Rodents show a wide range of anatomical, physiological, and behavioral adaptations to life underground. Cranial and postcranial bone morphologies are deeply impacted by the modes of digging, which can involve either incisors or claws. However, the morphological variation of these elements still needs to be accurately quantified to assess the degree of specializations of the fossorial rodent families in regards to their respective evolution. Here, we focus on the morpho-functional characteristics of the masticatory apparatus in two families of subterranean rodents, the Spalacidae and Bathyergidae. We quantify skull shape in five spalacid genera using geometric morphometric methods, as well as biomechanical estimates for adductor muscles, which are compared with data previously published on bathyergids. We show that skull shape of spalacids has a greater disparity and lower biomechanical estimates than bathyergids, in which the fossorial activity, notably chisel-tooth digging, more significantly impacted the evolution of the skull. Among spalacids, Spalax shows the most extreme specializations to life underground and displays the highest number of morphological convergences with chisel-tooth digging bathyergids, especially regarding its cranial shape and high biomechanical estimate for the temporalis muscle. Fewer morphological convergences were observed between other spalacids and bathyergids. Different evolutionary histories can potentially explain discrepancies observed between the two families, the first bathyergid morphological adaptations to fossorial life being much older than those of spalacids.

啮齿动物对地下生活表现出广泛的解剖，生理和行为适应性。颅骨和颅后骨的形态深受挖掘方式的影响，挖掘方式可能涉及门牙或爪子。然而，这些元素的形态变化仍然需要准确地量化，以评估各窝啮齿类动物的专业化程度。在这里，我们专注于地下啮齿动物的两个科，Spalacidae和Bathyergidae中咀嚼器的形态功能特征。我们使用几何形态计量学方法以及内收肌的生物力学估计来量化五个spalacid属的头骨形状，并将其与先前在bathyergids上发表的数据进行比较。我们显示，与邻苯二甲酸盐（stayyergids）相比，邻苯二甲酸的头骨形状具有更大的差异和更低的生物力学估计值，其中骨架活动（尤其是凿齿挖掘）对头骨的演化影响更大。在间苯二酸中，Spalax显示了最极端的地下生命专长，并且在凿齿挖掘的沉没动物身上表现出最多的形态学收敛，尤其是在颅骨形状和颞肌的高生物力学估计方面。其他spalacids和Bathyergids之间观察到较少的形态学收敛。不同的进化史可能解释了这两个家族之间的差异，第一个对峡湾生活的体温性形态学适应性早于邻苯二酸。