What Is a Cichlid?
hat is a Cichlid? Cichlids ("sick-lids") are, by vertebrate standards, a very large family of freshwater, perchlike fishes with perhaps more than 1,500 species. (The cichlid in the photo above is Tyrannochromis polyodon, a predatory species from Lake Malawi.) Of all the species of vertebrates, more than 5% are cichlids. They live primarily in the lands that formed part of Gondwana, the huge former southern supercontinent where they first evolved before its break-up >150 million years ago and probably differentiated into the major lineages 70-95 million years ago (Zardoya et al., 1996). These lands include Madagascar, India, Africa, and South America. Secondarily, cichlids have dispersed into a few more northerly lands Central America, the Middle East, and southern Iran that were part of Laurasia, the huge former northern supercontinent.
Examples of New World cichlids that are familiar to many people as aquarium fish are the Firemouth, the Oscar, the Jack Dempsey, the Discus, and the freshwater Angelfish. Tilapias are Old World cichlids that are important as wild or pond-raised food fish in the tropics and, increasingly, in subtropical and even temperate climes. Most cichlids, though, live in the large species flocks in the African Great Lakes, especially lakes Tanganyika, Victoria, and with the largest flock of all Malawi.
Cichlids are highly diverse in maximum size, coloration, behavior, and ecology. Thus, they are not easy to characterize. However, after some practice, they usually have a recognizable "look." It is clear, nevertheless, that cichlids are a natural, monophyletic group because they possess a number of unique anatomical specializations. Cichlids are believed to be most closely related to the salt-water surfperches, damselfishes, wrasses, odacids, and parrotfishes, all of which together with cichlids constitute the percomorph suborder Labroidei (Stiassny, 1991).
An excellent, easily understandable, more complete introduction to cichlids is available at Dr. Ron Coleman's Cichlid Research Home Page.
|Last Update: 21 June 2000
Web Author: M. K. Oliver, Ph.D.
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