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首页> 外文期刊>Transactions of the American Ophthalmological Society. >Evolutionary attempts at 4 eyes in vertebrates.
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Evolutionary attempts at 4 eyes in vertebrates.

机译：在脊椎动物中对四只眼的进化尝试。

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PURPOSE: To understand and compare the optical, histological, and ecological differences among 4 vertebrate species that have had evolutionary attempts toward 4 eyes. METHODS: An evolutionary attempt at 4 eyes in defined as the duplication or one or more structures integral to the refraction or interpretation of the visible spectrum for that animal. We reviewed and compared the known optics, histology, and ecology of each of these vertebrate species with attempts at 4 eyes including Anableps anableps, Dialomnus fuscus, Mnierpes macrocephalus, and Bathylychnops exilis. These animals have developed portions of ancillary eyes that have diverged from the primary globe in 3 different patterns. At least 1 specimen of each of those vertebrate species known to have 4 eyes was examined histologically and compared to the animal's ecology and current cladistic relationship. RESULTS: A anabteps has 2 distinct optical systems in each eye: an upper one for aerial vision and a lower system for aquatic vision. These systems feature separate retinae and an asymmetric lens to achieve focus in the aerial and aquatic vision, but only 1 optic nerve per eye. The visual system is split horizontally to function optimally in a prone vertically (almost perpendicular to the long axis of the fish) divided cornea using pigment and a condensation of collagen as the divider, a single pupil, and a divided retina. The split cornea allows for the fish to remain vertical with 1 cornea in air and 1 cornea in water. M macrocephalus is probably closely related to D fuscus with a similar split cornea. B exilis is a mesopelagic inhabitant living at approximately 200 to 1,000 m and has an ancillary globe that "buds" off the primary globe. This secondary globe is directed inferiorly toward the ocean floor as compared to the primary globe, which is directed 35 degrees superiorly from the horizontal. Adult species of B exilis have 2 additional scleral bodies suspected to be lenses. If so, these structures would be capable of focusing light from the inferior field onto the superior retina, presumably adding to the panoramic inferior visual field. There are other mesopelagic species, including Styleophorus chordatus, Opisthoproctus grimaldii, Scopelarchus gantheri (or guentheri), Dolichopteryx binocularis, Benthalbella infans, and Evermannella indica, that have other unusual ocular mechanisms, such as retinal diverticulae and lens pads capable of reflection, but do not meet the definition of multiple eyes, as defined for purposes of this work. CONCLUSIONS: D fuscus and M macrocephalus are terrestrial feeders requiring aquatic and aerial vision, and hence have a split cornea for this purpose, and they probably use their anterior corneae for terrestrial vision. A anableps swims at the surface with combined aerial and aquatic vision for feeding and protection from predators. B exilis is a mesopelagic feeder requiring a binocular visual field in the horizontal meridian and above, and simultaneously is a bottom scavenger using an ancillary globe and perhaps scleral lenses for recognition of bioluminescent detritus. Although 2 of these models are related (D fuscus and M macrocephalus), these 4 fish represent 3 separate, distinct, and unrelated convergent evolutionary attempts toward 4 eyes in vertebrates satisfying the ecological needs of each. The 3 different models are unrelated evolutionarily and are found in 3 separate orders.
机译：目的：了解和比较在4种眼睛中进行过进化尝试的4种脊椎动物之间的光学，组织学和生态学差异。方法：四只眼睛的进化尝试被定义为该动物重复或一个或多个结构折射或解释可见光谱。我们回顾并比较了每种脊椎动物的已知光学，组织学和生态学，并尝试了4只眼睛，包括An实，Dial实，白头M和裸眼Bath。这些动物的副眼部分已发育成从原球以三种不同的模式发散。对每只已知有4只眼睛的脊椎动物物种的至少1个标本进行了组织学检查，并将其与动物的生态学和当前的分类关系进行了比较。结果：一只肛门的每只眼睛有2个不同的光学系统：一个用于空中视觉的上光学系统和一个用于水生视觉的下光学系统。这些系统具有独立的视网膜和不对称晶状体，以实现空中和水生视觉的聚焦，但是每只眼睛只有1条视神经。视觉系统被水平分割，以在垂直（几乎垂直于鱼的长轴）的俯角垂直方向上发挥最佳功能，该垂直角膜使用色素和胶原蛋白的凝结物作为分隔物，单个瞳孔和分隔的视网膜。分开的角膜可使鱼保持垂直，空气中有1个角膜，水中有1个角膜。 M头畸形可能与D富拉斯有紧密的角膜相似关系。 B exilis是一个近中生的居民，生活在大约200到1,000 m之间，其附属地球仪从原始地球仪“预算”下来。与主要地球仪相比，该次要地球仪比海平面低35度。成年的B exilis物种还有2个怀疑为晶状体的巩膜小体。如果这样的话，这些结构将能够将来自下视野的光聚焦到视网膜上，大概会增加全景下视野。还有其他中古生种，包括索氏梭菌（Strophophus chordatus），格氏Opisthoproctus grimaldii，Scopelarchus gantheri（或guentheri），双翅目Dolichopteryx，Benthalbella infans和Evermannella indica，它们还有其他异常的眼部机制，例如视网膜反射性憩室和晶状体垫，不符合为此目的定义的多眼的定义。结论：D. Fuscus和M. macrocephalus是陆生食肉动物，需要水生和空中视觉，因此为此目的角膜已裂开，他们很可能将其前角膜用于陆地视觉。食蚁动物在地表游泳，具有空中和水上混合视觉，可以进食并提供保护，免受天敌的袭击。 B exilis是需要在水平子午线及上方的双目视野的中生动物饲养者，同时也是使用辅助球镜或巩膜片识别生物发光碎屑的底部清除剂。尽管这些模型中有2种是相关的（D fuscus和M macrocephalus），但是这4条鱼代表了满足4个眼睛的脊椎动物中3个单独，不同且无关的融合进化尝试，它们满足了每个动物的生态需求。这3种不同的模型在进化上不相关，并且以3个不同的顺序找到。

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