Data from: Sexual selection on skeletal shape in Carnivora

Lifetime reproductive success of males is often dependent upon the ability to physically compete for mates. However, species variation in social structure leads to differences in the relative importance of intraspecific aggression. Here we present a large comparative data set on sexual dimorphism in skeletal shape in Carnivora to test the hypotheses that carnivorans exhibit sexual dimorphism in skeletal anatomy that is reflective of greater specialization for physical aggression in males relative to females and that this dimorphism is associated with the intensity of sexual selection. We tested these hypotheses using a set of functional indices predicted to improve aggressive performance. Our results indicate that skeletal shape dimorphism is widespread within our sample. Functional traits thought to enhance aggressive performance are more pronounced in males. Phylogenetic model selection suggests that the evolution of this dimorphism is driven by sexual selection, with the best-fitting model indicating greater dimorphism in polygynous versus non-polygynous species. Skeletal shape dimorphism is correlated with body size dimorphism, a common indicator of the intensity of male-male competition, but not with mean body size. These results represent the first evidence of sexual dimorphism in the primary locomotor system of a large sample of mammals.雄性的终生繁殖成功率通常取决于其通过身体竞争获取配偶的能力。然而不同物种的社会结构存在差异，导致种内攻击性（intraspecific aggression）的相对重要性各不相同。本研究构建了一套针对食肉目（Carnivora）骨骼形态性二态性（sexual dimorphism）的大型比较数据集，用以验证两项假说：其一，食肉目动物的骨骼解剖结构存在性二态性，且该特征反映出雄性相较于雌性更特化于身体对抗行为；其二，这类性二态性与性选择（sexual selection）强度相关联。本研究采用一组被认为可提升对抗表现的功能指标对上述假说进行了验证。研究结果显示，骨骼形态性二态性在本次采样样本中广泛存在，且被认为可强化对抗能力的功能性状在雄性个体中表现得更为显著。系统发育模型（phylogenetic model）选择结果表明，这类性二态性的演化由性选择驱动；最优拟合模型显示，一雄多雌制（polygynous）物种的性二态性程度高于非一雄多雌制物种。骨骼形态性二态性与体型性二态性存在关联——后者是衡量雄性间竞争强度的常用指标，但与平均体型并无相关性。本研究结果首次为大型哺乳动物样本的主要运动系统存在性二态性提供了实证依据。