Editing Cichlid (section)

==Taxonomy==

=== Internal taxonomy ===
The following consensus taxonomy is based on the [[Eschmeyer's Catalog of Fishes|Catalog of Fishes]] (2025)<ref name=":13">{{Cite web |last=Fricke |first=R. |last2=Eschmeyer |first2=W. N. |last3=Van der Laan |first3=R. |date=2025 |title=ESCHMEYER'S CATALOG OF FISHES: CLASSIFICATION |url=https://www.calacademy.org/eschmeyers-catalog-of-fishes-classification |access-date=2025-02-10 |website=California Academy of Sciences |language=en}}</ref>

* Family '''Cichlidae''' <small>[[Charles Lucien Bonaparte|Bonaparte]], 1835</small>
** Subfamily [[Etroplinae]] <small>Kullander</small><small>, 1998</small> (Indian and Madagascan cichlids)
** Subfamily [[Ptychochrominae]] <small>Sparks</small><small>, 2004</small> (Malagasy cichlids)
** Subfamily [[Pseudocrenilabrinae]] <small>[[Henry Weed Fowler|Fowler]]</small><small>, 1934</small> (African cichlids)
** Subfamily [[Cichlinae]] <small>Bonaparte</small><small>, 1835</small> (American cichlids)

In the past, cichlid taxonomy has varied depending on the author. [[Sven O. Kullander|Kullander]] (1998) recognized eight [[subfamily|subfamilies]] of cichlids: the [[Astronotinae]], [[Cichlasomatinae]], [[Cichlinae]], [[Etroplinae]], [[Geophaginae]], [[Heterochromidinae]], [[Pseudocrenilabrinae]], and [[Retroculinae]].<ref name="Kullander">{{cite book|last=Kullander|first=S.O.|year=1998| chapter=A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes)|pages = 461–498 |editor = L.R. Malabarba |editor2=R.E. Reis |editor3=R.P. Vari |editor4=Z.M. Lucena |editor5=C.A.S. Lucena | title=Phylogeny and classification of neotropical fishes| location= Porto Alegre |publisher = EDIPUCRS | isbn = 978-85-7430-035-1 }}</ref> A ninth subfamily, the [[Ptychochrominae]], was later recognized by Sparks and Smith.<ref name="SparksSmith">{{cite journal |author1=Sparks, J.S.  |author2=Smith, W.L. | year = 2004 | title = Phylogeny and biogeography of cichlid fishes (Teleostei: Perciformes: Cichlidae) | journal = Cladistics | volume = 20 | pages = 501–517 | doi = 10.1111/j.1096-0031.2004.00038.x | issue = 6|pmid=34892958 |citeseerx=10.1.1.595.2118 |s2cid=36086310 }}</ref> Cichlid taxonomy is still debated, and classification of [[genera]] cannot yet be definitively given. A comprehensive system of assigning [[species]] to [[monophyly|monophyletic]] genera is still lacking, and there is not complete agreement on what genera should be recognized in this family.<ref name="Nelson">{{cite book | title = Fishes of the World | last = Nelson | first = Joseph S. | publisher = John Wiley & Sons, Inc. | year = 2006 | isbn = 978-0-471-25031-9}}</ref>

As an example of the classification problems, Kullander<ref>{{Cite web |url=http://www2.nrm.se/ve/pisces/acara/cichphyl.shtml |title=Phylogeny of major groups of cichlids |access-date=10 June 2007 |archive-date=18 January 2012 |archive-url=https://web.archive.org/web/20120118213155/http://www2.nrm.se/ve/pisces/acara/cichphyl.shtml |url-status=dead }}</ref> placed the African genus ''[[Heterochromis]]'' [[phylogenetic]]ally within [[Neotropical]] cichlids, although later papers{{citation needed|date=December 2019}} concluded otherwise. Other problems center upon the identity of the putative common ancestor for the Lake Victoria superflock (many closely related species sharing a single habitat), and the ancestral lineages of Lake Tanganyikan cichlids.{{citation needed|date=December 2019}}
[[File:Aequidens pallidus MH-MCZArtwork ARC 209-201.jpg|alt=A 19th century watercolor painting of a pale flag cichlid.|thumb|A 19th century watercolor painting of a pale flag cichlid by Jacques Burkhardt.|left]]
Phylogeny derived from morphological characters shows differences at the genus level with phylogeny based on [[Locus (genetics)|genetic loci]].<ref>{{cite journal |last1=Streelman |first1=J.T. |last2=Zardoya |first2=R. |last3=Meyer |first3=A. |last4=Karl |first4=S. A. |date=1 July 1998 |title=Multilocus phylogeny of cichlid fishes (Pisces: Perciformes): evolutionary comparison of microsatellite and single-copy nuclear loci. |journal=Molecular Biology and Evolution |volume=15 |issue=7 |pages=798–808 |doi=10.1093/oxfordjournals.molbev.a025985 |pmid=10766579 |doi-access=free}}</ref> A consensus remains that the Cichlidae as a family are monophyletic.<ref>{{cite journal |last1=Salzburger |first1=Walter |last2=Meyer |first2=Axel |date=June 2004 |title=The species flocks of East African cichlid fishes: Recent advances in molecular phylogenetics and population genetics |journal=Naturwissenschaften |volume=91 |issue=6 |pages=277–90 |doi=10.1007/s00114-004-0528-6 |pmid=15241604 |bibcode=2004NW.....91..277S |s2cid=5816449 |url=http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-32995 }}</ref>

