TESTING HISTORICAL HYPOTHESES OF MORPHOLOGICAL CHANGE: BIOMECHANICAL DECOUPLING IN LORICARIOID CATFISHES
TESTING HISTORICAL HYPOTHESES OF MORPHOLOGICAL CHANGE: BIOMECHANICAL DECOUPLING IN LORICARIOID CATFISHES
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检验形态变化的历史假说：菱形鲶鱼的生物力学解耦
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
G. Lauder
中科院分区：
文献类型：
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作者：
S. Schaefer;G. Lauder
“解耦假说”已被提出作为新型结构和功能演化的机制基础。解耦源于通过失去联系和/或将各个元素重复作为冗余设计组件来释放功能约束，然后是一个或多个元素的专门化。已经提出了针对几类生物体的非同构解耦的例子，然而，对于关于解耦的功能和形态后果的明确陈述的实证测试很少。使用金鲶鱼，我们测试了解耦的一个特定结果，即预测具有生物力学复杂性增加的解耦系统的进化枝将比不具有此类解耦系统的外群体表现出更大的相关结构形态变异性。基于地标间距离的形态测量程序用于量化 loricarioid 分支图中连续节点的三个设计水平的形态方差。使用额外的基于地标的程序来定位进化枝之间形状变化的主要模式。我们报告了与脱钩事件相关的谱系中所有三个形态水平的组内形态变异显着更大，证实了我们在脱钩假设下的预测。然而，12 次比较中有两次产生了显着的方差效应，而没有预测到这一点。形状变化主要模式的定位表明，形态和功能进化之间的分离可能导致这两个比较中方差预测和解耦之间缺乏拟合。
The “decoupling hypothesis” has been proposed as a mechanistic basis for the evolution of novel structure and function. Decoupling derives from the release of functional constraints via loss of linkages and/or repetition of individual elements as redundant design components, followed by specialization of one or more elements. Examples of apomorphic decoupling have been suggested for several groups of organisms, however there have been few empirical tests of explicit statements concerning functional and morphological consequences of decoupling. Using the loricarioid catfishes, we tested one particular consequence of decoupling, the prediction that clades possessing decoupled systems having increased biomechanical complexity will exhibit greater morphological variability of associated structures than outgroups having no such decoupled systems. Morphometric procedures based on interlandmark distances were used to quantify morphological variance at three levels of design at successive nodes in the loricarioid cladogram. Additional landmark‐based procedures were used to localize major patterns of shape change between clades. We report significantly greater within‐group morphometric variance at all three morphological levels in those lineages associated with decoupling events, confirming our predictions under the decoupling hypothesis. Two of 12 comparisons, however, yielded significant variance effects where none were predicted. Localization of the major patterns of shape change suggests that disassociation between morphological and functional evolution may contribute to the lack of fit between variance predictions and decoupling in these two comparisons.