Elasmobranch Central Nervous System Organization and Its Possible Evolutionary Significance
Elasmobranch Central Nervous System Organization and Its Possible Evolutionary Significance
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软骨鱼中枢神经系统组织及其可能的进化意义
DOI：
10.1093/icb/17.2.411
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发表时间：
1977
影响因子：
2.6
通讯作者：
R. Northcutt
中科院分区：
文献类型：
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作者：
R. Northcutt
对鲨鱼脑与身体比例的研究表明，这些分类群的相对脑容量与硬骨鱼、鸟类和哺乳动物的脑容量重叠。大部分的变异是由于端脑和小脑的相对发育。端脑重量从角鲨的24%到Sphyrna的52%不等。对鲨鱼大脑细胞结构的分析揭示了至少两种发育模式。角鲨具有低的脑：身体比例，这些分类群的端脑具有发达的侧脑室和不发达的苍白区域。间脑的特点是突出的室周板，小脑缺乏叶。板状鲨和真鲨的特点是脑体比高，端脑明显肥大。顶盖（苍白球）区域以及间脑的特点是广泛的细胞迁移。这些类型的小脑具有广泛的复杂的叶状结构。
这些大脑模式与Holocephali的大脑组织进行比较，我得出结论，Holocephalans是一个姐妹辐射的板鳃类。与硬骨鱼和陆地脊椎动物的比较表明，板鳃类有独立发展的复杂的苍白球领域和小脑叶状平行的进化趋势的结果。
Examination of shark brain:body ratios reveals that these taxa possess relative brain volumes in a range overlapping those of bony fish as well as birds and mammals. Much of the variation is due to relative development of the telencephalon and cerebellum. Telencephalic weights vary from 24% in Squalus to 52% in Sphyrna . Analysis of the cytoarchitectonics of the shark brains reveals at least two patterns of development. Squalomorph sharks possess low brain:body ratios, and the telencephalon of these taxa possess well developed lateral ventricles and poorly developed pallial areas. The diencephalon is characterized by prominent periventricular laminae, and the cerebellum lacks foliation. The lamniform and carcharhiniform sharks are characterized by high brain: body ratios, and there is marked hypertrophy of the telencephalon. The roof (pallial) regions, as well as the diencephalon, are characterized by extensive cellular migrations. The cerebella of these forms possess extensive complex foliation.
These brain patterns are compared with the brain organization of Holocephali, and I conclude that the holocephalans are a sister radiation of the elasmobranchs. Comparisons with bony fish and land vertebrates suggest that elasmobranchs have independently developed complex pallial fields and cerebellar foliation as a result of parallel evolutionary trends.