Ramm Till, Scholtz Gerhard
Humboldt-Universität zu Berlin, Institut für Biologie, Vergleichende Zoologie, Philippstr. 13, 10115 Berlin, Germany.
Humboldt-Universität zu Berlin, Institut für Biologie, Vergleichende Zoologie, Philippstr. 13, 10115 Berlin, Germany.
Arthropod Struct Dev. 2017 Jul;46(4):537-551. doi: 10.1016/j.asd.2017.03.003. Epub 2017 Apr 20.
The brain anatomy of Niphargus puteanus and Orchestia cavimana, two amphipod species with different lifestyles, has been studied using a variety of recent techniques. The general aspects of the brain anatomy of both species correspond to those of other malacostracans. However, both species lack hemiellipsoid bodies. Furthermore, related to their lifestyle certain differences have been observed. The aquatic subterranean species N. puteanus lacks eye structures, the optic nerve, and the two outer optic neuropils lamina and medulla. Only partial remains of the lobula have been detected. In contrast to this, the central complex in the protocerebrum and the olfactory glomeruli in the deutocerebrum are well differentiated. The terrestrial species Orchestia cavimana shows a reduced first antenna, the absence of olfactory neuropils in the deutocerebrum, and a reduction of the olfactory globular tract. The characteristics in defining the hemiellipsoid bodies are critically discussed. Contradictions about presence or absence of this neuropil are due to different conceptualizations. A comparison with other crustaceans that live in dark environments reveal similar patterns of optic system reduction, but to different degrees following a centripetal pattern. Retaining the olfactory system seems a general problem of terrestrialization in crustaceans with the notable exception of terrestrial hermit crabs.
利用多种最新技术，对两种具有不同生活方式的端足类动物——波氏新米虾（Niphargus puteanus）和海滨钩虾（Orchestia cavimana）的脑解剖结构进行了研究。这两种物种脑解剖结构的一般特征与其他软甲亚纲动物的特征相符。然而，这两种物种都没有半椭球体。此外，根据它们的生活方式，还观察到了一些差异。水生地下物种波氏新米虾没有眼睛结构、视神经以及两个外侧视神经纤维层和髓质。仅检测到了小叶的部分残余。与此相反，原脑的中央复合体和中脑的嗅觉小球分化良好。陆生物种海滨钩虾的第一触角退化，中脑没有嗅觉神经纤维层，嗅觉球状束也退化。对定义半椭球体的特征进行了批判性讨论。关于这个神经纤维层存在与否的矛盾是由于不同的概念化。与生活在黑暗环境中的其他甲壳类动物的比较显示，视觉系统的退化模式相似，但遵循向心模式的程度不同。保留嗅觉系统似乎是甲壳类动物陆地化的一个普遍问题，但陆地寄居蟹是个明显的例外。
