Many studies have attested to the consequences of the recent and intense artificial selection on the morphological variability of the cranium and mandible in domestic animals. However, the functional relations of the cranium with other constituents of the masticatory apparatus (the mandibles and the adductor muscles) have rarely been explored. Previous work has demonstrated strong relationships between the overall shape of the mandible and muscle data, however, drastic artificial selection in dogs has led to frequent malocclusions, suggesting a possible decoupling between the cranium and the mandible. Moreover, the more complex role of the cranium suggests that it is likely less impacted by, and correlated with, the architecture of the jaw muscles than the mandible. We explored the covariations between cranial and mandibular shape and between cranial shape and the masticatory muscle architecture. Shape analyses were conducted on 58 dogs from various breeds and we used muscle data previously obtained from the dissection of 48 of these dogs. The shape of the cranium was quantified using 3D geometric morphometric approaches. Principal component analyses (PCA) and two-block partial least square analyses (2B-PLS) were used to quantify the variations in cranial shape and the covariations with mandible shape and muscle architecture, respectively. Interestingly, our results reveal strong covariations between cranial shape and mandibular shape and between cranial shape and masticatory muscles mass or physiological cross-sectional area, irrespective of whether size is taken into account or not. We conclude that the drastic artificial selection in domestic dogs has not tainted the integrity of the jaw system, which reinforces previous assumptions hypothesising that phenotypic variability in dogs may be limited by developmental factors.

许多研究证明，最近进行的大量人工选择对家畜的颅骨和下颌骨的形态变异具有影响。但是，很少研究颅骨与咀嚼装置的其他组成部分（下颌骨和内收肌）的功能关系。先前的工作证明了下颌骨的整体形状与肌肉数据之间的密切关系，但是，狗的剧烈人工选择导致了经常出现错牙合，这表明颅骨和下颌骨之间可能存在脱钩。此外，颅骨的作用更为复杂，表明其受下颌肌肉结构的影响较小，而与下颌骨的结构相关的可能性较小。我们探索了颅骨和下颌形状之间以及颅骨形状和咀嚼肌结构之间的协变。对来自不同品种的58只狗进行了形状分析，我们使用了以前从这些狗中的48只解剖获得的肌肉数据。颅骨的形状使用3D几何形态计量学方法进行了量化。主成分分析（PCA）和两块偏最小二乘分析（2B-PLS）分别用于量化颅骨形状的变化以及下颌骨形状和肌肉结构的协变。有趣的是，我们的研究结果表明，无论是否考虑大小，颅骨形状与下颌骨形状之间以及颅骨形状与咀嚼肌质量或生理学横截面积之间都存在很强的协变关系。