Haplochromis
Encyclopedia
Haplochromis is a ray-finned fish genus
in the family
Cichlidae. It has been used as the default "wastebin taxon
" for Pseudocrenilabrinae
cichlids of the East African Rift
, and as such became the "largest" fish
"genus". Many of these cichlids are popular aquarium
fishes; like similar Haplochromini they are known as "haplos", "happies" or "haps" among aquarium enthusiasts.
The genus was established by F.M. Hilgendorf
in 1888. It was originally conceived as a subgenus
of A.C.L.G. Günther
's "Chromis", at that time an even larger "wastebin genus" for Pseudocrenilabrinae
cichlids. The type species
of Hilgendorf was H. obliquidens
. "Chromis" of Günther turned out to be a junior homonym of G. Cuvier
's ocean
fish genus Chromis
, established in 1814 already, and was abolished. As the years went by, other genera of (mostly) Haplochromini were lumped with and split again
from Haplochromis, and the final delimitation of the clade
around H. obliquidens is not yet done.
(Lates niloticus) to Lake Victoria
after 1954 severely upset the lake's ecosystem
. By the late 1970s, the perch's population
was approaching carrying capacity
, and the smaller cichlids were fair game for the huge carnivorous Lates, The Nile Tilapia (Oreochromis niloticus), an adaptable generalist
, was also introduced and competed with the often specialized endemic cichlids of the lake for food and other resources. When the Nile Perch stocks finally declined again in the late 1980s, an estimated 200 Haplochromini species
(mostly Haplochromis) had become extinct – many of these had only been scientifically described a few years before their demise, and additional ones were only known or suspected to exist, but never properly studied or described.
While the stocks of those species that survived are in many cases recovering, the lake ecosystem has changed irrevocably. It is being observed that the entire trophic web has been upset. But still, evolution
runs its course: those Lake Victoria Haplochromis that still exist are in many cases adapting
to new food sources, and in time speciation
is likely to set in and produce a new adaptive radiation
of these fishes. Until then, however, the ecological balance of the lake is still on the brink, and many of the cichlids that survived the peak population of Lates are still Critically Endangered
and close to extinction.
of the tribe
Haplochromini. Most of the tribe's members were at one time or another included in the present genus, but in many cases this was only temporary. Around the year 1900 as well 100 years later, there was a trend to split
up the genus; especially in the mid-20th century on the other hand, most authors lumped any and all Haplochromini that were not conspicuously distinct in the type genus.
While a number of African Rift Valley ciclids are certainly very close relatives of H. obliquidens
, the type species
of the present genus, it is not very clear where to draw the boundary of Haplochromis with regard to its relatives. Still, several genera are nowadays recognized as distinct by many authors and scientific databases such as FishBase
(see below); in particular the Haplochromini from Lake Tanganyika
and Lake Malawi
are usually removed form Haplochromis. The genus delimitation in the entire tribe remains badly resolved however, and further changes in taxonomy
are likely in the future. In particular between Haplochromis, Astatotilapia
and Thoracochromis
, species have been moved to and fro over the years. The habit of Pseudocrenilabrinae
to hybridize is hampering molecular phylogenetic studies based on mtDNA alone, while trophic morphs of a single species
may appear to be distinct "species" if they are not phylogenetically studied. Several proposed genera are again included in Haplochromis at present, but it cannot be ruled out that some of these will eventually be recognized as valid again.
places about 220 species
in Haplochromis. In addition, there are distinct several populations known which probably represent additional species (see below). The species list here follows FishBase, except for recognizing Pundamilia
as distinct:
fish trade. A number of them is likely to represent undescribed distinct species
; others might just be subspecies
or color morphs. Whether they all belong in Haplochromis is, of course, doubtful. Some of these populations are:
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Among other genera
of Haplochromini that were formerly included here, many are small or monotypic
. The distinctness of these is highly doubtful, as they may just be distinct lineages of Haplochromis or other haplochromines. That nonwithstanding, Haplochromini genera to which some former "Haplochromis" have been removed are in particular:
Some other Pseudocrenilabrinae
were also – mainly by early authors – included in Haplochromis, even though they are not members of its tribe
. These are:
confusion affecting Haplochromis and its allies, it is hardly surprising that the genus has a large number of junior synonyms. Most referred to small or monotypic genera that were once considered distinct, but are nowadays included in Haplochromis again, if only to wait for a major review of their status. Synonyms are:
and sometimes other genera listed above are also synonymized.
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...
in 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...
Cichlidae. It has been used as the default "wastebin taxon
Wastebin taxon
Wastebasket taxon is a term used in some taxonomic circles to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by their lack of one or more distinct character states or by their not belonging to one or more other taxa...
