Haplochromis


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, already established in 1814, and was abolished. As the years went by, other genera of Haplochromini were lumped with and split again from Haplochromis, and the final delimitation of the clade around H. obliquidens is not yet done.

Extinction crisis in Lake Victoria

The introduction of Nile perch 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, 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 may have 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. The entire trophic web has been observed to be upset. But still, evolution runs its course: those Lake Victoria Haplochromis species 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.

Systematics and taxonomy

Haplochromis is the type genus 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, the trend was 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 cichlids 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 now recognized as distinct by many authors and scientific databases, such as FishBase ; in particular the Haplochromini from Lake Tanganyika and Lake Malawi are usually removed from 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 from 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.

Species

There are currently 227 recognized species in this genus:Haplochromis acidens Greenwood, 1967Haplochromis adolphifrederici Boulenger, 1914Haplochromis aelocephalus Greenwood, 1959Haplochromis aeneocolor Greenwood, 1973Haplochromis akika Lippitsch, 2003Haplochromis albertianus Regan, 1929Haplochromis altigenis Regan, 1922Haplochromis ampullarostratus Schraml, 2004Haplochromis angustifrons Boulenger, 1914Haplochromis annectidens Trewavas, 1933Haplochromis antleter Mietes & F. Witte, 2010 Haplochromis apogonoides Greenwood, 1967Haplochromis arcanus Greenwood & Gee, 1969Haplochromis argens de Zeeuw, Westbroek & F. Witte, 2013Haplochromis argenteus Regan, 1922Haplochromis artaxerxes Greenwood, 1962Haplochromis astatodon Regan, 1921Haplochromis avium Regan, 1929Haplochromis barbarae Greenwood, 1967Haplochromis bareli van Oijen, 1991Haplochromis bartoni Greenwood, 1962Haplochromis bayoni Boulenger, 1909Haplochromis beadlei Trewavas, 1933Haplochromis bicolor Boulenger, 1906Haplochromis bloyeti Haplochromis boops Greenwood, 1967Haplochromis brownae Greenwood, 1962Haplochromis bullatus Trewavas, 1938Haplochromis bwathondii Niemantsverdriet & F. Witte, 2010 Haplochromis cassius Greenwood & Barel, 1978Haplochromis cavifrons Hilgendorf, 1888Haplochromis chilotes Boulenger, 1911Haplochromis chlorochrous Greenwood & Gee, 1969Haplochromis chromogynos Greenwood, 1959Haplochromis chrysogynaion van Oijen, 1991Haplochromis cinctus Greenwood & Gee, 1969 Haplochromis cinereus Boulenger, 1906Haplochromis cnester F. Witte & Witte-Maas, 1981Haplochromis commutabilis Schraml, 2004 Haplochromis coprologus Niemantsverdriet & F. Witte, 2010 Haplochromis crassilabris Boulenger, 1906Haplochromis crebridens Snoeks, De Vos, Coenen & Thys van den Audenaerde, 1990Haplochromis crocopeplus Greenwood & Barel, 1978Haplochromis cronus Greenwood, 1959Haplochromis cryptodon Greenwood, 1959Haplochromis cryptogramma Greenwood & Gee, 1969Haplochromis cyaneus Seehausen, Bouton & Zwennes, 1998Haplochromis decticostoma Greenwood & Gee, 1969Haplochromis degeni Boulenger, 1906Haplochromis dentex Regan, 1922Haplochromis dichrourus Regan, 1922Haplochromis diplotaenia Regan & Trewavas, 1928Haplochromis dolichorhynchus Greenwood & Gee, 1969Haplochromis dolorosus Trewavas, 1933Haplochromis eduardianus Boulenger, 1914Haplochromis eduardii Regan, 1921Haplochromis elegans Trewavas, 1933Haplochromis empodisma Greenwood, 1960Haplochromis engystoma Trewavas, 1933Haplochromis erythrocephalus Greenwood & Gee, 1969Haplochromis erythromaculatus De Vos, Snoeks & Thys van den Audenaerde, 1991Haplochromis estor Regan, 1929 Haplochromis eutaenia Regan & Trewavas, 1928Haplochromis exspectatus Schraml, 2004Haplochromis fischeri Seegers, 2008Haplochromis flavipinnis Boulenger, 1906Haplochromis flavus Seehausen, Zwennes & Lippitsch, 1998Haplochromis fuelleborni Hilgendorf & Pappenheim, 1903 Haplochromis fuscus Regan, 1925Haplochromis fusiformis Greenwood & Gee, 1969Haplochromis gigliolii Pfeffer, 1896Haplochromis gilberti Greenwood & Gee, 1969Haplochromis goldschmidti F. Witte, Westbroek & de Zeeuw, 2013Haplochromis gowersii Trewavas, 1928Haplochromis gracilior Boulenger, 1914 Haplochromis granti Boulenger, 1906Haplochromis graueri Boulenger, 1914Haplochromis guiarti Pellegrin, 1904Haplochromis harpakteridion van