Spectral peak absorbance for the Lake Malawi cichlids follows a heterochronic shift compared with that of the river-dwelling tilapia, as inferred from opsin gene expression. Tilapia opsins shift in their peak absorbance from lower to higher wavelengths during development. Rock-dwelling clades, such as Metriaclima zebra, M. zebra 'gold' (another member of the Metriaclima species complex), Labeotropheus fuelleborni and Metriaclima benetos, show a neotenic pattern, in which peak wavelengths increase during development but at a slower rate than in tilapia. Sand-dwelling clades, such as Dimidiochromis compressiceps and Tramitichromis intermedus, undergo direct development, with the peak wavelengths high right through development. Adapted from Carleton et al. .
Jones et al. Journal of Biology 2008 7:26 doi:10.1186/jbiol86