Testing for heterogeneous rates of discrete character evolution on phylogenies

Area of Science:

• Phylogenetic comparative biology
• Macroevolutionary and microevolutionary processes
• Evolutionary biology

Background:

• Hypotheses in phylogenetic comparative biology often focus on changes in trait evolution rates.
• Connecting macroevolutionary patterns to microevolutionary processes requires methods to detect rate shifts.

Purpose of the Study:

• To present a novel statistical method for testing rate shifts in discrete character evolution.
• To apply this method to Anolis lizard trait evolution (dewlap color, caudal vertebrae).
• To evaluate the statistical properties of the new method.

Main Methods:

• A new method to test for changes in the rate of discrete character evolution.
• User-specified 'regimes' for evolutionary rate changes, unlike data-inferred methods.
• Application to Anolis lizards, comparing Caribbean and mainland clades.

Main Results:

• Little evidence for differences in evolutionary processes between mainland and island Anolis clades for the studied traits.
• The method demonstrates acceptable statistical properties, including type I error, parameter estimation, and statistical power.
• The study contributes to understanding heterogeneity in discrete character evolution rates on phylogenies.

Conclusions:

• The developed method provides a robust tool for hypothesis testing in evolutionary biology.
• No significant evolutionary rate differences were detected between island and mainland Anolis populations for dewlap color or caudal vertebrae number.
• The findings contribute to discussions on frequentist hypothesis testing and model adequacy in evolutionary studies.