Data from: Selective regimes and functional anatomy in the mustelid forelimb: diversification toward specializations for climbing, digging, and swimming

Anatomical traits associated with locomotion often exhibit specializations
for ecological niche, suggesting that locomotor specializations may
constitute selective regimes acting on limb skeletal traits. To test this,
I sampled 42 species of Mustelidae, encompassing climbing, digging, and
swimming specialists, and determined whether trait variation reflects
locomotor specialization by performing a principal components analysis on
14 forelimb traits. In addition to Brownian motion models, three
Ornstein–Uhlenbeck models of selective regimes were applied to PC scores
describing trait variation among mustelids: one without a priori defined
phenotypic optima, one with optima based upon locomotor habit, and one
with a single phenotypic optimum. PC1, which explained 43.8% of trait
variance, represented a trade-off in long bone gracility and deltoid ridge
length vs. long robustness and olecranon process length and distinguished
between climbing specialists and remaining mustelids. PC2, which explained
17.4% of trait variance, primarily distinguished the sea otter from other
mustelids. Best fitting trait diversification models are selective regimes
differentiating between scansorial and nonscansorial mustelids (PC1) and
selective regimes distinguishing the sea otter and steppe polecat from
remaining mustelids (PC2). Phylogenetic half-life values relative to
branch lengths suggest that, in spite of a strong rate of adaptation,
there is still the influence of past trait values. However, simulations of
likelihood ratios suggest that the best fitting models are not fully
adequate to explain morphological diversification within extant mustelids.