Mammalian skeletal diversity

NSF DBI-2128146


Complex interactions among genetic, environmental, and phylogenetic mechanisms mediate and shape phenotypic diversity. Ongoing research efforts have largely followed disciplinary boundaries in micro- or macro-evolutionary scopes, genotypic or phenotypic data, and morphometric or biomechanic subdivisions of functional morphology. In this project, we will integrate genetic, biomechanical, ecological, and macroevolutionary approaches of morphological analysis and test hypotheses about the evolutionary drivers of mammalian skeletal diversity. We will first quantify heritability in skeletal traits by constructing a genetic covariance matrix that characterizes skeletal variation in a non-inbred pedigreed mouse population. We will then use the 55+ million year record of carnivoran mammals as our model system to (1) disentangle how genetic additive effects, biomechanics, developmental bias, and allometry influence skeletal diversity, (2) investigate ecomorphological convergence and its effects on evolutionary integration between skeletal systems, and (3) examine how paleoenvironmental changes influenced the tempo and mode of carnivoran skeletal diversity.

Law CJ, Hlusko LJ, & Tseng ZJ. 2024. Uncovering the mosaic evolution of the carnivoran skeletal system. Biology Letters. 20:20230526. doi.org/10.1098/rsbl.2023.0526

The carnivoran skeleton exhibits mosaic evolution, where only the mandible, hindlimb and posterior (i.e. last thoracic and lumbar) vertebrae showed evidence of adaptation towards ecological regimes. In contrast, the remaining skeletal components (i.e., cranium, forelimb, and anterior (cervical and thoracic) vertebrae exhibit clade-specific evolutionary shifts that corresponded well to carnivoran clades. We hypothesized that the decoupled evolution of individual skeletal components may have led to the origination of distinct adaptive zones and morphologies among extant carnivoran families that reflect phylogenetic hierarchies. 

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