Ompok 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...

 Siluridae.

They are sometimes called "butter catfishes", but this can also refer to the Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

n genus Schilbe

Schilbe

Schilbe is a catfish genus in the family Schilbeidae. Some are colloquially called "butter catfishes", though this may also refer to the Asian genus Ompok of the family Siluridae.It includes the following species:...

of the family Schilbeidae

Schilbeidae

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

.

Taxonomy

The genus is recognized to be paraphyletic

Paraphyly

A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...

. The species of Ompok have been grouped into species groups, such as the Ompok bimaculatus group (ie. O. bimaculatus, O. malabaricus, O. miostomus), the O. eugeneiatus group (ie. O. eugeneiatus, O. pinnatus), the O. hypophthalmus group (ie. O. hypopthalmus, O. rhabdinurus, O. urbaini), and the O. leiacanthus group (O. fumidus, O. jaynei, O. leiacanthus). On the other hand, the monophyly

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 of these species groups is not strong enough to reassign species to other genera.

The O. eugeneiatus group is likely to be more closely related to Kryptopterus

Kryptopterus

Kryptopterus is a genus of catfishes belonging to the family Siluridae. They are found in freshwater throughout Southeast Asia. The scientific name comes from Ancient Greek kryptós + ptéryx...

than the other Ompok species. According to the recent catfish checklist, O. eugeneiatus has been reclassified into Kryptopterus, however O. pinnatus has not.

Species listed in Ferraris, 2007 and a more recently described species are below:

• Ompok bimaculatus (Bloch
  Marcus Elieser Bloch
  Marcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
  
  , 1794)
• Ompok binotatus Ng, 2002
• Ompok borneensis (Steindachner
  Franz Steindachner
  Franz Steindachner was an Austrian zoologist.- Work and career :Being interested in natural history, Steindachner took up the study of fossil fishes on the recommendation of his friend Eduard Suess...
  
  , 1901)
• Ompok fumidus Tan & Ng, 1996
• Ompok hypophthalmus (Bleeker, 1846)
• Ompok jaynei Fowler, 1905
• Ompok leiacanthus (Bleeker, 1853)
• Ompok malabaricus (Valenciennes
  Achille Valenciennes
  Achille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
  
  , 1840)
• Ompok miostomus Vaillant
  Léon Vaillant
  Léon Louis Vaillant was a French zoologist. He is most famous for his work in the areas of herpetology, malacology, and ichthyology...
  
  , 1902
• Ompok pabda (Hamilton, 1822)
• Ompok pabo (Hamilton, 1822)
• Ompok pinnatus Ng, 2003
• Ompok platyrhynchus Ng & Tan, 2004
• Ompok pluriradiatus Ng, 2002
• Ompok rhadinurus Ng, 2003
• Ompok sindensis (Day
  Francis Day
  Francis Day CIE was Inspector-General of Fisheries in India and Burma and an ichthyologist.He was born on 2 March 1829 Maresfield, Sussex, UK third son of William and Ann Day. He became the medical officer in the Madras Presidency, East India Company services in 1852.Francis Day was created a...
  
  , 1877)
• Ompok supernus Ng, 2008
• Ompok urbaini (Fang & Chaux, 1949)
• Ompok weberi (Hardenberg, 1936)

Distribution and habitat

Ompok species are usually found in lakes and large rivers throughout South

South Asia

South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...

 and Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

.