Performance in three shell functions predicts the phenotypic distribution of hard-shelled turtles

Area of Science:

• Evolutionary biology
• Paleontology
• Biomechanics

Background:

• Adaptive landscapes are crucial for understanding evolution, with traditional methods relying on evolutionary modeling.
• Recent approaches explore links between phenotype, functional performance, and adaptive landscapes.

Purpose of the Study:

• To develop and validate a performance surface-based method for inferring adaptive landscapes.
• To explain species distribution and diversification patterns using functional performance data.

Main Methods:

• Collected performance data for turtle shell functions: strength, hydrodynamic efficiency, and self-righting.
• Developed predicted performance optima in shell shape space.
• Compared performance surface-based inferences with traditional modeling approaches.

Main Results:

• Performance optima distribution closely matched existing turtle species distribution.
• The method explained species absences in underrepresented morphospace regions.
• Performance-based method outperformed modeling in identifying adaptive peaks and explaining phenotypic distributions.

Conclusions:

• Functional performance directly influences macroevolutionary diversification.
• Performance surface-based methods offer a more direct link between function and species distribution.
• This approach enhances understanding of evolutionary trajectories and species diversification.