Cranial sutures connect adjacent bones of the skull and play an important role in the absorption of stresses that may occur during different activities. The Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis has been extensively studied over the years in terms of skull biomechanics, but without a detailed description of the function of cranial sutures. In the present study, 34 thin sections of cranial sutures were examined in order to determine their histovariability and interpret their biomechanical role in the skull. The histological model was compared with three‐dimensional‐finite element analysis (FEA) simulations of the skull under bilateral and lateral biting as well as skull‐raising loads for maximum and minimum principal stress. Histologically, only two sutural morphologies were recognised in the skull of Metoposaurus: interdigitated sutures (commonly associated with compressive stresses) are dominant along the entire length of the skull roof and palate; tongue‐and‐groove sutures (commonly associated with tensile stresses) are present across the maxilla. FEA shows a much more complex picture of stress type and distribution than predicted by sutures. Common to both methods is a predominance of compressive stresses which act on the skull during biting. The methods predict different stress regimes during biting in the posterior part of the skull: where histological analysis suggests compression, FEA predicts tension. For lateral biting and skull raising, histological and digital reconstructions show similar general patterns but with some variations.

中文翻译：

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波兰上三叠统克拉西约氏甲龙（Temnospondyli，Stereospondyli）的颅缝生物力学

颅缝线连接颅骨的相邻骨骼，在吸收不同活动期间可能发生的压力方面发挥重要作用。多年来，在颅骨生物力学方面对晚三叠世 temnospondyl 两栖动物 Metoposaurus krasiejowensis 进行了广泛研究，但没有详细描述颅骨缝合线的功能。在本研究中，检查了 34 个颅缝的薄切片，以确定它们的组织变异性并解释它们在颅骨中的生物力学作用。将组织学模型与颅骨在双侧和侧向咬合以及颅骨抬高载荷下最大和最小主应力的三维有限元分析 (FEA) 模拟进行比较。在组织学上，在甲龙的头骨中仅识别出两种缝合形态：指状缝合线（通常与压缩应力相关）在颅顶和上颚的整个长度上占主导地位；舌槽缝线（通常与拉伸应力相关）存在于上颌骨上。FEA 显示的应力类型和分布图比缝合线预测的要复杂得多。这两种方法的共同点是在咬合过程中作用在头骨上的压应力占优势。这些方法预测在颅骨后部咬合期间的不同应力状态：组织学分析表明压缩，FEA 预测张力。对于侧咬和颅骨抬高，组织学和数字重建显示出类似的一般模式，但有一些变化。