Lake Malawi cichlid evolution along a benthic/limnetic axis
Article first published online: 7 JUN 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Ecology and Evolution
Volume 3, Issue 7, pages 2262–2272, July 2013
How to Cite
Ecology and Evolution 2013; 3(7): 2262–2272
- Issue published online: 10 JUL 2013
- Article first published online: 7 JUN 2013
- Manuscript Accepted: 9 MAY 2013
- Manuscript Revised: 8 MAY 2013
- Manuscript Received: 13 MAR 2013
- National Science Foundation. Grant Number: IOS 0546423
- Adaptive radiation;
- African Great Lakes;
- aquatic locomotion;
- functional morphology;
Divergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species-rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.