Oijen, 1991Haplochromis heusinkveldi F. Wittee & Witte-Maas, 1987Haplochromis hiatus Hoogerhoud & F. Witte, 1981Haplochromis howesi van Oijen, 1992Haplochromis humilior Boulenger, 1911Haplochromis humilis Steindachner, 1866Haplochromis insidiae Snoeks, 1994Haplochromis iris Hoogerhoud & F. Witte, 1981Haplochromis ishmaeli Boulenger, 1906Haplochromis kamiranzovu Snoeks, Coenen & Thys van den Audenaerde, 1984Haplochromis katavi Seegers, 1996 Haplochromis katonga Schraml & Tichy, 2010Haplochromis katunzii ter Huurne & F. Witte, 2010 Haplochromis kujunjui van Oijen, 1991Haplochromis labiatus Trewavas, 1933Haplochromis labriformis Nichols & La Monte, 1938Haplochromis lacrimosus Boulenger, 1906Haplochromis laparogramma Greenwood & Gee, 1969Haplochromis latifasciatus Regan, 1929Haplochromis limax Trewavas, 1933Haplochromis lividus Greenwood, 1956Haplochromis loati Greenwood, 1971Haplochromis longirostris Hilgendorf, 1888Haplochromis luluae Haplochromis nuchisquamulatus Hilgendorf, 1888Haplochromis nyanzae Greenwood, 1962Haplochromis obesus Boulenger, 1906Haplochromis obliquidens Hilgendorf, 1888Haplochromis obtusidens Trewavas, 1928Haplochromis occultidens Snoeks, 1988Haplochromis oligolepis Lippitsch, 2003Haplochromis olivaceus Snoeks, De Vos, Coenen & Thys van den Audenaerde, 1990Haplochromis oregosoma Greenwood, 1973Haplochromis orthostoma Regan, 1922Haplochromis pachycephalus Greenwood, 1967Haplochromis pallidus Boulenger, 1911Haplochromis paludinosus fHaplochromis pancitrinus Mietes & F. Witte, 2010 Haplochromis pappenheimi Boulenger, 1914Haplochromis paradoxus Lippitsch & Kaufman, 2003Haplochromis paraguiarti Greenwood, 1967Haplochromis paraplagiostoma Greenwood & Gee, 1969Haplochromis paropius Greenwood & Gee, 1969Haplochromis parorthostoma Greenwood, 1967Haplochromis parvidens Boulenger, 1911Haplochromis paucidens Regan, 1921Haplochromis pellegrini Regan, 1922Haplochromis percoides Boulenger, 1906Haplochromis perrieri Pellegrin, 1909Haplochromis petronius Greenwood, 1973Haplochromis pharyngalis Poll & Damas, 1939Haplochromis pharyngomylus Regan, 1929Haplochromis phytophagus Greenwood, 1966Haplochromis piceatus Greenwood & Gee, 1969Haplochromis pitmani Fowler, 1936 Haplochromis placodus Poll & Damas, 1939Haplochromis plagiodon Regan & Trewavas, 1928Haplochromis plagiostoma Regan, 1922Haplochromis plutonius Greenwood & Barel, 1978Haplochromis prodromus Trewavas, 1935Haplochromis prognathus Pellegrin, 1904Haplochromis pseudopellegrini Greenwood, 1967Haplochromis ptistes Greenwood & Barel, 1978Haplochromis pyrrhocephalus F. Witte & Witte-Maas, 1987Haplochromis pyrrhopteryx van Oijen, 1991Haplochromis retrodens Hilgendorf, 1888Haplochromis riponianus Boulenger, 1911Haplochromis rubescens Snoeks, 1994Haplochromis rubripinnis Seehausen, Lippitsch & Bouton, 1998Haplochromis rudolfianus Trewavas, 1933Haplochromis rufus Seehausen & Lippitsch, 1998Haplochromis sauvagei Pfeffer, 1896Haplochromis saxicola Greenwood, 1960Haplochromis scheffersi Snoeks, De Vos & Thys van den Audenaerde, 1987Haplochromis schubotzi Boulenger, 1914Haplochromis schubotziellus Greenwood, 1973Haplochromis serranus Pfeffer, 1896Haplochromis serridens Regan, 1925Haplochromis simpsoni Greenwood, 1965Haplochromis smithii Castelnau, 1861Haplochromis snoeksi Wamuini Lunkayilakio & Vreven, 2010 Haplochromis spekii Boulenger, 1906Haplochromis sphex ter Huurne & F. Witte, 2010 Haplochromis squamipinnis Regan, 1921Haplochromis squamulatus Regan, 1922Haplochromis sulphureus Greenwood & Barel, 1978Haplochromis tanaos van Oijen & F. Witte, 1996Haplochromis taurinus Trewavas, 1933Haplochromis teegelaari Greenwood & Barel, 1978Haplochromis teunisrasi F. Witte & Witte-Maas, 1981Haplochromis theliodon Greenwood, 1960Haplochromis thereuterion van Oijen & F. Witte, 1996Haplochromis thuragnathus Greenwood, 1967Haplochromis tridens Regan & Trewavas, 1928Haplochromis turkanae Greenwood, 1974 Haplochromis tyrianthinus Greenwood & Gee, 1969Haplochromis ushindi van Oijen, 2004Haplochromis vanheusdeni F. D. B. Schedel, Friel & U. K. Schliewen, 2014 Haplochromis vanoijeni de Zeeuw & F. Witte, 2010 Haplochromis velifer Trewavas, 1933Haplochromis venator Greenwood, 1965Haplochromis vicarius Trewavas, 1933Haplochromis victoriae Greenwood, 1956Haplochromis victorianus Pellegrin, 1904Haplochromis vittatus Boulenger, 1901Haplochromis vonlinnei van Oijen & de Zeeuw, 2008 Haplochromis welcommei Greenwood, 1966Haplochromis worthingtoni Regan, 1929Haplochromis xanthopteryx Seehausen & Bouton, 1998Haplochromis xenognathus Greenwood, 1957Haplochromis xenostoma Regan, 1922

