Cranial suture complexity in caviomorph rodents (Rodentia; Ctenohystrica)
Cranial suture complexity in caviomorph rodents (Rodentia; Ctenohystrica)
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DOI：
10.1002/jmor.20699
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发表时间：
2017-08-01
影响因子：
1.5
通讯作者：
Vassallo, Aldo
中科院分区：
文献类型：
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作者：
Buezas, Guido;Becerra, Federico;Vassallo, Aldo
由于其灵活性，缝合线是比周围刚性颅骨承受更大应变的区域。颅骨缝合线的交叉程度或复杂性各不相同。有证据表明，更复杂的缝合线能够更好地吸收来自动态咀嚼力和其他功能的高应力。啮齿动物目是一个有趣的研究分支，因为它的分类群具有不同的咀嚼模式。由于啃咬和研磨造成的反复负荷，缝线吸收能量可能是这些哺乳动物的一个关键因素。由于其生态形态和饮食多样性，Caviomorpha 下目物种被选为案例研究。这项研究比较了来自七个 caviomorph 家族的讲台和颅顶的 5 条缝合线，并通过相对长度和分形维数评估了它们的复杂性。在这些啮齿类动物中，颅缝在形态上非常多样化。我们发现连接讲台和穹窿的缝线比颅顶本身的缝线交指程度更高，尤其是前颌前额缝线。在表现出凿齿挖掘和挖洞行为的物种中，特别是在 Ctenomyidae 和 Octodontidae 中，缝合线交指比在 Dasyproctidae 和 Cuniculidae 中的物种更高，后者具有更纤细的咀嚼系统。在科和物种系统发育上对祖先特征状态的重建表明，低缝合线指叉（即低长度比）是额间、前颌前额和颌前额缝合线的可能祖先状态。这里显示的缝线形态的种间差异可能代表了对不同机械需求（即软食物与硬食物）或行为（例如凿齿挖掘）的适应，这些适应与豚鼠啮齿类动物所处的不同环境密切相关。
Due to their flexibility, sutures are regions that experience greater strains than the surrounding rigid cranial bones. Cranial sutures differ in their degree of interdigitation or complexity. There is evidence indicating that a more convoluted suture better enables the absorption of high stresses coming from dynamic masticatory forces, and other functions. The Order Rodentia is an interesting clade to study this because of its taxa with diverse chewing modes. Due to repeated loading resulting from gnawing and grinding, energy absorption by the sutures might be a crucial factor in these mammals. Species within the infraorder Caviomorpha were chosen as a case study because of their ecomorphological and dietary diversity. This study compared five sutures from the rostrum and cranial vault across seven caviomorph families, and assessed their complexity by means of the relative length and fractal dimension. Across these rodents, cranial sutures are morphologically quite diverse. We found that the sutures connecting the rostrum with the vault were relatively more interdigitated than those in the cranial vault itself, especially premaxillofrontal sutures. Suture interdigitation was higher in species that display chisel-tooth digging and burrowing behaviors, especially in the families Ctenomyidae and Octodontidae, than those in families Dasyproctidae and Cuniculidae, which have more gracile masticatory systems. The reconstruction of the ancestral character state, on family and species phylogeny, points toward low suture interdigitation (i.e., low length ratio) as a likely ancestral state for interfrontal, premaxillofrontal and maxillofrontal sutures. Interspecific differences in suture morphology shown here might represent adaptations to different mechanical demands (i.e., soft vs. tough foods) or behaviors (e.g., chisel-tooth digging), which evolved in close association with the diverse environments occupied by caviomorph rodents.