Testing hypotheses of convergence with multivariate data: morphological and functional convergence among herbivorous...

Area of Science:

• Evolutionary biology
• Comparative anatomy
• Quantitative paleontology

Background:

• Convergence, a key evolutionary concept, is often understudied and qualitatively assessed.
• Quantitative frameworks for studying evolutionary convergence are needed.

Purpose of the Study:

• To develop and apply quantitative methods to study evolutionary convergence in lizard skulls and jaws.
• To investigate convergence patterns in herbivorous lizards across morphological and functional systems.
• To test hypotheses regarding the morphospace patterns and functional drivers of convergence.

Main Methods:

• Digitized coordinate data from 1554 lizard skulls and 1292 lower jaws.
• Relative warp analysis and permutation tests to identify and validate convergent patterns.
• Phylogenetic comparative methods to contextualize morphological and functional shifts.

Main Results:

• Herbivorous lizards exhibit convergence in skull morphology, deviating towards a common morphospace area.
• Lower jaws of herbivores do not show morphological convergence but do show functional convergence towards higher mechanical advantage.
• Phylogenetic perspective is crucial for recognizing convergence patterns.

Conclusions:

• Quantitative, phylogenetically informed methods are essential for robustly studying evolutionary convergence.
• Morphological and functional convergence can occur independently, even within the same organismal system.
• Herbivory in lizards drives distinct evolutionary trajectories in skull and jaw morphology and function.