Anthropologisches Institut und Museum, Universität Zürich-Irchel, Zürich, Switzerland.
J Anat. 2010 Mar;216(3):368-80. doi: 10.1111/j.1469-7580.2009.01177.x. Epub 2009 Dec 21.
The cavity system of the inner ear of mammals is a complex three-dimensional structure that houses the organs of equilibrium and hearing. Morphological variation of the inner ear across mammals reflects differences in locomotor behaviour and hearing performance, and the good preservation of this structure in many fossil specimens permits analogous inferences. However, it is less well known to what extent the morphology of the bony labyrinth conveys information about the evolutionary history of primate taxa. We studied this question in strepsirrhine primates with the aim to assess the potential and limitations of using the inner ear as a phylogenetic marker. Geometric morphometric analysis showed that the labyrinthine morphology of extant strepsirrhines contains a mixed locomotor, allometric and phylogenetic signal. Discriminant analysis at the family level confirmed that labyrinthine shape is a good taxonomic marker. Our results support the hypothesis that evolutionary change in labyrinthine morphology is adequately described with a random walk model, i.e. random phenotypic dispersal in morphospace. Under this hypothesis, average shapes calculated for each node of the phylogenetic tree give an estimate of inner ear shapes of the respective last common ancestors (LCAs), and this information can be used to infer character state polarity. The labyrinthine morphology of the fossil Adapinae is close to the inferred basal morphology of the strepsirrhines. The inner ear of Daubentonia, one of the most derived extant strepsirrhines, is autapomorphic in many respects, but also presents unique similarities with adapine labyrinths.
哺乳动物内耳的腔室系统是一个复杂的三维结构，其中包含平衡和听觉器官。内耳在哺乳动物中的形态变化反映了运动行为和听觉性能的差异，并且该结构在许多化石标本中的良好保存允许进行类似的推断。然而，内耳形态在多大程度上反映了灵长类动物进化历史的信息，这一点知之甚少。我们在食虫目灵长类动物中研究了这个问题，目的是评估将内耳作为系统发育标记的潜力和局限性。几何形态测量分析表明，现存食虫目灵长类动物的迷路形态包含混合的运动学、比例和系统发育信号。在科水平上的判别分析证实了迷路形状是一个很好的分类标记。我们的研究结果支持这样一种假设，即迷路形态的进化变化可以用随机游走模型来充分描述，即在形态空间中随机的表型分散。在这种假设下，为系统发育树的每个节点计算的平均形状给出了相应的最近共同祖先（LCA）内耳形状的估计值，并且可以利用这些信息来推断特征状态极性。化石 Adapinae 的迷路形态与食虫目灵长类动物的推断基态形态非常接近。现存最衍生的食虫目灵长类动物之一 Daubentonia 的内耳在许多方面是独特的，但也与 adapine 迷路具有独特的相似之处。
