Brain Size and Brain Organization of the Whale Shark, Rhincodon typus, Using Magnetic Resonance Imaging
Brain Size and Brain Organization of the Whale Shark, Rhincodon typus, Using Magnetic Resonance Imaging
复制标题
使用磁共振成像研究鲸鲨（犀牛鲨）的大脑大小和大脑组织
DOI：
10.1159/000235962
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Frank, Lawrence R.
中科院分区：
文献类型：
--
作者：
Yopak, Kara E.;Frank, Lawrence R.
人们对吸滤食动物Rhincodon typus的大脑组织知之甚少，也不知道它与其他双形目动物相比如何专门作为浮游生物进食者。在两个标本的R的脑大小和整体脑组织进行了评估。用磁共振成像（MRI）技术，对与胚胎发育和生态学有关的类型进行了研究。与其他60多种软骨鱼类相比，R.典型鱼的脑相对于其身体大小（以脑化率和残留物表示）而言相对较小，类似于板形鱼Carcharodon carrusas、Cetorhinus maximus和Carrusas taurus。除了间脑相对较大和中脑相对较小之外，typus还具有相对较小的端脑和一些背侧软腭的发育，这暗示了适度的社会行为。最显著的特征是一个大的和高度叶状的小脑，软骨鱼类分支中最大的小脑之一。早期发展的大脑进行了定性评估使用原位MRI扫描的大脑和软骨颅骨的新生儿标本ofR。打字。有证据表明，小脑体的折叠出现在早期的发展，虽然褶皱的深度和数量可能会有所不同，在这个物种的个体发育。层次聚类分析和多维标度排序显示收敛进化的证据与姥鲨，Cetorhinus maximus，另一个大型的过滤器喂养板鳃类，支持的说法，即组织的大脑是更相似的物种具有类似的，但独立进化的生活方式比那些共享分类学分类。
Very little is known about the brain organization of the suction filter feeder,Rhincodon typus, and how it compares to other orectolobiforms in light of its specialization as a plankton-feeder. Brain size and overall brain organization was assessed in two specimens ofR. typusin relation to both phylogeny and ecology, using magnetic resonance imaging (MRI). In comparison to over 60 other chondrichthyan species,R. typusdemonstrated a relatively small brain for its body size (expressed in terms of encephalization quotients and residuals), similar to the lamniformsCarcharodon carcharias,Cetorhinus maximus, andCarcharias taurus.R. typuspossessed a relatively small telencephalon with some development of the dorsal pallium, which was suggestive of moderate social behavior, in addition to a relatively large diencephalon and a relatively reduced mesencephalon. The most notable characteristic of the brain ofRhincodonwas a large and highly foliated cerebellum, one of the largest cerebellums within the chondrichthyan clade. Early development of the brain was qualitatively assessed using an in situ MRI scan of the brain and chondrocranium of a neonate specimen ofR. typus. There was evidence that folding of the cerebellar corpus appeared in early development, although the depth and number of folds might vary ontogenetically in this species. Hierarchical cluster analysis and multidimensional scaling ordinations showed evidence of convergent evolution with the basking shark,Cetorhinus maximus, another large-bodied filter feeding elasmobranch, supporting the claim that organization of the brain is more similar in species with analogous but independently evolved lifestyles than those that share taxonomic classification.