Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany.
Bavarian State Collection of Zoology - SNSB, Münchhausenstraße 21, 81247, Munich, Germany; Ludwig-Maximilians-Universität München, Department Biologie II, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany; GeoBioCenter(LMU), Richard -Wagner-Str. 10, 80333, Munich, Germany.
Arthropod Struct Dev. 2019 Jul;51:23-31. doi: 10.1016/j.asd.2019.06.002. Epub 2019 Jun 18.
Only a few studies have examined the central visual system of Thelyphonida (whip scorpions) until now. To obtain new insights suitable for phylogenetic analysis we studied the axonal trajectories and neuropil architecture of the central visual systems of two whip scorpion species (Mastigoproctus giganteus and Typopeltis dalyi) with different neuroanatomical techniques (Cobalt fills, Wigglesworth stains, and μCT). The central visual system of whip scorpion comprises one pair of median eyes and one pair of lateral eye triplets. The R-cells (or retinula cells) of both eye types each terminate in a first and a second visual neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual neuropil and terminate in the second and the first lateral eye neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap here. Additionally, the arcuate body and mushroom bodies are described. A detailed comparison of our findings with previously studied chelicerate central visual systems seems to support a monophyly of Arachnopulmonata, i.e. a clade comprising Tetrapulmonata (Thelyphonida, Schizomida, Amblypygi, and Araneae) and Scorpions. Furthermore, the architecture of the central visual systems hints at a close evolutionary relationship of Arachnopulmonata and Xiphosura.
迄今为止，仅有少数研究对栉角蜥目（鞭尾蝎）的中枢视觉系统进行了研究。为了获得适合系统发育分析的新见解，我们使用钴填充、威格尔斯沃思染色和μCT 等不同神经解剖技术研究了两种鞭尾蝎物种（Mastigoproctus giganteus 和 Typopeltis dalyi）的中枢视觉系统的轴突轨迹和神经丛结构。鞭尾蝎的中枢视觉系统包括一对中央眼和一对侧眼三对。两种眼型的 R 细胞（或视锥细胞）分别终止于第一和第二视觉神经丛。此外，从中眼离开的少数 R 细胞纤维第二中央眼视觉神经丛并终止于第二和第一侧眼神经丛。这意味着侧眼和中央眼的 R 细胞末端在这里重叠。此外，还描述了弓形体和蘑菇体。将我们的发现与先前研究的节肢动物中枢视觉系统进行详细比较，似乎支持蛛形类的单系性，即包括四足类（栉角蜥目、栉蚕目、鞭尾目和蜘蛛目）和蝎子的一个分支。此外，中枢视觉系统的结构暗示了蛛形类和鲎类之间的密切进化关系。
