Editing Cichlid (section)

=== 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}}</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" />