Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles
Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles
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DOI：
10.1046/j.1439-0264.2002.00396.x
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发表时间：
2002-08-01
期刊：
影响因子：
--
通讯作者：
Hayashi, Y
中科院分区：
文献类型：
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作者：
Endo, H;Aoki, R;Hayashi, Y
通过对印度长鼻鳄（Gavialis gangeticus）、假长鼻鳄（Tomistoma schlegelii）和非洲长鼻鳄（Mecistops cataphractus）颅骨咀嚼肌及其相关结构的观察，详细阐述了与其他鳄鱼种类的形态学差异，并对这些长鼻鳄咀嚼器的功能策略进行了比较和阐明。与许多短鼻鳄相比，这三种鳄鱼的后翼状肌相对较小。说明食鱼类长吻鳄的咀嚼力不如短吻鳄，而三种长吻鳄的咀嚼肌在形态上存在以下差异。假尿道后翼状突在下颌外侧延伸，与印度尿道不同。假颞肌和颞上肌主要发育于印度牛颈肌，但我们认为其他两个物种在该肌肉中具有弱束。假鳄和非洲细鼻鳄的翼状骨发育良好，向背腹侧延伸，表明与翼状骨相连的下颌后收肌可能比印度鳄的大得多。这些数据从形态学上阐明了长鼻鳄鱼与短鼻鳄鱼咀嚼机制的不同，并证明了印度鳄与其他两个物种之间在咀嚼肌肉中共享功能作用的进化策略是不同的。我们还获得了马其坎鳄鱼（Toyotamaphymeia machickanense）化石颅骨的形态资料，并从化石特征中得出结论，该物种的M.pterygoideus posterior和m.p ytemporalis的相当大的发育在形态上与印度和假鳄鱼都不一致。
The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus ), the false gavial (Tomistoma schlegelii ), and the African slender-snouted crocodile (Mecistops cataphractus ) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense ) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been consistent with both the Indian and false gavials.