Kröger Ronald H H, Gustafsson Ola S E, Tuminaite Inga
Department of Biology, Lund University, 223 62 Lund, Scania, Sweden.
J Morphol. 2014 Jun;275(6):613-22. doi: 10.1002/jmor.20240. Epub 2013 Dec 10.
We have investigated the apparatus suspending the crystalline lens in the eyes of basal vertebrates. Data are presented for Holocephali (Chondrichthyes) and the actinopterygians Polypteriformes, Polyodontidae (Acipenseriformes), Lepisosteiformes, Amiiformes, and one teleost species, the banded archerfish (Toxotes jaculatrix). We also studied the optical properties of the lens in Polypteriformes, Lepisosteiformes, and the archerfish. Together with previously published results, our findings show that there are three basic types of lens suspension in vertebrates. These are i) a rotationally symmetric suspension (Petromyzontida, lampreys; Ceratodontiformes, lungfishes; Tetrapoda), ii) a suspension with a dorso-ventral axis of symmetry and a ventral papilla (all Chondrichthyes and Acipenseriformes), and iii) an asymmetric suspension with a ventral muscle and a varying number of ligaments (all Actinopterygii except for Acipenseriformes). Large eyes with presumably high spatial resolution have evolved in all groups. Multifocal lenses creating well-focused color images are also present in all groups studied. Stable and exact positioning of the lens, in many cases in combination with accommodative changes in lens position or shape, is achieved by all three types of lens suspension. It is somewhat surprising that lens suspensions are strikingly similar in Chondrichthyes and Acipenseriformes (Actinopterygii), while the suspension apparatus in Polypteriformes, usually being regarded as an actinopterygian group more basal than Acipenseriformes, are considerably more teleostean-like. This study completes a series of investigations on lens suspensions in nontetrapod vertebrates, covering all major groups except for the rare and highly derived coelacanths.
我们研究了基底脊椎动物眼中悬吊晶状体的结构。文中给出了全头亚纲（软骨鱼纲）以及硬骨鱼纲的多鳍鱼目、匙吻鲟科（鲟形目）、雀鳝目、弓鳍鱼目和一种硬骨鱼——条纹射水鱼（眼斑射水鱼）的数据。我们还研究了多鳍鱼目、雀鳝目和射水鱼晶状体的光学特性。结合此前发表的研究结果，我们的发现表明脊椎动物的晶状体悬吊结构有三种基本类型。它们分别是：i）旋转对称悬吊结构（盲鳗纲，七鳃鳗；角齿鱼目，肺鱼；四足动物），ii）具有背腹对称轴和腹侧乳头的悬吊结构（所有软骨鱼纲和鲟形目），以及iii）具有腹侧肌肉和数量不等的韧带的不对称悬吊结构（除鲟形目外的所有硬骨鱼纲）。所有类群都进化出了可能具有高空间分辨率的大眼睛。在所有研究的类群中也都存在能形成聚焦良好的彩色图像的多焦点晶状体。这三种类型的晶状体悬吊结构在许多情况下通过晶状体位置或形状的适应性变化，实现了晶状体的稳定且精确的定位。有点令人惊讶的是，软骨鱼纲和鲟形目（硬骨鱼纲）的晶状体悬吊结构惊人地相似，而通常被认为是比鲟形目更原始的硬骨鱼纲类群的多鳍鱼目的悬吊结构却更类似于硬骨鱼。本研究完成了对非四足脊椎动物晶状体悬吊结构的一系列调查，涵盖了除罕见且高度特化的腔棘鱼之外的所有主要类群。
