Testing hypotheses of skull function with comparative finite element analysis: three methods reveal contrasting...

Area of Science:

• Biomechanics
• Comparative Anatomy
• Finite Element Analysis

Background:

• Comparative finite element analysis (FEA) often standardizes models for cross-species loading scenarios.
• Defining 'equivalent' loading in vertebrate feeding biomechanics is hypothesis-dependent.

Purpose of the Study:

• To demonstrate how different muscle force scaling methods in FEA of marsupial skulls (Potoroidae) can lead to opposing comparisons of stress and strain.
• To propose three distinct hypothesis-driven muscle scaling categories for analyzing skull biting mechanics.

Main Methods:

• Comparative finite element analysis of 13 diverse marsupial bettong and potoroo skulls.
• Muscle force scaling was standardized using three distinct approaches tailored to specific hypotheses.

Main Results:

• Standardizing muscle forces to analyze skull biting mechanics can produce opposing comparisons of stress or strain.
• The choice of muscle scaling method significantly impacts the interpretation of FEA results for feeding biomechanics.

Conclusions:

• Three categories of hypotheses for skull biting mechanics are proposed, each requiring a unique muscle scaling method: (1) input muscle force to skull size for force distribution efficiency, (2) mechanical advantage for size-adjusted equivalent bites, and (3) bite reaction force for feeding ecology and niche partitioning.