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Concept
Oreochromis
Summary
Oreochromis is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very small ranges; some are seriously threatened, and O. ismailiaensis and O. lidole possibly are extinct. Although Oreochromis primarily are freshwater fish of rivers, lakes and similar habitats, several species can also thrive in brackish waters and some even survive in hypersaline conditions with a salinity that far surpasses that of seawater. In addition to overfishing and habitat loss, some of the more localized species are threatened by the introduction of other, more widespread Oreochromis species into their ranges. This is because they—in addition to competing for the local resources—often are able to hybridize.
Oreochromis are fairly robust fish, and medium–small to very large cichlids that can reach up to in total length depending on the exact species.
Species in this genus, as well as those in several other oreochromine and tilapiine genera, share the common name "tilapia" and historically most were included in the genus Tilapia.
Oreochromis contains more than 30 species, and several undescribed forms exist. Judging from mtDNA sequence analysis, several clades seem to exist. Research is hampered because hybridization runs rampant in these fishes, which confounds mtDNA data (Wami tilapia is an example), and the fast speed of evolution makes choice of appropriate nuclear DNA sequences difficult. A comprehensive genetic study that included almost all the species, as well as the closely related Alcolapia, found that Oreochromis as currently defined is paraphyletic. For example, two Oreochromis species (O. amphimelas and O. esculentus) appear closer to Alcolapia than the remaining Oreochromis, and five other Oreochromis species (O. angolensis, O. lepidurus, O. niloticus, O. schwebischi and O. upembae) appear to be as distant from the "core" Oreochromis as they are from Alcolapia.
Official source
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Ontological neighbourhood
Related concepts (5)
Nile tilapia
The Nile tilapia (Oreochromis niloticus) is a species of tilapia, a cichlid fish native to parts of Africa and the Levant, particularly Israel and Lebanon. Numerous introduced populations exist outside its natural range. It is also commercially known as mango fish (not to be confused with mango tilapia, or Sarotherodon galilaeus), nilotica, or boulti. The Nile tilapia reaches up to in length, and can exceed . As typical of tilapia, males reach a larger size and grow faster than females.
Tilapia
Tilapia (tᵻˈlɑːpiə ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most important species placed in the Coptodonini and Oreochromini. Tilapia are mainly freshwater fish inhabiting shallow streams, ponds, rivers, and lakes, and less commonly found living in brackish water.
Cichlid
Cichlids ˈsɪklᵻdz are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses (Labridae), in the order Perciformes, but molecular studies have contradicted this grouping. On the basis of fossil evidence, it first appeared in Tanzania during the Eocene epoch, about 46–45 million years ago. The closest living relative of cichlids is probably the convict blenny, and both families are classified in the 5th edition of Fishes of the World as the two families in the Cichliformes, part of the subseries Ovalentaria.