We estimated the divergence times of major cichlid lineages as part
of the longer evolutionary history of teleostean fishes. Our results
and those of a recent molecular study based on both mitochondrial and
nuclear data sets [7] support a vicariant history of cichlid divergences, while other researchers [19]
have argued for the dispersal hypothesis. We presented additional
strong evidence for the vicariant hypothesis and propose that the
vicariant assumption can be used to generate time constraints to date
other teleostean divergences in both deeper (100–300 MYA) and shallower
(< 100 MYA) time ranges.
This could be a significant contribution toward the reliable dating
of teleostean divergence times in light of the scarcity of teleostean
fossil records in the Mesozoic and later (see above) and the probable
deviation of molecular evolutionary rates of fishes from those of
tetrapods [5,62],
for which molecular evolutionary rates are more reliably studied using
ampler fossil records. A further exploration of biogeography-based time
constraints for other groups of freshwater fishes that could be
reasonably incorporated into the dating study (e.g. rainbowfishes [63]) would be expected to increase the accuracy and precision of teleostean divergence time estimates.
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