Patterns of phenotypic integration and modularity provide important clues to understand phenotypic evolution. Here, we investigate patterns of integration and modularity of the pelvic girdle in mammalian carnivorans. Three-dimensional geometric morphometrics was used to test for different modular hypotheses by combining in different ways the four original girdle elements (i.e., ilium, ischium, pubis, and acetabulum). These hypotheses were tested with the complete sample (i.e., order Carnivora) and within families. The hypotheses with more statistical support recognize the four girdle elements as separate modules, with the ischium and pubis more integrated than the ilium and acetabulum. This indicates a strong influence of developmental units in shaping pelvic anatomy. Strikingly, the families Canidae and Ursidae exhibit a different pattern of modularity, showing a modification of the pattern displayed by the whole order, which was attained early in the evolution of the group. Our results indicate that, on long timescales, evolution can change the relationships between structures independently of the developmental patterning, thus overcoming evolutionary constraints.

中文翻译：

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改变食肉动物骨盆带的模块化模式

表型整合和模块化的模式为理解表型进化提供了重要线索。在这里，我们研究了哺乳动物食肉动物骨盆带的整合和模块化模式。通过以不同方式组合四种原始腰带元素（即髂骨、坐骨、耻骨和髋臼），使用三维几何形态计量学来测试不同的模块化假设。这些假设在完整样本（即食肉目）和家庭内部进行了测试。有更多统计支持的假设将四个腰带元素视为独立的模块，坐骨和耻骨比髂骨和髋臼更完整。这表明发育单位在塑造骨盆解剖结构方面有很强的影响。引人注目的是，Canidae 和 Ursidae 科表现出不同的模块化模式，显示出整个目所显示的模式的修改，这是在该组的早期进化中实现的。我们的结果表明，在很长的时间尺度上，进化可以独立于发展模式改变结构之间的关系，从而克服进化限制。