The Cichlid Fishes of Lake Malawi, Africa

Abstract of Publication

Reinthal, P.N. [1990a]. The gross intestine morphology of a group of rock-dwelling cichlid fishes (Pisces, Teleostei) from Lake Malawi. Netherlands Journal of Zoology 39 (3-4) 1989: 208-225.  

Length and coiling patterns of the gastrointestinal tract of a group of rock-dwelling cichlid fishes (the 'mbuna') from Lake Malawi, Africa are reported in this study. In the 16 species of primarily herbivorous fish examined, diet and habitat correlated with gut length. Species feeding primarily on diatoms in sediment-rich environments have longer intestines than those feeding on more animal material or in sediment-free environments. The coiling pattern of the gastrointestinal tract is equivalent for all species and does not appear to be taxonomically useful within the group. If intestine length is responsive, in either ecological or evolutionary time scales, to changes in diet, this permits flexibility in the range of dietary items that a particular individual or lineage may consume. Structural specializations, such as intestine morphology, promoting differential resource utilization characterize the adaptive radiation of the family Cichlidae and facilitate ecological coexistence in these high diversity assemblages.




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