Coleman Mark N, Ross Callum F
Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York 11794, USA.
Anat Rec A Discov Mol Cell Evol Biol. 2004 Nov;281(1):1123-37. doi: 10.1002/ar.a.20118.
The auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and evolutionary consequences of these and other auditory features. The dimensions of the outer ear (pinna) were measured in cadaveric specimens representing nearly every primate family and used to calculate a shape ratio (height/width). It was found that nonanthropoids have a significantly higher ratio than anthropoids, although the actual height was not found to differ. This indicates that most nonanthropoids have ears that are tall and narrow, whereas monkeys and apes are characterized by ears with more equal height and width dimensions. Eardrum area, stapedial footplate area, and ossicular lever arm lengths were measured in dried specimens to calculate an impedance transformer ratio. A distinction was found between anthropoids and strepsirrhines, with the latter group having a transformer ratio indicative of a higher percentage of acoustic energy transmission through the middle ear. Audiogram data were gathered from the literature to analyze hearing sensitivity and it was found that platyrrhines illustrate more low-frequency sensitivity than like-sized lorisoids. The effects of intraspecific variation on the audiogram results were also examined and were found to produce similar results as the analysis using species mean threshold values. Lastly, correlations between morphological and audiogram variables were examined. Several measures of hearing sensitivity were found to be correlated with pinna shape but correlations with middle ear transmission properties were weaker. In addition to using traditional statistical techniques, phylogenetic corrective methods were applied to address the problem of statistical nonindependence of the data and the results of both analyses are compared. These findings are discussed with respect to how sensory adaptations and phylogenetic history may be related to the current radiation of primates.
听觉区域包含许多结构，这些结构已被证明在不同分类水平的系统发育分类中很有用。然而，在灵长类动物中，将形态差异与听力表现变化相关联的工作做得很少。本研究记录了灵长类动物内部的解剖学和生理学差异，并开始探讨这些以及其他听觉特征的功能和进化后果。在代表几乎每个灵长类动物科的尸体标本中测量了外耳（耳廓）的尺寸，并用于计算形状比（高度/宽度）。结果发现，非类人猿的形状比明显高于类人猿，尽管实际高度没有差异。这表明大多数非类人猿的耳朵又高又窄，而猴子和猿类的耳朵特征是高度和宽度尺寸更相等。在干燥标本中测量鼓膜面积、镫骨足板面积和听骨杠杆臂长度，以计算阻抗变压器比。在类人猿和原猴亚目之间发现了差异，后一组的变压器比表明通过中耳传输的声能百分比更高。从文献中收集听力图数据以分析听力敏感度，发现阔鼻猴类比体型相似的懒猴科动物表现出更高的低频敏感度。还研究了种内变异对听力图结果的影响，发现其产生的结果与使用物种平均阈值的分析结果相似。最后，研究了形态学和听力图变量之间的相关性。发现几种听力敏感度测量值与耳廓形状相关，但与中耳传输特性的相关性较弱。除了使用传统统计技术外，还应用了系统发育校正方法来解决数据统计非独立性问题，并比较了两种分析的结果。就感觉适应和系统发育历史如何可能与灵长类动物当前的辐射相关这一问题对这些发现进行了讨论。