" for Pseudocrenilabrinae
Pseudocrenilabrinae
The Pseudocrenilabrinae is a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. Previous authors recognized additional African...
cichlids of the East African Rift
East African Rift
The East African Rift is an active continental rift zone in eastern Africa that appears to be a developing divergent tectonic plate boundary. It is part of the larger Great Rift Valley. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates...
, and as such became the "largest" fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
"genus". Many of these cichlids are popular aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fishes; like similar Haplochromini they are known as "haplos", "happies" or "haps" among aquarium enthusiasts.
The genus was established by F.M. Hilgendorf
Franz Martin Hilgendorf
Franz Martin Hilgendorf was a German zoologist and paleontologist. Hilgendorf's research on fossil snails from the Steinheim crater in the early 1860s became a palaeontological evidence for the theory of evolution published by Charles Darwin in 1859.-Life and work:Franz Hilgendorf was born...
in 1888. It was originally conceived as a subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
of A.C.L.G. Günther
Albert C. L. G. Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther , was a German-born British zoologist, ichthyologist, and herpetologist....
's "Chromis", at that time an even larger "wastebin genus" for Pseudocrenilabrinae
Pseudocrenilabrinae
The Pseudocrenilabrinae is a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. Previous authors recognized additional African...
cichlids. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Hilgendorf was H. obliquidens
Haplochromis obliquidens
Haplochromis obliquidens is a species of fish in the Cichlidae family. This is the type species of Haplochromis.It is found in Kenya, Tanzania, and Uganda. Its natural habitat is freshwater lakes. It is not considered a threatened species by the IUCN, but its numbers have declined in recent decade,...
. "Chromis" of Günther turned out to be a junior homonym of G. Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
's ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
fish genus Chromis
Chromis
Chromis is a genus of fish in the family Pomacentridae. While the term Damselfish describes a group of marine fish larger than just one genus, most damselfish are in the genus Chromis...
, established in 1814 already, and was abolished. As the years went by, other genera of (mostly) Haplochromini were lumped with and split again
Lumpers and splitters
Lumping and splitting refers to a well-known problem in any discipline which has to place individual examples into rigorously defined categories. The lumper/splitter problem occurs when there is the need to create classifications and assign examples to them, for example schools of literature,...
from Haplochromis, and the final delimitation of the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
around H. obliquidens is not yet done.
Extinction crisis in Lake Victoria
The introduction of Nile PerchNile perch
The Nile perch is a species of freshwaterfish in family Latidae of order Perciformes. It is widespread throughout muchof the Afrotropic ecozone, being native to the Congo, Nile, Senegal, Niger, and Lake Chad, Volta, Lake Turkana and other river basins. It also occurs in the brackish waters of...
(Lates niloticus) to Lake Victoria
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
after 1954 severely upset the lake's ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. By the late 1970s, the perch's population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
was approaching carrying capacity
Carrying capacity
The carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment...
, and the smaller cichlids were fair game for the huge carnivorous Lates, The Nile Tilapia (Oreochromis niloticus), an adaptable generalist
Generalist
Generalist may refer to:* a person with a wide array of knowledge, the opposite of which is a specialist.* a physician who is focused on primary care and is not a specialist in a certain medical field...
, was also introduced and competed with the often specialized endemic cichlids of the lake for food and other resources. When the Nile Perch stocks finally declined again in the late 1980s, an estimated 200 Haplochromini 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...
(mostly Haplochromis) had become extinct – many of these had only been scientifically described a few years before their demise, and additional ones were only known or suspected to exist, but never properly studied or described.
While the stocks of those species that survived are in many cases recovering, the lake ecosystem has changed irrevocably. It is being observed that the entire trophic web has been upset. But still, evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
runs its course: those Lake Victoria Haplochromis that still exist are in many cases adapting
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
to new food sources, and in time speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
is likely to set in and produce a new adaptive radiation
Adaptive radiation
In evolutionary biology, adaptive radiation is the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different...
of these fishes. Until then, however, the ecological balance of the lake is still on the brink, and many of the cichlids that survived the peak population of Lates are still Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....
and close to extinction.
Systematics and taxonomy
Haplochromis is the type genusType genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
of the tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Haplochromini. Most of the tribe's members were at one time or another included in the present genus, but in many cases this was only temporary. Around the year 1900 as well 100 years later, there was a trend to split
Lumpers and splitters
Lumping and splitting refers to a well-known problem in any discipline which has to place individual examples into rigorously defined categories. The lumper/splitter problem occurs when there is the need to create classifications and assign examples to them, for example schools of literature,...
up the genus; especially in the mid-20th century on the other hand, most authors lumped any and all Haplochromini that were not conspicuously distinct in the type genus.
