The shark catfishes form 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 ...

Pangasiidae. They are found in fresh and

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

waters across southern

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 ...

, from

Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

. Among the 30-odd members of this family is the plant-eating, endangered Mekong giant catfish ''Pangasianodon gigas'', one of the largest known freshwater fish. Several species are the basis of productive aquaculture industries in Vietnam's

Mekong Delta The Mekong Delta ( or simply ), also known as the Western Region () or South-western region (), is the list of regions of Vietnam, region in southwestern Vietnam where the Mekong, Mekong River River delta, approaches and empties into the sea th ...

Taxonomy and fossil record

Although Pangasiidae forms a

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

group, several studies indicate this group may actually be a subtaxon nested within the family

Schilbeidae Schilbeidae is a family of catfishes native to Africa and Asia. These fish tend to swim in open water. Schilbid catfishes usually have dorsal fins with a short base and a spine, but '' Parailia'' lack a dorsal fin altogether. Most species also p ...

. Thus, Pangasiidae's familial status may not deserve continued recognition. Two

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

pangasiid species are described, '' Cetopangasius chaetobranchus'' from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, and '' Pangasius indicus'', from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. However, the reported age of ''P. indicus'' from the

is debatable, as the Sipang Fauna stratum where it is found has never been officially dated. Therefore, the earliest reliable pangasiid fossil age is of ''C. chaetobranchus'' from the Miocene.

Description

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 ...

is located far forward, close to the head, and is often high and triangular, thus inspiring the common name. The

anal 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 o ...

is somewhat lengthy, with 26–46 rays. Usually, they have two pairs of

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whisker like sensory organ near the mouth (sometimes called whiskers or tendrils). Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the z ...

, maxillary barbels and one pair of chin barbels, though adult Mekong giant catfish have only maxillary barbels. Pangasiids have compressed bodies and single small

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 ...

References

External links

* {{Authority control Fish of South Asia Extant Miocene first appearances Taxa named by Pieter Bleeker