Lyras George A, Giannakopoulou Aggeliki, Kouvari Miranda, Papadopoulos Georgios C
Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Zografos, Greece.
Brain Behav Evol. 2016;88(3-4):187-203. doi: 10.1159/000453104. Epub 2017 Jan 10.
The order Carnivora is a large and highly diverse mammalian group with a long and well-documented evolutionary history. Nevertheless, our knowledge on the degree of cortical folding (or degree of gyrification) is limited to just a few species. Here we investigate the degree of cortical folding in 64 contemporary and 37 fossil carnivore species. We do so by measuring the length of gyri impressions on endocranial casts. We use this approach because we have found that there is a very good correlation between the degree of cortical folding and the relative length of the gyri that are exposed on the outer surface of the hemispheres. Our results indicate that aquatic and semiaquatic carnivores have higher degrees of cortical folding than terrestrial carnivores. The degree of cortical folding varies among modern families, with viverrids having the lowest values. Furthermore, the scaling of cortical folding with brain size follows different patterns across specific carnivore families. Forty million years ago, the first carnivores had a relatively small cortex and limited cortical folding. Both the size of the cortex and the degree of cortical folding increased independently in each family during evolution.
食肉目是一个庞大且高度多样化的哺乳动物群体，拥有悠久且有充分文献记载的进化史。然而，我们对其皮质折叠程度（或脑回化程度）的了解仅限于少数几个物种。在此，我们研究了64种现代和37种化石食肉动物物种的皮质折叠程度。我们通过测量颅内腔模型上脑回印记的长度来进行研究。我们采用这种方法是因为我们发现皮质折叠程度与暴露在半球外表面的脑回相对长度之间存在非常好的相关性。我们的研究结果表明，水生和半水生食肉动物的皮质折叠程度高于陆生食肉动物。皮质折叠程度在现代科之间存在差异，灵猫科的值最低。此外，皮质折叠程度与脑大小的缩放关系在特定的食肉动物科中遵循不同的模式。四千万年前，第一批食肉动物的皮质相对较小且皮质折叠有限。在进化过程中，每个科的皮质大小和皮质折叠程度都是独立增加的。
