeast India
, and east and south to the Salween
drainages in Burma. E. berdmorei is found in the Sittang
and Salween drainages in Burma. E. labiatum is known from the Brahmaputra drainage in northeast India, but has also been recorded in the Salween drainage in Burma, the Ayeyarwady
drainage in China
, and the Brahmaputra drainage in Tibet
and Burma. E. stuarti is from the Ayeyarwady River of Burma and India; however, it has not been collected since its original discovery.
E. labiatum is found in mountain rapids.
openings not extending onto the underside (venter), homodont dentition of oar-shaped, distally flattened teeth in both jaws, the tooth patches separated in upper jaw, and 10–11 branched pectoral rays. The head is depressed with a broadly rounded snout. The body is elongate and flattened ventrally to the pelvic fins. The eyes are minute, dorsally located, and under the skin (subcutaenous). The lips are thick, fleshy, and papilla
ted. The teeth are small to large, moveable, oar-shaped, flattened distally and directed posteriorly in distinct patches.
E. stuarti is recorded to grow to 5.6 centimetres (2.2 in) SL
. E. berdmorei and E. labiatum grow to about 10–11 cm (3.94–4.33 in) TL
.
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 four 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...
that E. berdmorei, E. labiatum, E. stuarti, and E. vinciguerrae.
Taxonomy
In a 2007 checklist of sisorid and erethistid catfishes, Thomson lists E. stuarti and E. vinciguerrae as valid species. In a 2007 checklist of catfishes, Ferraris lists these two species as species inquerendae, noting that these species are either treated as valid or as synonymSynonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
s of E. labiatum.
Distribution and habitat
Exostoma species are distributed in the BrahmaputraBrahmaputra 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...
drainage of northeast 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...
, and east and south to the Salween
Salween River
The Salween is a river, about long, that flows from the Tibetan Plateau into the Andaman Sea in Southeast Asia. It drains a narrow and mountainous watershed of that extends into the countries China, Burma and Thailand. Steep canyon walls line the swift, powerful and undammed Salween, one of the...
drainages in Burma. E. berdmorei is found in the Sittang
Sittang River
The Sittaung is a river in south central Myanmar in Bago Division. The Pegu Range separates its basin from that of the Irrawaddy. The river originates at the edge of the Shan Plateau southeast of Mandalay, and flows southward to the Gulf of Martaban...
and Salween drainages in Burma. E. labiatum is known from the Brahmaputra drainage in northeast India, but has also been recorded in the Salween drainage in Burma, the Ayeyarwady
Ayeyarwady River
The Irrawaddy River or Ayeyarwady River is a river that flows from north to south through Burma . It is the country's largest river and most important commercial waterway. Originating from the confluence of the N'mai and Mali rivers, it flows relatively straight North-South before emptying through...
drainage in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and the Brahmaputra drainage in Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...
and Burma. E. stuarti is from the Ayeyarwady River of Burma and India; however, it has not been collected since its original discovery.
E. labiatum is found in mountain rapids.
Description
Exostoma is distinguished by having a continuous groove behind the lips (post-labial groove), the gillGill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
openings not extending onto the underside (venter), homodont dentition of oar-shaped, distally flattened teeth in both jaws, the tooth patches separated in upper jaw, and 10–11 branched pectoral rays. The head is depressed with a broadly rounded snout. The body is elongate and flattened ventrally to the pelvic fins. The eyes are minute, dorsally located, and under the skin (subcutaenous). The lips are thick, fleshy, and papilla
Papilla (fish mouth structure)
The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...
ted. The teeth are small to large, moveable, oar-shaped, flattened distally and directed posteriorly in distinct patches.
E. stuarti is recorded to grow to 5.6 centimetres (2.2 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:...
. E. berdmorei and E. labiatum grow to about 10–11 cm (3.94–4.33 in) TL
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:...
.