While a number of African Rift Valley ciclids are certainly very close relatives of H. obliquidens
Haplochromis obliquidens
Haplochromis obliquidens is a species of fish in the Cichlidae family. This is the type species of Haplochromis.It is found in Kenya, Tanzania, and Uganda. Its natural habitat is freshwater lakes. It is not considered a threatened species by the IUCN, but its numbers have declined in recent decade,...
, the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the present genus, it is not very clear where to draw the boundary of Haplochromis with regard to its relatives. Still, several genera are nowadays recognized as distinct by many authors and scientific databases such as FishBase
FishBase
FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...
(see below); in particular the Haplochromini from Lake Tanganyika
Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
and Lake Malawi
Lake Malawi
Lake Malawi , is an African Great Lake and the southernmost lake in the Great Rift Valley system of East Africa. This lake, the third largest in Africa and the eighth largest lake in the world, is located between Malawi, Mozambique, and Tanzania...
are usually removed form Haplochromis. The genus delimitation in the entire tribe remains badly resolved however, and further changes in taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
are likely in the future. In particular between Haplochromis, Astatotilapia
Astatotilapia
Astatotilapia is a genus of haplochromine cichlids from Africa, with a single species in Israel and Syria. Many species have been moved between this genus and Haplochromis, and while some consensus has been reached in recent years, their mutual delimitation is still far from settled.At present,...
and Thoracochromis
Thoracochromis
Thoracochromis is a fish genus of haplochromine cichlids that are endemic to Africa. Most species are from rivers in Angola and Namibia, or the Congo River Basin in Central Africa, but one is from the Nile...
, species have been moved to and fro over the years. The habit of Pseudocrenilabrinae
Pseudocrenilabrinae
The Pseudocrenilabrinae is a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. Previous authors recognized additional African...
to hybridize is hampering molecular phylogenetic studies based on mtDNA alone, while trophic morphs of a single 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...
may appear to be distinct "species" if they are not phylogenetically studied. Several proposed genera are again included in Haplochromis at present, but it cannot be ruled out that some of these will eventually be recognized as valid again.
Species
As of 2009, FishBaseFishBase
FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...
places about 220 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...
in Haplochromis. In addition, there are distinct several populations known which probably represent additional species (see below). The species list here follows FishBase, except for recognizing Pundamilia
Pundamilia
Pundamilia is a small genus of haplochromine cichlids endemic to East Africa, primarily in Lake Victoria. FishBase includes them in Haplochromis while the IUCN treats them as distinct.At present, only four species are placed here:...
as distinct:
Undescribed species
These populations are typically referred to by the names they have in the aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish trade. A number of them is likely to represent undescribed distinct 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...
; others might just be subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
or color morphs. Whether they all belong in Haplochromis is, of course, doubtful. Some of these populations are:
Formerly in Haplochromis
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
of Haplochromini that were formerly included here, many are small or monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
. The distinctness of these is highly doubtful, as they may just be distinct lineages of Haplochromis or other haplochromines. That nonwithstanding, Haplochromini genera to which some former "Haplochromis" have been removed are in particular:
Some other Pseudocrenilabrinae
Pseudocrenilabrinae
The Pseudocrenilabrinae is a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. Previous authors recognized additional African...
were also – mainly by early authors – included in Haplochromis, even though they are not members of its tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
. These are:
- Anomalochromis thomasiAnomalochromis thomasiAnomalochromis thomasi is a species of fish in the family Cichlidae, the only species in the genus Anomalochromis. It is a small cichlid growing to a length of . The natural habitat of A. thomasi is Sierra Leone, Liberia and Guinea, mainly in smaller streams...
of the HemichrominiHemichrominiHemichromini is a tribe of African cichlids.The group consists of 14 species of freshwater fish from two genera: one species in Anomalochromis and the remaining in Hemichromis.-External links:* http://ctdbase.org/detail.go?type=taxon&acc=319076... - Altolamprologus compressicepsAltolamprologus compressicepsAltolamprologus compressiceps is a species of fish in the Cichlidae family. It is found in Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. Its natural habitat is freshwater lakes. It is not considered threatened by the IUCN....
of the LamprologiniLamprologiniLamprologini is a tribe of African cichlid fishes. It contains seven genera and nearly 100 species. Over half of the species in this tribe are in the large genus Neolamprologus. Most genera in the tribe are endemic to Lake Tanganyika, but one species of Neolamprologus Lamprologini is a tribe of... - Tilapia jallae of the Tilapiini
Synonyms of Haplochromis
With all the taxonomic and systematicSystematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
confusion affecting Haplochromis and its allies, it is hardly surprising that the genus has a large number of junior synonyms. Most referred to small or monotypic genera that were once considered distinct, but are nowadays included in Haplochromis again, if only to wait for a major review of their status. Synonyms are:
and sometimes other genera listed above are also synonymized.