Trait-specific processes of convergence and conservatism shape ecomorphological evolution in ground-dwelling...

Area of Science:

• Evolutionary Biology
• Ecomorphology
• Phylogenetics

Background:

• Understanding phenotypic diversity relies on linking traits to evolutionary processes.
• Distinct evolutionary processes can produce similar phenotypic patterns, complicating driver identification.
• Ground squirrel radiation offers a model to study convergence and constraint impacting phenotypic diversity.

Purpose of the Study:

• To investigate ecomorphological evolution in ground squirrels.
• To differentiate the roles of convergence and constraint in shaping phenotypic diversity.
• To assess macroevolutionary dynamics using multiple trait datasets within a phylogenetic framework.

Main Methods:

• Utilized four ecologically relevant trait datasets: body size, cranial, mandibular, and molariform tooth shape.
• Analyzed variation, covariation, and disparity patterns within a new phylogenetic framework.
• Employed phylogenetic comparative methods to infer evolutionary modes and regimes.

Main Results:

• Identified strong correlations between body size and skull traits (allometry) and among skull traits (integration).
• Inferred concordant evolutionary modes across traits, suggesting similar adaptive regimes.
• Revealed divergent macroevolutionary dynamics, with phenotypic disparity shaped differently by convergence and conservatism across traits.

Conclusions:

• Ground squirrel evolution is characterized by mosaic patterns, with heterogeneity in evolutionary processes across traits.
• Macroevolutionary inference can be biased by relying on single traits; broader trait-bases are crucial.
• Convergence and conservatism differentially impact phenotypic disparity, highlighting the complexity of evolutionary drivers.