Imperfect morphological convergence: variable changes in cranial structures underlie transitions to durophagy in...

Area of Science:

• Evolutionary biology
• Comparative morphology
• Paleontology

Background:

• Convergence, the independent evolution of similar traits, highlights natural selection's role in shaping diversity.
• Understanding convergence requires examining factors like genetic background, environment, and the mapping of form to function.

Purpose of the Study:

• To investigate patterns of cranial morphology evolution following transitions to durophagy (hard-prey feeding) in moray eels.
• To assess the relative importance of natural selection, constraint, and contingency in driving evolutionary change.
• To determine if repeated evolution leads to predictable convergence or increased disparity.

Main Methods:

• Comparative analysis of cranial morphology across 15 durophagous moray eel species.
• Examination of 10 independent evolutionary transitions to durophagy within the Muraenidae family.
• Quantification of morphological disparity among durophagous species and their ancestors.

Main Results:

• Cranial morphology repeatedly evolved towards a state enhancing feeding performance on hard prey.
• Morphological disparity among durophagous species was greater than among ancestral species.
• Independent evolutionary transitions to durophagy involved lineage-specific suites of trait changes.

Conclusions:

• Evolutionary convergence is often imperfect, with lineages responding differently to similar selective pressures.
• Shared selective regimes, like durophagy, can promote diversification rather than uniform convergence.
• Lineage-specific responses to selection contribute to greater evolutionary disparity than predicted by simple convergence models.