Biomechanical Specialization Acts as an Asymmetrical Constraint on the Phenotype

Area of Science:

• Evolutionary Biology
• Comparative Anatomy
• Functional Morphology

Background:

• Vertebrate jaw evolution is shaped by trade-offs between velocity and force transmission.
• These trade-offs influence feeding performance and anatomical complexity.

Purpose of the Study:

• Investigate the velocity-force trade-off in 89 percid fish species.
• Test hypotheses on symmetrical vs. asymmetrical constraints on jaw diversity.
• Explore implications for craniofacial adaptation and macroevolutionary patterns.

Main Methods:

• Comparative analysis of jaw morphology across 89 percid fish species.
• Quantification of craniofacial diversity and phenotypic evolution rates.
• Testing hypotheses on the impact of velocity-force trade-offs.

Main Results:

• The velocity-force trade-off significantly constrains jaw structural diversity.
• Force-modified jaws are compact; velocity-modified jaws are robust with elongate snouts.
• Phenotypic diversity and evolutionary rates are asymmetrically distributed between jaw types.

Conclusions:

• Jaw specialization acts as a phenotypic constraint, leading to asymmetrical macroevolutionary patterns.
• Asymmetrical evolutionary rates and diversity distribution may explain uneven vertebrate diversity.
• Trade-offs are a crucial, underappreciated driver of macroevolutionary patterns.