Department of Geological Sciences, Jackson School of Geological Sciences, The University of Texas at Austin, Austin, Texas, USA.
Anat Rec (Hoboken). 2010 Nov;293(11):1896-912. doi: 10.1002/ar.21234.
Ontogeny, or the development of an individual from conception to death, is a major source of variation in vertebrate morphology. All anatomical systems are affected by ontogeny, and knowledge of the ontogenetic history of these systems is important to understand when formulating biological interpretations of evolutionary history and physiology. The present study is focused on how variation affects the bony labyrinth across a growth series of an extant mammal after ossification of the inner ear chambers. Digital endocasts of the bony labyrinth were constructed using CT data across an ontogenetic sequence of Monodelphis domestica, an important experimental animal. Various aspects of the labyrinth were measured, including angles between the semicircular canals, number of turns of the cochlea, volumes of inner ear constituents, as well as linear dimensions of semicircular canals. There is a strong correlation between skull length and age, but from 27 days after birth onward, there is no correlation with age among most of the inner ear measurements. Exceptions are the height of the arc of the lateral semicircular canal, the angular deviation of the lateral canal from planarity, the length of the slender portion of the posterior semicircular canal, and the length of the canaliculus cochleae. Adult dimensions of several of the inner ear structures, such as the arcs of the semicircular canals, are achieved before the inner ear is functional, and the non-ontogenetic variation in the bony labyrinth serves as an important source for behavioral, physiological, and possibly phylogenetic information.
个体的发生发育，即从受孕到死亡的个体发育，是脊椎动物形态变异的主要来源。所有的解剖系统都受到个体发育的影响，了解这些系统的个体发育历史对于理解进化历史和生理学中的生物解释非常重要。本研究主要关注的是在现生哺乳动物的内耳室骨化后，变异如何影响骨质迷路在生长系列中的变化。使用 Monodelphis domestica 的 CT 数据构建了骨质迷路的数字内耳道模型，该动物是一种重要的实验动物。测量了迷路的各个方面，包括半规管之间的角度、耳蜗的匝数、内耳成分的体积以及半规管的线性尺寸。头骨长度与年龄之间存在很强的相关性，但从出生后 27 天开始，大多数内耳测量值与年龄之间没有相关性。例外的是外侧半规管的弧形高度、外侧管从平面的角度偏差、后半规管细长部分的长度以及耳蜗小管的长度。几个内耳结构的成年尺寸，如半规管的弧形，在内耳具有功能之前就已经达到，骨质迷路的非个体发育变异为行为、生理和可能的系统发育信息提供了重要来源。