In cichlid taxonomy, [[dentition]] was formerly used as a classifying characteristic, but this was complicated because in many cichlids, tooth shapes change with age, due to wear, and cannot be relied upon. [[DNA sequencing|Genome sequencing]] and other technologies transformed cichlid taxonomy.

Alternatively, all cichlid species native to the [[New World]], can be classified under the subfamily Cichlinae, while Etroplinae can classify all cichlid species native to the [[Old World]].

=== External taxonomy ===
The taxonomic placement of cichlids has long been disputed and variable, and has only recently been largely resolved. In the past, based on morphological characteristics, cichlids were classed in a suborder, the [[Labroidei]], along with the wrasses ([[Labridae]]), in the order [[Perciformes]].<ref name="Stiassny">{{cite journal |author1=Stiassny, M.L.J. |author2=Jensen, J.S. |year=1987 |title=Labroid intrarelationships revisited: morphological complexity, key innovations, and the study of comparative diversity |journal=Bulletin of the Museum of Comparative Zoology |volume=151 |pages=269–319}}</ref> However, studies incorporating [[molecular phylogenetics]] have contradicted this grouping.<ref>{{cite journal |last1=Wainwright |first1=Peter C. |display-authors=etal |year=2012 |title=The evolution of pharyngognathy: A phylogenetic and functional appraisal of the pharyngeal jaw key innovation in labroid fishes and beyond |journal=[[Systematic Biology]] |volume=61 |issue=6 |pages=1001–1027 |doi=10.1093/sysbio/sys060 |pmid=22744773 |doi-access=free}}</ref> 

More recent phylogenetic studies support the creation of a distinct order, the [[Cichliformes]], to contain the cichlids and their close relatives, which are no longer thought to be closely related to wrasses. The closest living relative of cichlids has been found to be the marine [[Pholidichthys leucotaenia|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]].<ref name="Nelson5">{{cite book |author1=Nelson, J.S. |url=https://sites.google.com/site/fotw5th/ |title=Fishes of the World |author2=Grande, T.C. |author3=Wilson, M.V.H. |publisher=Wiley |year=2016 |isbn=978-1-118-34233-6 |edition=5th |pages=752 |access-date=5 November 2018 |archive-url=https://web.archive.org/web/20190408194051/https://sites.google.com/site/fotw5th/ |archive-date=8 April 2019 |url-status=dead}}</ref> The [[Eschmeyer's Catalog of Fishes|Catalog of Fishes]] adopts the same placement, although the [[Polycentridae|leaffishes]] (which have a similar African and South American distribution) are now also placed in the Cichliformes.<ref name=":12">{{Cite web |last1=Fricke |first1=R. |last2=Eschmeyer |first2=W. N. |last3=Van der Laan |first3=R. |date=2025 |title=ESCHMEYER'S CATALOG OF FISHES: CLASSIFICATION |url=https://www.calacademy.org/eschmeyers-catalog-of-fishes-classification |access-date=2025-02-10 |website=California Academy of Sciences |language=en}}</ref> Although these interrelationships are now generally well-supported, other authors have interpreted these relationships in differing ways, such as instead placing the cichlids, leaffish, and convict blenny as the most basal members of an expanded [[Blenniiformes]].<ref>{{Cite journal |last1=Near |first1=Thomas J. |last2=Thacker |first2=Christine E. |date=2024-04-18 |title=Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii) |url=https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-65/issue-1/014.065.0101/Phylogenetic-Classification-of-Living-and-Fossil-Ray-Finned-Fishes-Actinopterygii/10.3374/014.065.0101.full |journal=Bulletin of the Peabody Museum of Natural History |volume=65 |issue=1 |page=101 |doi=10.3374/014.065.0101 |bibcode=2024BPMNH..65..101N |issn=0079-032X}}</ref>

