Kemp A
Griffith School of Environment and the School of Biomolecular and Physical Sciences, Griffith University, 170 Kessels Road, Nathan, Brisbane, Queensland 4111, Australia.
Tissue Cell. 2017 Feb;49(1):45-55. doi: 10.1016/j.tice.2016.11.009. Epub 2016 Dec 9.
Three systems, two sensory and one protective, are present in the skin of the living Australian lungfish, Neoceratodus forsteri, and in fossil lungfish, and the arrangement and innervation of the sense organs is peculiar to lungfish. Peripheral branches of nerves that innervate the sense organs are slender and unprotected, and form before any skeletal structures appear. When the olfactory capsule develops, it traps some of the anterior branches of cranial nerve V, which emerged from the chondrocranium from the lateral sphenotic foramen. Cranial nerve I innervates the olfactory organ enclosed within the olfactory capsule and cranial nerve II innervates the eye. Cranial nerve V innervates the sense organs of the snout and upper lip, and, in conjunction with nerve IX and X, the sense organs of the posterior and lateral head. Cranial nerve VII is primarily a motor nerve, and a single branch innervates sense organs in the mandible. There are no connections between nerves V and VII, although both emerge from the brain close to each other. The third associated system consists of lymphatic vessels covered by an extracellular matrix of collagen, mineralised as tubules in fossils. Innervation of the sensory organs is separate from the lymphatic system and from the tubule system of fossil lungfish.
现存的澳大利亚肺鱼（Neoceratodus forsteri）以及化石肺鱼的皮肤中存在三种系统，其中两种是感觉系统，一种是保护系统，感觉器官的排列和神经支配是肺鱼所特有的。支配感觉器官的神经外周分支纤细且无保护，在任何骨骼结构出现之前就已形成。当嗅囊发育时，它会捕获一些从软骨颅的外侧蝶骨孔穿出的三叉神经（V）的前支。嗅神经（I）支配包裹在嗅囊内的嗅觉器官，视神经（II）支配眼睛。三叉神经（V）支配吻部和上唇的感觉器官，并与舌咽神经（IX）和迷走神经（X）一起支配头部后部和侧面的感觉器官。面神经（VII）主要是运动神经，其单个分支支配下颌中的感觉器官。虽然三叉神经（V）和面神经（VII）都从大脑中彼此靠近的位置发出，但它们之间没有连接。第三个相关系统由被胶原蛋白细胞外基质覆盖的淋巴管组成，在化石中这些淋巴管矿化形成小管。感觉器官的神经支配与淋巴系统以及化石肺鱼的小管系统是分开的。
