Kirk E Christopher
Department of Anthropology, University of Texas, Austin, Texas 78712, USA.
Anat Rec A Discov Mol Cell Evol Biol. 2004 Nov;281(1):1095-103. doi: 10.1002/ar.a.20115.
Comparative studies of mammalian eye morphology have shown that relative cornea size is an important correlate of visual ecology. Nocturnal species tend to have large corneas relative to eye size as an adaptation for increasing visual sensitivity. By contrast, diurnal species tend to have smaller corneas relative to eye size because their eye morphology maximizes visual acuity. Although qualitative analyses suggest that activity pattern may have a similar influence on eye morphology in primates, various current hypotheses have proposed that either diurnal anthropoids or diurnal lemurs have visual systems that diverge from those of other diurnal mammals. The goal of this analysis is to quantify the relationship between eye morphology and activity pattern in primates and to determine whether primates exhibit variation in eye morphology comparable to that of other mammals. Data on eye size and cornea size were collected for 147 specimens of 55 primate species. These data reveal that, within primate suborders, diurnal species have significantly smaller relative cornea sizes than nocturnal or cathemeral species. Both haplorhines and strepsirrhines thus exhibit variation in eye morphology that is consistent with functional expectations. However, comparisons between the two primate suborders demonstrate that haplorhines and strepsirrhines differ significantly in eye morphology. Whereas strepsirrhines have relative cornea sizes that are similar to nonprimate mammals of comparable activity pattern, diurnal anthropoids have smaller relative cornea sizes than most nonprimate mammals. This derived eye morphology in anthropoids probably evolved in the anthropoid stem lineage as a result of selection for highly acute diurnal vision.
哺乳动物眼睛形态的比较研究表明，相对角膜大小是视觉生态学的一个重要相关因素。夜行性物种相对于眼睛大小往往具有较大的角膜，这是一种提高视觉敏感度的适应性特征。相比之下，昼行性物种相对于眼睛大小往往具有较小的角膜，因为它们的眼睛形态能使视觉敏锐度最大化。尽管定性分析表明活动模式可能对灵长类动物的眼睛形态有类似影响，但目前的各种假说提出，要么昼行性类人猿，要么昼行性狐猴的视觉系统与其他昼行性哺乳动物不同。本分析的目的是量化灵长类动物眼睛形态与活动模式之间的关系，并确定灵长类动物的眼睛形态变化是否与其他哺乳动物相当。收集了55种灵长类动物147个标本的眼睛大小和角膜大小数据。这些数据显示，在灵长类亚目内部，昼行性物种的相对角膜大小明显小于夜行性或晨昏性物种。因此，类人猿和原猴亚目在眼睛形态上都表现出与功能预期相符的变化。然而，两个灵长类亚目之间的比较表明，类人猿和原猴亚目在眼睛形态上有显著差异。原猴亚目的相对角膜大小与具有类似活动模式的非灵长类哺乳动物相似，而昼行性类人猿的相对角膜大小比大多数非灵长类哺乳动物小。类人猿这种特有的眼睛形态可能是在类人猿主干谱系中由于对高度敏锐的昼间视觉的选择而进化而来的。
