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首页> 外文期刊>Geodiversitas >Structural, functional, and physiological signals in ichthyosaur vertebral centrum microanatomy and histology
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Structural, functional, and physiological signals in ichthyosaur vertebral centrum microanatomy and histology

机译：鱼龙脊椎中枢显微解剖和组织学中的结构，功能和生理信号

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摘要

The first tuna-shaped amniotes evolved among ichthyosaurs, but this group exhibits in fact a wide diversity of morphologies and swimming modes. The histology and microanatomical features of vertebral centra of a diversity of ichthyosaur taxa from most basal to highly derived illustrating this variability were analyzed. The occurrence of unusual parallel fibered bone with platings of true parallel-fibered bone confirms high growth rate in all these taxa. Ichthyosaur vertebrae, which are deeply amphicoelous, show a limited endosteal territory associated with a limited growth in length. No bone mass increase nor decrease occurs. The vertebral centrum is spongious, and two microtypes are observed in the periosteal territory, with different degrees of organization of the trabecular network. The microtypes appear to be associated with the shape of the vertebral centrum, the organization of the spongiosa becoming homogeneous in the disk-shaped centra of cymbospondylids and Neoichthyosauria, rather than much more heterogeneous in spool-shaped centra of primitive Triassic forms. As opposed to what was previously suggested in other amniotes, the main switch in microanatomical organization appears thus to be correlated to the acquisition of deeply amphicoelous disk-like vertebral centra rather than to a shift in swimming mode from long and slender-bodied anguilliform swimmers to thunniform swimmers.
机译：第一种金枪鱼形状的羊膜在鱼龙中进化，但实际上这组鱼展现出各种各样的形态和游泳方式。从最基础到高度衍生的鱼龙类生物分类的椎体中枢的组织学和显微解剖特征进行了分析，说明了这种变化。真正的平行纤维骨镀层中异常平行纤维骨的出现证实了所有这些类群的高生长速率。鱼鳞龙的椎骨是深两栖的，显示出有限的骨内膜区域和长度的增长。没有骨量增加或减少。椎体中央呈海绵状，在骨膜区域观察到两种微型，其小梁网络的组织程度不同。微型型似乎与椎体中枢的形状有关，海绵体的组织在枕形小体和新鱼胸尿的盘状中部变得均匀，而不是在原始三叠纪形式的线轴状中部更加不均匀。与以前其他羊膜动物所建议的相反，微观解剖学组织的主要转变似乎与深部两栖盘状椎体的获得有关，而不是与游泳模式从长而纤细的无角形游泳者转变为游泳者有关。丁字形游泳者。

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