Undescribed species

These populations are typically referred to by the names they have in the aquarium fish trade. A number of them are 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:Haplochromis sp. '75'

Formerly in ''Haplochromis''

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:Astatoreochromis Astatotilapia Aulonocara Buccochromis Caprichromis Champsochromis Cheilochromis Chetia Copadichromis Ctenochromis Ctenopharynx Cyrtocara Dimidiochromis Eclectochromis Fossorochromis Hemitaeniochromis Lethrinops Maylandia/Metriaclima Mbipia Mchenga Melanochromis Mylochromis Naevochromis Neochromis Nimbochromis Nyassachromis Orthochromis Otopharynx Pharyngochromis Placidochromis Protomelas Pundamilia Pseudocrenilabrus Sargochromis Schwetzochromis Sciaenochromis Shuja Stigmatochromis Taeniochromis Taeniolethrinops Thoracochromis Tramitichromis Trematocranus Tyrannochromis
Some other Pseudocrenilabrinae were also – mainly by early authors – included in Haplochromis, though they are not members of its tribe. These are:Anomalochromis thomasi of the HemichrominiAltolamprologus compressiceps of the LamprologiniTilapia jallae of the Tilapiini

Synonyms of ''Haplochromis''

With all the taxonomic and systematic 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 now included in Haplochromis again, if only to wait for a major review of their status. Synonyms are:Allochromis Greenwood, 1980Cleptochromis Greenwood, 1980Enterochromis Greenwood, 1980Gaurochromis Greenwood, 1980Harpagochromis Greenwood, 1980Labrochromis Regan, 1920Lipochromis Regan, 1920Platytaeniodus Boulenger, 1906Prognathochromis Greenwood, 1980Ptyochromis Greenwood, 1980Psammochromis Greenwood, 1980Tridontochromis Greenwood, 1980Xystichromis Greenwood, 1980Yssichromis Greenwood, 1980
Sometimes other genera listed above are also synonymized.