Rapid Evolutionary Responses in Cichlids: Genetics of Adaptation, Morphology and Taxonomic Implications

Jacco van Rijssel*, Rob C.M. de Jong, Mary A. Kishes, F. Witte

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterAcademicpeer-review


The haplochromine cichlids of Lake Victoria exhibit the fastest adaptive radiation of vertebrates known. Species identification of these lacustrine cichlids has been subject of debate for many years. Over the past 35 years, environmental perturbations have resulted in phenotypic change and possibly in hybridization, making species delimitation even more problematic. In this chapter, we document the effects of a changed environment on the ecomorphology of the zooplanktivore Haplochromis (Yssichromis) pyrrhocephalus over a 20-year period. We found that this species has extended its habitat to shallower waters and adjusted its diet to larger and more robust prey. Adaptive morphological responses to predation, to larger and tougher prey and to a hypoxic environment were found. Whether these morphological changes are the result of hybridization, phenotypic plasticity or evolutionary adaptation remains unclear. The morphological responses are sometimes so large that they transcend morphological species boundaries and even one of the limits of the genus Yssichromis. The extent of the morphological responses makes clear that nuptial colouration is indispensable for species distinction and the assessment of species richness. We review advanced molecular techniques that might make it possible to distinguish species genetically. These techniques may also reveal how adaptive responses might have played a role in the remarkable resurgence of these rapidly adapting cichlids.
Original languageEnglish
Title of host publicationThe Behavior, Ecology and Evolution of Cichlid Fishes
EditorsM.E. Abate, D.L. Noakes
Place of PublicationDordrecht
ISBN (Electronic)9789402420807
ISBN (Print)9789402420784
Publication statusPublished - 2021

Publication series

NameFish & Fisheries


Dive into the research topics of 'Rapid Evolutionary Responses in Cichlids: Genetics of Adaptation, Morphology and Taxonomic Implications'. Together they form a unique fingerprint.

Cite this