Editing Lake Malawi (section)

====Cichlids====

Lake Malawi is noted for being the site of [[evolutionary radiation]]s among several groups of animals, most notably [[cichlid]] fish.<ref>{{cite journal | last=Svardal | first=Hannes | last2=Quah | first2=Fu Xiang | last3=Malinsky | first3=Milan | last4=Ngatunga | first4=Benjamin P | last5=Miska | first5=Eric A | last6=Salzburger | first6=Walter | last7=Genner | first7=Martin J | last8=Turner | first8=George F | last9=Durbin | first9=Richard | title=Ancestral Hybridization Facilitated Species Diversification in the Lake Malawi Cichlid Fish Adaptive Radiation | journal=Molecular Biology and Evolution | volume=37 | issue=4 | date=2020-04-01 | issn=0737-4038 | pmid=31821500 | pmc=7086168 | doi=10.1093/molbev/msz294 | pages=1100–1113|biorxiv=10.1101/738633|s2cid=202010546|hdl=1983/40d3dafd-f1d5-4ea4-a447-126df76a0651|hdl-access=free}}</ref> There are at least 700 cichlid species in Lake Malawi,<ref name=Turner2001/> with some estimating that the actual figure is as high as 1,000 species.<ref name=panda/><ref>Kornfield, I.; & P.F. Smith (2000). African Cichlid Fishes: Model Systems for Evolutionary Biology. Annual Review of Ecology and Systematics 31: 163–196. [[doi: 10.1146/annurev.ecolsys.31.1.163]].</ref> The actual number is labelled with some uncertainty because of the many [[undescribed species]] and the extreme variation among some species, making the task of delimiting them very complex.<ref name=Turner2001/><ref name=Konings/> Except for four species (''[[Astatotilapia calliptera]]'', ''[[Coptodon rendalli]]'', ''Oreochromis shiranus'' and ''[[Serranochromis]] robustus''), all cichlids in the lake are [[Endemism|endemic]] to the Malawi system, which also includes nearby smaller [[Lake Malombe]] and the upper Shire River.<ref name=Konings/><ref name=OliverTilapia>Oliver, M.K. (12 April 2015). [http://malawicichlids.com/mw10100.htm The Tilapias of Lake Malawi.] MalawiCichlids. Retrieved 13 April 2017.</ref><ref>Oliver, M.K. (12 April 2015). [http://malawicichlids.com/mw10000.htm The Nonendemic Haplochromine Cichlids of Lake Malawi.] MalawiCichlids. Retrieved 13 April 2017.</ref> Many of these have become popular among [[aquarium]] owners due to their bright colors. Recreating a Lake Malawi biotope to host cichlids became quite popular in the aquarium hobby.<ref>{{cite web|last1=Pardee|first1=Keith|title=African Cichlids, Lake Malawi|url=http://www.aquariumlife.net/profiles/african-cichlids-lake-malawi|website=www.aquariumlife.net|access-date=30 September 2017|language=en|archive-url=https://web.archive.org/web/20171012113129/http://www.aquariumlife.net/profiles/african-cichlids-lake-malawi|archive-date=12 October 2017|url-status=dead}}</ref> Most Malawi cichlids are found in relatively shallow coastal waters,<ref name=Konings/> but ''[[Diplotaxodon]]'' has been recorded down to depths of {{convert|200-220|m|ft|abbr=on}} and several (especially ''Diplotaxodon'', ''[[Rhamphochromis]]'' and ''[[Copadichromis quadrimaculatus]]'') are known from [[pelagic]] waters.<ref name=Lowe2003/>

