The shark catfishes are a 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...

, the Pangasiidae, 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 found in fresh and brackish waters across southern Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, from Pakistan

Pakistan

Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

 to Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

. Among the 30-odd members of this family is the plant-eating, endangered Mekong giant catfish

Mekong giant catfish

The Mekong giant catfish, Pangasianodon gigas, is a species of catfish in the shark catfish family , native to the Mekong basin in Southeast Asia.-Species characteristics:...

 Pangasianodon gigas, one of the largest known freshwater fishes. Several species have recently become a booming aquaculture success in Vietnam's Mekong Delta.

Taxonomy and fossil record

Although Pangasiidae is known to be a natural group, several studies indicate this group is likely nested within Schilbeidae

Schilbeidae

The schilbid catfishes are a family of catfishes native to Africa and southern Asia. These fish tend to swim in open water....

. Thus, its familial status may not deserve continued recognition.

Two fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 pangasiid species are described, Cetopangasius chaetobranchus

Cetopangasius chaetobranchus

Cetopangasius chaetobranchus is an extinct species of catfish of the family Pangasiidae. This fish was from a Miocene lake fauna from what is now Ban Nong Pia, Phetchabun Province of Thailand....

and Pangasius indicus. However, the reported age of P. indicus from the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 is debatable. Therefore, the earliest reliable pangasiid fossil age is of C. chaetobranchus from the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

.

Description

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...

 is located far forward, close to the head, and is often high and triangular, thus inspiring the common name. The anal fin is somewhat lengthy, with 26–46 rays. There are usually two pairs of 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...

, maxillary barbels and one pair of chin barbels, though in adult Mekong giant catfish there are only maxillary barbels. Pangasiids have a compressed body, and a small adipose fin.