Evolution of brain size in the palaeognath lineage, with an emphasis on new Zealand ratites
Evolution of brain size in the palaeognath lineage, with an emphasis on new Zealand ratites
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DOI：
10.1159/000111456
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发表时间：
2008-01-01
影响因子：
1.7
通讯作者：
Kubke, M. Fabiana
中科院分区：
文献类型：
--
作者：
Corfield, Jeremy R.;Wild, J. Martin;Kubke, M. Fabiana
脊椎动物的大脑大小主要随身体大小而变化。虽然许多研究已经研究了鸟类大脑大小的变化，但关于古脊椎动物的信息很少，包括猕猴桃、麋鹿、鸵鸟和已灭绝的MOA的平坦血统，以及锡婚制。因此，我们试图通过分析几种不同物种的大脑和大脑半球的相对大小的变化，来确定古脊椎动物大脑大小的进化在多大程度上与其他鸟类(即新脊椎动物)相似。我们的结果表明，除了猕猴桃辐射(Apteryx spp.)外，古龙虾的大脑和大脑半球比新龙虾相对较小。Apteryx的外部形态和相对较大的脑体积，以及其相对较大的端脑，与其他古食人形成对比，包括两种历史上共域的MOMA，这表明猕猴桃进化过程中伴随着独特的脑大小增加的选择压力。事实上，猕猴桃大脑半球的大小相对于总的大脑大小来说，只有少数几只鹦鹉和鸣禽可以与之匹敌，尽管缺乏任何证据表明有任何高级的行为/认知能力，比如报道的鹦鹉和乌鸦的能力。此外，尽管猕猴桃是一种早熟鸟类，但它的大脑和端脑的大小都会增大。这些发现是对目前控制鸟类大脑相对大小变化的规则的例外，因此也是对这一规则的挑战。版权所有(C)2007 S.Karger AG，巴塞尔。
Brain size in vertebrates varies principally with body size. Although many studies have examined the variation of brain size in birds, there is little information on Palaeognaths, which include the ratite lineage of kiwi, emu, ostrich and extinct moa, as well as the tinamous. Therefore, we set out to determine to what extent the evolution of brain size in Palaeognaths parallels that of other birds, i. e., Neognaths, by analyzing the variation in the relative sizes of the brain and cerebral hemispheres of several species of ratites and tinamous. Our results indicate that the Palaeognaths possess relatively smaller brains and cerebral hemispheres than the Neognaths, with the exception of the kiwi radiation (Apteryx spp.). The external morphology and relatively large size of the brain of Apteryx, as well as the relatively large size of its telencephalon, contrast with other Palaeognaths, including two species of historically sympatric moa, suggesting that unique selective pressures towards increasing brain size accompanied the evolution of kiwi. Indeed, the size of the cerebral hemispheres with respect to total brain size of kiwi is rivaled only by a handful of parrots and songbirds, despite a lack of evidence of any advanced behavioral/ cognitive abilities such as those reported for parrots and crows. In addition, the enlargement in brain and telencephalon size of the kiwi occurs despite the fact that this is a precocial bird. These findings form an exception to, and hence challenge, the current rules that govern changes in relative brain size in birds. Copyright (c) 2007 S. Karger AG, Basel.