Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, 60438, Frankfurt am Main, Germany.
Ernst Strüngmann Institute for Neuroscience, Deutschordenstraße 46, 60528 Frankfurt am Main, Germany.
J Comp Neurol. 2019 Jan 1;527(1):13-37. doi: 10.1002/cne.24167. Epub 2017 Mar 10.
The lemurs of Madagascar (Primates: Lemuriformes) are a monophyletic group that has lived in isolation from other primates for about 50 million years. Lemurs have diversified into species with diverse daily activity patterns and correspondingly different visual adaptations. We assessed the arrangements of retinal cone and rod photoreceptors in six nocturnal, three cathemeral and two diurnal lemur species and quantified different parameters in six of the species. The analysis revealed lower cone densities and higher rod densities in the nocturnal than in the cathemeral and diurnal species. The photoreceptor densities in the diurnal Propithecus verreauxi indicate a less "diurnal" retina than found in other diurnal primates. Immunolabeling for cone opsins showed the presence of both middle-to-longwave sensitive (M/L) and shortwave sensitive (S) cones in most species, indicating at least dichromatic color vision. S cones were absent in Allocebus trichotis and Cheirogaleus medius, indicating cone monochromacy. In the Microcebus species, the S cones had an inverse topography with very low densities in the central retina and highest densities in the peripheral retina. The S cones in the other species and the M/L cones in all species had a conventional topography with peak densities in the central area. With the exception of the cathemeral Eulemur species, the eyes of all studied taxa, including the diurnal Propithecus, possessed a tapetum lucidum, a feature only found among nocturnal and crepuscular mammals.
马达加斯加狐猴（灵长目：狐猴目）是一个单系群，已经与其他灵长类动物隔离了大约 5000 万年。狐猴已经多样化为具有不同日常活动模式和相应不同视觉适应的物种。我们评估了六种夜行性、三种昼行性和两种日行性狐猴物种的视网膜锥体细胞和杆体细胞感受器的排列，并在六种物种中量化了不同的参数。分析表明，夜行性物种的锥体细胞密度较低，而杆体细胞密度较高。日行性的Propithecus verreauxi 的光感受器密度表明其视网膜比其他日行性灵长类动物的“昼行性”程度更低。锥体细胞视蛋白的免疫标记显示，大多数物种都存在中长波敏感（M/L）和短波敏感（S）锥体细胞，表明至少具有双色视觉。Allocebus trichotis 和 Cheirogaleus medius 中不存在 S 锥体细胞，表明锥体细胞单色性。在 Microcebus 物种中，S 锥体细胞的拓扑结构相反，在中央视网膜的密度非常低，而在周边视网膜的密度最高。其他物种的 S 锥体细胞和所有物种的 M/L 锥体细胞的拓扑结构具有典型的中央区域峰值密度。除了昼行性的 Eulemur 物种外，所有研究的类群的眼睛，包括日行性的 Propithecus，都具有明毯，这是仅在夜行性和黄昏哺乳动物中发现的特征。
