Performance Surface Analysis Identifies Consistent Functional Patterns across 10 Morphologically Divergent...

Area of Science:

• Evolutionary biology
• Functional morphology
• Paleontology

Background:

• Performance surfaces offer new ways to study adaptive landscapes and evolutionary diversification.
• Turtle shells are ideal models for evolutionary functional analysis due to their distinct functions.

Purpose of the Study:

• To test if turtle lineages transitioning to terrestrial habitats exhibit shell shape evolution linked to decreased hydrodynamic performance.
• To evaluate the efficacy of performance surface methods in analyzing complex evolutionary patterns.

Main Methods:

• Utilized performance surfaces analyzing three turtle shell functions: strength, hydrodynamics, and self-righting.
• Examined shell shape evolution in ten turtle lineages transitioning from aquatic to terrestrial environments.

Main Results:

• Most terrestrial turtle lineages showed morphological changes consistent with reduced hydrodynamic performance.
• This pattern held true even in lineages with increased shell height, contrary to simple assumptions.
• Divergent shell shapes in terrestrial turtles were associated with a common selective shift away from hydrodynamics.

Conclusions:

• The transition to terrestrial habitats commonly leads to a decreased selective importance of shell hydrodynamics in turtles.
• Performance surface analyses effectively reveal functional implications of macroevolutionary changes.
• These methods can integrate adaptive and performance data in macroevolutionary studies.