Phylogenetic signal analysis in the basicranium of Ursidae (Carnivora, Mammalia)
Phylogenetic signal analysis in the basicranium of Ursidae (Carnivora, Mammalia)
复制标题
熊科（食肉目、哺乳动物）基壳的系统发育信号分析
作者：
M. Arnaudo;Néstor Toledo;L. Soibelzon;Paula Bona
熊科是一个单系群，由三个亚科组成：Tremartinae，Ursinae和Ailuropodinae，它们都有丰富的地理分布。熊科群内的系统发育关系一直未被充分研究，特别是关于形态特征，如基颅。重要的是，颅底是一个高度复杂的区域，覆盖了头骨的一小部分，结合了决定其形态的结构和功能方面。熊科（包括Tremartinae）的系统发育假设是基于头骨，下颌骨和牙齿特征的形态特征，而听觉区和基颅的特征尚未考虑在内。要做到这一点，我们分析的形状和大小宏观演化的熊科的basicranium，测试其形态差异的系统发育背景下，这是量化的系统发育信号。我们研究了遗传自相关的形状（描述的主成分分析得分从以前发表的分析）和basicranium大小（描述的质心大小，CS）使用正交分解分析和Abouheif C均值。这些方法的主要优点是，它们完全依赖于分支图拓扑结构，不需要分支长度估计。此外，使用TNT 1.5软件进行祖先节点的优化。在系统发育信号方面，两种方法显示出相似的结果：在PC 1和PC 2中检测到自相关的存在，而在PC 3，PC 4和PC 5以及基颅（CS）的大小中，不存在自相关。最重要的节点（存在自相关性）是基底节点“Ursidae”和“Ursinae-Tremartinae”。在这最后一组中，观察到独特的基颅形态，在Tremartinae比Ursinae更保守。这些亚科之间的差异可能与涉及不同食物和环境偏好的历史事件有关。在节点Tremartinae的高系统发育信号可能表明，这些熊的basicranium配置早期在其进化历史。最后，我们的研究结果的基颅和头骨长度的比例表明，在Tremartinae，基颅的大小是不是决定的繁殖，而是由其他因素，如适应气候变化的反应和竞争与其他食肉动物。
Ursidae is a monophyletic group comprised of three subfamilies: Tremarctinae, Ursinae and Ailuropodinae, all of which have a rich geographical distribution. The phylogenetic relationships within the Ursidae group have been underexamined, especially regarding morphological traits such as the basicranium. Importantly, the basicranium is a highly complex region that covers a small portion of the skull, combining both structural and functional aspects that determine its morphology. Phylogenetic hypotheses of the Ursidae (including Tremarctinae) have been made based on morphological characters that considers skull, mandible and teeth features, while specific characters of the auditory region and basicranium have not been taken into account. To do this, we analyse the shape and size macroevolution of the basicranium of Ursidae, testing its morphological disparity in a phylogenetic context, which is quantified by means of the phylogenetic signal. We investigated phylogenetical autocorrelation by shape (depicted by Principal Components Analysis scores from previous published analyses) and basicranium size (depicted by centroid size, CS) using an orthonormal decomposition analysis and Abouheif C mean. The main advantages of these methods are that they rely exclusively on cladogram topology and do not require branch-length estimates. Also, an optimisation of the ancestral nodes was performed using TNT 1.5 software. In relation to the phylogenetic signal, both methods showed similar results: the presence of autocorrelation was detected in PC1 and PC2, while in PC3, PC4 and PC5 and in the size of the basicranium (CS), the absence of autocorrelation occurred. The most significant nodes (where there is autocorrelation) are the basal nodes ‘Ursidae’ and ‘Ursinae-Tremarctinae’. Within this last group, distinctive basicranium morphology is observed, being more conservative in Tremarctinae than in Ursinae. The differences between these subfamilies could be related to historical events involving varying food and environmental preferences. The high phylogenetic signal in the node Tremarctinae probably indicates that the basicranium configuration of these bears was obtained early in their evolutionary history. Finally, our results of the basicranium and skull length ratios indicate that in Tremarctinae, the basicranium size was not determined by phylogeny but instead by other factors, such as adaptive responses to climatic changes and competition with other carnivores.
DOI：
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发表时间：
2008
期刊：
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影响因子：
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作者：
Tina Unger;Anna-Sapfo Malaspinas;L. Soibelzon;P. Dear;G. Rabeder;P. Matheus;M. Hofreiter
通讯作者：
Tina Unger;Anna-Sapfo Malaspinas;L. Soibelzon;P. Dear;G. Rabeder;P. Matheus;M. Hofreiter