From water to land: the ontogeny of Persian mudskippers

从水生生活方式向陆地生活方式的转变是脊椎动物进化中最具挑战性的事件之一，为从鱼类祖先进化而来的四足动物入侵陆地扫清了道路。这种环境转变需要适应许多功能系统，从呼吸和运动到从水中摄取食物。然而，四足动物并不是唯一进化出半陆地形式和陆地适应的脊椎动物，它们独立地出现在不同的放线蕨类群中。其中最著名的例子之一是哥比状的泥嘴鱼(Oxudercinae)，它们最初是远洋幼虫，后来蜕变成半陆生形式，在陆地上度过了高达90%的活跃生命。因此，弹涂鱼提供了一种独特的可能性来研究其个体发育过程中从水生生物向陆地生物过渡所要求的功能适应，这是与四足动物历史平行的现象。到目前为止，从陆地适应的角度研究变质后的弹涂鱼物种很少，对其幼虫的生物学和解剖学或变态过程中的戏剧性重塑的了解就更少了。在这里，我们提出了一个项目，旨在收集伊朗盖什姆岛红树林中三种研究较少的弹涂鱼的幼虫和成虫阶段，以研究呼吸系统、摄食装置和运动系统的变态变化。

Transitions from aquatic to terrestrial lifestyles were amongst the most challenging events in vertebrate evolution and cleared the way for the invasion of land by tetrapods which developed from fish-like ancestors. Such environmental transitions demand adaptations of many functional systems, from breathing and locomotion up to feeding out of water. Tetrapods, however, were not the only vertebrates that evolved semi-terrestrial forms and terrestrial adaptations emerged independently in different actinopterygian groups. One of the best known examples are the gobiiform mudskippers (Oxudercinae) that start their life as pelagic larva which metamorphoses to a semiterrestrial form that spends up to 90% of its active life on land. Therefore, mudskippers offer a unique possibility to study functional adaptations demanded by transitions from aquatic to terrestrial life during their ontogeny, as a parallel phenomenon to tetrapod history. Only few postmetamorphic mudskipper species were studied to date in the light of terrestrial adaptations and even less is known on the biology and anatomy of their larvae or the dramatic remodeling during metamorphosis. Here, we propose a project designed to collect larval and adult stages of three poorly studied mudskipper species in the mangrove forests of Qeshm Island, Iran, to study changes across metamorphosis of the respiratory system, the feeding apparatus and the locomotor system.