The Cichlids of Lake Malawi – Evolution Happening Today
The cichlids of the lake are divided into two basic groups, loosely referred to as the haplochromines and the tilapiines. Within the first group, Haplochrominae, there are two subgroups. The first one consists of open water and sand dwelling species whose males display bright colors and whose females show a silvery coloration with sometimes irregular black bars or other markings. The second subgroup is known both locally and popularly as mbuna, which means “rockdwellers”. The Mbuna species tend to be smaller, often specialized aufwuchs feeders, and often both sexes are brightly colored with males having several egg shaped gold spots on their anal fin. All haplochromines from Lake Malawi are mouthbrooders.
[youtube:www.youtube.com/watch?v=Rr3UMII0VU8]There are 850 species Malawi cichlid fish with all their own behaviour.
The mbuna fishes display a significant example of biological evolution. Due to the isolation of Lake Malawi from other water bodies, its fish have developed impressive adaptive radiation and speciation, and are an outstanding example of the ecological processes.
Lake Malawi’s cichlids are considered of equal value to science as the finches of the Galapagos Islands remarked on by Charles Darwin or the honeycreepers of Hawaii.
»Lake Malawi National Park
The cichlid fishes of the East African Great Lakes represent an ideal model for the study of parallel evolution. An estimated 660–1,319 species of cichlid fishes have been recorded from Lakes Malawi, Tanganyika, and Victoria, most endemic to a single lake catchment. These species flocks are so rich that, collectively, they provide the best example of rapid adaptive radiation in vertebrates. The independent radiations in the three lakes have produced very similar communities. Many of these species are habitat specialists, with most of them confined either to rocky shores or to sand/mud bottoms (benthic), whereas a few are found in open water (pelagic) habitats. There are several well documented examples of parallel evolution of morphology associated with independent colonization of similar habitats as well as parallel evolution of coloration.
»Parallel life history evolution in mouthbrooding cichlids from the African Great Lakes
* Lake Malawi Cichlid website