=== Evolution ===
Modern cichlids have a [[disjunct distribution]] consisting of Africa (including [[Madagascar]]), the [[Neotropical realm|Neotropics]] (including [[Cuba]] and [[Hispaniola]]), the [[Levant]], southern Iran, and the southern [[Indian subcontinent]]. This distribution has become the subject of much scientific dispute, with it being debated whether modern cichlid distribution is a consequence of the breakup of [[Gondwana]] (which would make cichlids a particularly ancient group dating to the [[Early Cretaceous]]), or if it is instead based on more recent [[oceanic dispersal]] by the cichlids (despite modern members of the group being largely restricted to freshwater).<ref name=":2">{{cite journal |last1=Chakrabarty |first1=Prosanta |date=June 2004 |title=Cichlid biogeography: comment and review |journal=Fish and Fisheries |volume=5 |issue=2 |pages=97–119 |bibcode=2004AqFF....5...97C |doi=10.1111/j.1467-2979.2004.00148.x |hdl-access=free |hdl=2027.42/72313}}</ref>

Proponents of the Gondwanan theory, which saw more support in the past, have noted that the cichlids display the precise [[Sister group|sister relationships]] predicted by [[Gondwanan distribution]]: Africa-South America and India-Madagascar, and that with the exception of the species from Cuba, Hispaniola and Madagascar, cichlids have not reached any oceanic island. The dispersal hypothesis, in contrast, requires cichlids to have negotiated thousands of kilometers of open ocean between India and Madagascar without colonizing any other island, or for that matter, crossing the [[Mozambique Channel]] to Africa.<ref name=":2" />

However, more recent studies incorporating phylogenetic evidence have found that the divergences within the cichlids are far too young for cichlids to have even been present for the breakup of Gondwana. [[Molecular clock]] estimates have placed the family's origin only to the [[Maastrichtian|Late Cretaceous]] period, and the divergences within the family to have occurred anywhere between the Late Cretaceous to the [[Eocene]] (depending on the study). This suggests that only dispersal can support modern cichlid distribution. However, the factors that may have allowed prehistoric cichlids to make migrations over entire oceans remains a mystery.<ref name="Rican2013" /><ref>{{Cite journal |last=Matschiner |first=Michael |date=2019-04-01 |title=Gondwanan vicariance or trans-Atlantic dispersal of cichlid fishes: a review of the molecular evidence |url=https://link.springer.com/article/10.1007/s10750-018-3686-9 |journal=Hydrobiologia |language=en |volume=832 |issue=1 |pages=9–37 |doi=10.1007/s10750-018-3686-9 |bibcode=2019HyBio.832....9M |issn=1573-5117|url-access=subscription }}</ref><ref>{{Cite journal |last1=Matschiner |first1=Michael |last2=Böhne |first2=Astrid |last3=Ronco |first3=Fabrizia |last4=Salzburger |first4=Walter |date=2020-11-18 |title=The genomic timeline of cichlid fish diversification across continents |url=https://link.springer.com/article/10.1038/s41467-020-17827-9?fromPaywallRec=true |journal=Nature Communications |language=en |volume=11 |issue=1 |pages=5895 |doi=10.1038/s41467-020-17827-9 |bibcode=2020NatCo..11.5895M |issn=2041-1723|hdl=10852/83721 |hdl-access=free }}</ref><ref name=":3">{{Cite journal |last1=Friedman |first1=Matt |last2=Keck |first2=Benjamin P. |last3=Dornburg |first3=Alex |last4=Eytan |first4=Ron I. |last5=Martin |first5=Christopher H. |last6=Hulsey |first6=C. Darrin |last7=Wainwright |first7=Peter C. |last8=Near |first8=Thomas J. |date=2013-11-07 |title=Molecular and fossil evidence place the origin of cichlid fishes long after Gondwanan rifting |journal=Proceedings of the Royal Society B: Biological Sciences |volume=280 |issue=1770 |pages=20131733 |doi=10.1098/rspb.2013.1733 |pmc=3779330 |pmid=24048155}}</ref> It is known that during the [[Paleogene]], the [[Atlantic Ocean]] between South America and Africa was significantly narrower, and it has been suggested that either now-submerged islands or a large [[River plume|plume]] from the [[Congo River]] may have allowed for a shallower or less saline environment that was conducive for cichlids to disperse from Africa to South America. Under the dispersal hypothesis, it is generally accepted that Africa was the ancestral home for cichlids, from which they dispersed to attain their present distribution.<ref name=":3" />

