Strain in the galago facial skull.
Strain in the galago facial skull.
复制标题
加拉戈面部头骨的应变。
DOI：
10.1002/1097-4687(200007)245:1
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Hylander,WL
中科院分区：
文献类型：
--
作者：
Ravosa,MJ;Johnson,KR;Hylander,WL
很少有实验工作是针对了解应力分布沿着面颅骨在日常咀嚼行为。这些信息对于理解哺乳动物眶周区的功能意义是重要的。在这项研究中，骨应变记录沿着背眶间，眶后杆，下颌体在耳，石榴石和O. crassicaudatus（大galagos）在磨牙咀嚼和咬合。我们确定了主应变的大小和方向，比较了不同区域的峰值剪应变大小，并将galago应变模式与类似的实验数据进行了比较。这套分析用于测试面部扭转模型（Greaves [1985] J Zool（Lond）207：125 - 136;[1991] Zool J Linn Soc 101：121 - 129;[1995] Functional morphology in vertebrate paleontology.剑桥：剑桥大学出版社，第99 - 115页）。在强有力的咀嚼过程中的盔环眶和下颌骨峰值应变的比较表明，环眶应变的幅度非常低。这表明，在类人猿中，链鼻环眶区域高度过度构建，以对抗常规咀嚼负荷。事实上，在两个灵长目亚目中，眶周峰值应变幅度都很低，这破坏了任何强调咀嚼应力作为眶周形态、功能和进化决定因素的重要性的模型。初步数据还表明，在体型较大的灵长类动物中，下颌和眶周应变之间的差异更大。这种模式被解释为意味着眶周区域必须存在足够的皮质骨，以防止由于非咀嚼创伤力而导致的结构失效。单侧咀嚼时，眶间额突背侧的X线1方向提示面扭转和额面弯曲的存在。咀嚼时的眶后杆主应变方向平均相对于颅骨长轴非常接近45 °，与面部扭转模型预测的非常一致。当咀嚼从面部的一侧转移到另一侧时，眶间杆和眶后杆的主应变方向都有特征性的反转或翻转。虽然类星体也表现出轨道间的反转模式，但这个分支的峰值应变方向与星系相反。这种变化的存在可能是由于相对平衡侧颌肌肉力量恢复的亚目差异。最重要的是，尽管Galago眶周区域的应变方向数据为面部扭转的发生提供了支持，但这些应变的低幅度表明这种载荷模式可能不是眶周形态的重要决定因素。J. Morphol. 245：51 - 66，2000 © 2000 Wiley利斯公司
Little experimental work has been directed at understanding the distribution of stresses along the facial skull during routine masticatory behaviors. Such information is important for understanding the functional significance of the mammalian circumorbital region. In this study, bone strain was recorded along the dorsal interorbit, postorbital bar, and mandibular corpus inOtolemur garnettiiandO.crassicaudatus(greater galagos) during molar chewing and biting. We determined principal‐strain magnitudes and directions, compared peak shear‐strain magnitudes between various regions of the face, and compared galago strain patterns with similar experimental data for anthropoids. This suite of analyses were used to test the facial torsion model (Greaves [1985] J Zool (Lond) 207:125–136; [1991] Zool J Linn Soc 101:121–129; [1995] Functional morphology in vertebrate paleontology. Cambridge: Cambridge University Press, p 99–115). A comparison of galago circumorbital and mandibular peak strains during powerful mastication indicates that circumorbital strains are very low in magnitude. This demonstrates that, as in anthropoids, the strepsirhine circumorbital region is highly overbuilt for countering routine masticatory loads. The fact that circumorbital peak‐strain magnitudes are uniformly low in both primate suborders undermines any model that emphasizes the importance of masticatory stresses as a determinant of circumorbital form, function, and evolution. Preliminary data also suggest that the difference between mandibular and circumorbital strains is greater in larger‐bodied primates. This pattern is interpreted to mean that sufficient cortical bone must exist in the circumorbital region to prevent structural failure due to nonmasticatory traumatic forces. During unilateral mastication, the direction of ϵ1at the galago dorsal interorbit indicates the presence of facial torsion combined with bending in the frontal plane. Postorbital bar principal‐strain directions during mastication are oriented, on average, very close to 45° relative to the skull's long axis, much as predicted by the facial torsion model. When chewing shifts from one side of the face to the other, there is a characteristic reversal or flip‐flop in principal‐strain directions for both the interorbit and postorbital bar. Although anthropoids also exhibit an interorbital reversal pattern, peak‐strain directions for this clade are opposite those for galagos. The presence of such variation may be due to suborder differences in relative balancing‐side jaw‐muscle force recruitment. Most importantly, although the strain‐direction data for the galago circumorbital region offer support for the occurrence of facial torsion, the low magnitude of these strains suggests that this loading pattern may not be an important determinant of circumorbital morphology. J. Morphol. 245:51–66, 2000 © 2000 Wiley‐Liss, Inc.