Mandibular growth and function in Archaeolemur.
Mandibular growth and function in Archaeolemur.
复制标题
古鼠下颌的生长和功能。
DOI：
10.1002/ajpa.1330950106
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发表时间：
1994
影响因子：
2.8
通讯作者：
Simons,EL
中科院分区：
文献类型：
--
作者：
Ravosa,MJ;Simons,EL
在《古狐猴》中描述了下颌联合形态的个体发育变化，以推测在这个马达加斯加狐猴亚化石中联合融合的功能意义。关节联合最先表现出较复杂形态的区域是关节的下缘和前缘，其次是上横环和下横环的舌缘。在生长过程中，这些区域变得越来越皱纹，侵占了位于中心的光滑的椭圆形区域，这可能是神经血管结构与未融合关节沟通的主要途径。在亚成人中，联合完全融合，除了下横环的舌面，在那里有一条公开的缝线和潜在的间隙存在于牙齿之间。因此，在古龙中，存在与年龄和大小相关的联合骨化或融合增加的模式，并在成年时完成。互锁骨突的形态和联合中的骨化序列表明，咀嚼过程中背腹侧剪应力的增加是最有可能的联合融合的决定因素：更大的联合融合的异速生长模式可能与成人存在相对较大的背腹侧剪切有关，这是由于平衡侧颌骨-肌肉力量的增加。几乎没有迹象表明，幼年古埃及人的联合被支撑起来，以抵抗咀嚼过程中的“愿望骨”或切开过程中的垂直弯曲相关的力。我们和其他人的观察结果表明，灵长类动物的联合融合最初是对咀嚼过程中背腹剪切增加的一种反应。因此，在那些形成融合的联合以对抗背腹剪切增加的分类群中，意愿骨应力可能只成为联合的形式和功能的主要决定因素。©1994 Wiley-Liss，Inc.
Ontogenetic changes in the morphology of the mandibular symphysis are described inArchaeolemurso as to infer the functional significance of symphyseal fusion in this subfossil Malagasy lemur. The first regions of the symphysis to show a more complex morphology were the lower and anterior borders of the joint and, to a lesser extent, the lingual borders of the superior and inferior transverse tori. During growth, these regions became increasingly rugose and encroached upon a centrally located, smooth, “oval” region, which may have been a principal pathway for neurovascular structures communicating with the unfused joint. In subadults, the symphysis was completely fused except for the lingual surface of the inferior transverse torus, where a patent suture and potential space were present between dentaries. Thus, inArchaeolemurthere was an age‐ and size‐related pattern of increased symphyseal ossification or fusion that was complete by adulthood.The morphology of the interlocking bony processes and the sequence of ossification in the symphysis suggest that increased dorsoventral shear stress during mastication was the most likely determinant of symphyseal fusion inArchaeolemur: The allometric pattern of greater symphyseal fusion may be linked to the presence of relatively greater dorsoventral shear in adults due to an increased recruitment of balancing‐side jaw‐muscle force. There is little indication that the symphysis of juvenileArchaeolemurwas buttressed to resist forces associated with “wishboning” during mastication or vertical bending during incision. Our observations, as well as those of others, suggest that symphyseal fusion in primates occurs initially as a response to increased dorsoventral shear during mastication. Therefore, wishboning stress might only become a major determinant of symphyseal form and function in those taxa that develop a fused symphysis to counter increased dorsoventral shear. © 1994 Wiley‐Liss, Inc.