An outcome of Hans Recknagel's Leonardo da Vinci pre-PhD research training stint with Kathryn Elmer in Glasgow, an elegant little paper on Midas cichlids and their environment:
CRATER LAKE HABITAT PREDICTS MORPHOLOGICAL DIVERSITY IN ADAPTIVE RADIATIONS OF CICHLID FISHES
We found that lakes with a larger littoral zone had Midas cichlids with, on average, a higher (i.e. more "benthics") body shape. We also found that the variability in body elongation (i.e. how much morphological spread the flock has across the benthic-limnetic axis) is significantly predicted by average lake depth. Overall, this suggests that part of the reason for the unequal distribution of species across the crater lakes might be that there is insufficient ecological opportunity in some of the small or very steep crater lakes.