The optics of the growing lungfish eye:: Lens shape, focal ratio and pupillar, movements in Neoceratodus forsteri (Krefft, 1870)
The optics of the growing lungfish eye:: Lens shape, focal ratio and pupillar, movements in Neoceratodus forsteri (Krefft, 1870)
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DOI：
10.1017/s0952523807070381
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发表时间：
2007-05-01
影响因子：
1.9
通讯作者：
Collin, Shaun P.
中科院分区：
文献类型：
--
作者：
Bailes, Helena J.;Trezise, Ann E. O.;Collin, Shaun P.
肺鱼（Dipnoi目）在泥盆纪时期进化，被认为是陆地脊椎动物最接近的亲属。在这里，我们描述了以前未知的形态的肺鱼眼睛，以检查眼适应目前在早期sarcopterygian鱼。与许多硬骨鱼不同的是，澳大利亚肺鱼新角龙（Neoceratodus）拥有一个移动的瞳孔，瞳孔反应缓慢，类似于两栖动物。从幼年到成年，眼睛的结构发生变化，随着生长，眼睛和透镜的形状变得更加椭圆。这种结构变化导致成鱼焦比（从透镜中心到视网膜的距离除以透镜半径）降低和视网膜照明增加。尽管对球面像差进行了一定程度的透镜校正，但在整个透镜上存在相当大的变化。重新计算的空间分辨能力，使用测得的焦比冷冻切片揭示了一个低的能力，以区分精细的细节。与大多数硬骨鱼类的眼睛相比，双眼龙的眼睛与两栖类的眼睛有更多的共同特征，这可能与这种活化石的视觉需求相呼应。
Lungfish (order Dipnoi) evolved during the Devonian period and are believed to be the closest living relatives to the land vertebrates. Here we describe the previously unknown morphology of the lungfish eye in order to examine ocular adaptations present in early sarcopterygian fish. Unlike many teleosts, the Australian lungfish Neoceratodus,forsteri possesses a mobile pupil with a slow pupillary response similar to amphibians. The structure of the eye changes from juvenile to adult, with both eye and lens becoming more elliptical in shape with growth. This change in structure results in a decrease in focal ratio (the distance from lens center to the retina divided by the lens radius) and increased retinal illumination in adult fish. Despite a degree of lenticular correction for spherical aberration, there is considerable variation across the lens. A re-calculation of spatial resolving power using measured focal ratios from cryosectioning reveals a low ability to discriminate fine detail. The dipnoan eye shares more features with amphibian eyes than with most teleost eyes, which may echo the visual needs of this living fossil.