Pfaff Cathrin, Martin Thomas, Ruf Irina
Department of Palaeontology, Geozentrum, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, Bonn 53115, Germany.
Proc Biol Sci. 2015 Jun 22;282(1809):20150744. doi: 10.1098/rspb.2015.0744.
The semicircular canals (SCs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. Based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. Our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. The morphometric anatomy of the SCs was correlated to the locomotion mode. Even if the phylogenetic signal cannot entirely be excluded, the main significance for functional morphological studies has been found in the diameter of the SCs, whereas the radius of curvature is of minor interest. Additionally, we found clear differences in the bias angle of the canals between subterranean and gliding taxa, but also between sciurids and glirids. The sensitivity of the inner ear correlates with the locomotion mode, with a higher sensitivity of the SCs in fossorial species than in flying taxa. We conclude that the inner ear of flying and gliding mammals is less sensitive due to the large information flow into this sense organ during locomotion.
内耳的半规管可检测角加速度，位于颞骨的骨迷路中。基于高分辨率计算机断层扫描，我们创建了一个与大小无关的数据库，涵盖50种哺乳动物的骨迷路，尤其是松鼠相关分支的啮齿动物，包括具有穴居、树栖和滑翔适应性的分类群。我们的样本还包括滑翔有袋动物、活跃飞行的蝙蝠、树栖的树鼩和地下物种。半规管的形态计量解剖学与运动模式相关。即使不能完全排除系统发育信号，但在功能形态学研究中，半规管的直径具有主要意义，而曲率半径的重要性较小。此外，我们发现地下类群和滑翔类群之间，以及松鼠科和睡鼠科之间，半规管的偏角存在明显差异。内耳的敏感性与运动模式相关，穴居物种的半规管敏感性高于飞行类群。我们得出结论，飞行和滑翔哺乳动物的内耳敏感性较低，这是因为在运动过程中有大量信息流进入这个感觉器官。