The cichlids of the lake are divided into two groups and the vast majority of the species are [[haplochromines]]. The [[sister species]] to the Malawi haplochromines is ''Astatotilapia'' sp. Ruaha (a currently undescribed species from [[Great Ruaha River]]), and these two separated between 2.13 and 6.76 million years ago (mya).<ref name=Genner2015>Genner; Ngatunga; Mzighani; Smith; and Turner (2015). Geographical ancestry of Lake Malawi’s cichlid fish diversity. Biol. Lett. 11: 2015023. {{doi|10.1098/rsbl.2015.0232}}</ref> The earliest divergence within the Malawi haplochromines occurred between 1.20 and 4.06 mya,<ref name=Genner2015/> but most radiations in this group are far younger; in extreme cases species may have diverged only a few hundred years ago.<ref name=Givnish1997/> The Malawi haplochromines are [[mouthbrooder]]s, but otherwise vary extensively in general behaviour and ecology.<ref name=Konings/> Within the Malawi haplochromines there are two main groups, the haps and the [[mbuna]]. The haps (they were formerly included in ''[[Haplochromis]]'') can be further subdivided into three subgroups: The relatively large, often more than {{convert|20|cm|in|abbr=on|0}} long, and aggressive [[piscivore]]s that roam various habitats in pursuit of prey, the open-water (although often not far from sand or rocks) [[utaka]] that feed in [[Shoaling and schooling|schools]] on [[zooplankton]] and typically are of medium size, and finally a subgroup of "aberrant" species that essentially are defined by them not fitting clearly into the other subgroups.<ref name=Konings/><ref name=Elieson>Elieson, M: [http://www.cichlid-forum.com/articles/haps_vs_mbuna.php Haps Vs. Mbuna.] Retrieved 11 April 2017.</ref><ref name=aquaticcom>Aquaticcommunity (2004–08).[http://www.aquaticcommunity.com/cichlid/haplochromis.php Haplochromis.] Retrieved 13 April 2017.</ref> Adult male haps generally display bright colors, while juveniles of both sexes and adult females typically show a silvery or grey coloration with sometimes irregular black bars or other markings.<ref name=Konings/><ref name=Elieson/> The second main haplochromine group are the mbuna, a name used both locally and popularly, which means "rockfish" in [[Tonga (Nyasa) language|Tonga]].<ref>Loiselle, P.V. (1988). A Fishkeepers Guide to African Cichlids, p. 97. Salamander Books, London & New York. {{ISBN|0-86101-407-3}}.</ref> They are found at rocky outcrops, [[Territory (animal)|territorially]] aggressive (although commonly found in high densities) and often specialised [[aufwuchs]] feeders.<ref name=Konings/><ref name=Elieson/> The mbuna species tend to be relatively small, mostly less than {{convert|13|cm|in|abbr=on|0}} long, and often both sexes are brightly colored with males having egg-shaped yellow spots on their [[anal fin]] (a feature particularly prevalent in the mbuna, but not exclusive to this group).<ref name=Konings/><ref name=Elieson/>

The second group, the [[tilapia]], comprises only six species in two genera in Lake Malawi: The [[redbreast tilapia]] (''Coptodon rendalli''), a widespread African species, is the only substrate-spawning cichlid in the lake.<ref name=Konings/><ref>Oliver, M.K. (12 April 2015). [http://malawicichlids.com/mw10003.htm Coptodon rendalli.] Malawicichlids. Retrieved 13 April 2017.</ref> This large cichlid mainly feeds on [[macrophyte]]s.<ref name=Konings/><ref>{{FishBase species | genus = Coptodon | species = rendalli | month = April| year = 2017}}</ref> The remaining are five mouthbrooding species of ''[[Oreochromis]]''; four chambo in the subgenus ''Nyasalapia'' (''O. karongae'', ''O. lidole'', ''O. saka'' and ''O. squamipinnis'') that are endemic to the Lake Malawi system, as well as the closely related ''O. shiranus'', which also is found in [[Lake Chilwa]].<ref name=Konings/><ref name=Turner1992/><ref name=OliverTilapia/> The Malawi ''Oreochromis'' mainly feed on [[phytoplankton]], reach lengths up to {{convert|26-42|cm|in|abbr=on}} depending on the exact species, and are mostly black or silvery-gray with relatively indistinct dark bars.<ref name=Konings/><ref name=OliverTilapia/><ref>{{FishBase genus | genus = Oreochromis | month = April| year = 2017}}</ref> Male chambo have unique genital tassels when breeding, which aid in egg fertilisation in a manner comparable to the egg-spots on the anal fin of haplochromines.<ref name=Konings/><ref name=Turner1992/>