=== Fossil record ===
[[File:Warilochromis skeleton.png|thumb|''[[Warilochromis]]'', a fossil cichlid from the [[Miocene]] of Kenya]]
The fossil record of cichlids is comprehensive, although it only starts in the [[Eocene]], well after the family is thought to have undergone significant evolutionary diversification. Fossil cichlids appear in both South America and Africa at roughly the same time in the Eocene, with fossil cichlids known from the [[Early Eocene]] (48.6&nbsp;[[Million years ago|mya]])-aged [[Lumbrera Formation]] of [[Argentina]],<ref name="M14">{{cite journal |last1=Malabarba |first1=Maria C. |last2=Malabarba |first2=Luiz R. |last3=López-Fernández |first3=Hernán |year=2014 |title=On the Eocene cichlids from the Lumbrera Formation: additions and implications for the Neotropical ichthyofauna |journal=Journal of Vertebrate Paleontology |volume=34 |issue=1 |pages=49–58 |bibcode=2014JVPal..34...49M |doi=10.1080/02724634.2013.830021}}</ref> as well as the Middle Eocene (46 mya)-aged [[Mahenge Formation]] of [[Tanzania]],<ref name=":4">{{Cite journal |last=Murray |first=Alison M. |date=2001-01-19 |title=Eocene cichlid fishes from Tanzania, East Africa |url=https://www.tandfonline.com/doi/abs/10.1671/0272-4634(2000)020%5B0651:ECFFTE%5D2.0.CO;2 |journal=Journal of Vertebrate Paleontology |volume=20 |issue=4 |pages=651–664 |doi=10.1671/0272-4634(2000)020[0651:ECFFTE]2.0.CO;2 |issn=0272-4634|url-access=subscription }}</ref> suggesting that the divergence between Old and New World cichlids must have occurred prior to this point.

Several African fossil sites that contain cichlids (including the Eocene-aged Mahenge Formation of Tanzania and the Miocene-aged [[Ngorora Formation]] of Kenya)<ref name=":5">{{Cite journal |last1=Penk |first1=Stefanie B. R. |last2=Altner |first2=Melanie |last3=F. Cerwenka |first3=Alexander |last4=Schliewen |first4=Ulrich K. |last5=Reichenbacher |first5=Bettina |date=2019-07-15 |title=New fossil cichlid from the middle Miocene of East Africa revealed as oldest known member of the Oreochromini |journal=Scientific Reports |language=en |volume=9 |issue=1 |pages=10198 |doi=10.1038/s41598-019-46392-5 |pmid=31308387 |pmc=6629881 |bibcode=2019NatSR...910198P |issn=2045-2322}}</ref> appear to represent former [[Maar|maars]] or [[Rift lake|rift lakes]], and the fossil cichlids present in them appear to represent [[Species flock|species flocks]] akin to those in the modern [[Rift Valley lakes|African rift lakes]]. This suggests that rapid diversification within enclosed ecosystems is a longstanding trait of cichlids.<ref name=":4" /><ref name=":5" />

Fossil remains also suggest that cichlids ranged further north in the geologic past, with the extinct [[tilapia]] ''[[Oreochromis lorenzoi]]'' being known from the [[Late Miocene]] of Italy.<ref name=":02">{{Cite journal |last1=Carnevale |first1=Giorgio |last2=Sorbini |first2=Chiara |last3=Landini |first3=Walter |date=2003-09-12 |title=Oreochromis lorenzoi, a new species of tilapiine cichlid from the late Miocene of central Italy |url=https://www.tandfonline.com/doi/abs/10.1671/1858 |journal=Journal of Vertebrate Paleontology |volume=23 |issue=3 |pages=508–516 |doi=10.1671/1858 |bibcode=2003JVPal..23..508C |issn=0272-4634|url-access=subscription }}</ref>