Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743, Jena, Germany
Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.
J Exp Biol. 2018 Apr 25;221(Pt 8):jeb154427. doi: 10.1242/jeb.154427.
Transitions to terrestrial environments confront ancestrally aquatic animals with several mechanical and physiological problems owing to the different physical properties of water and air. As aquatic feeders generally make use of flows of water relative to the head to capture, transport and swallow food, it follows that morphological and behavioral changes were inevitably needed for the aquatic animals to successfully perform these functions on land. Here, we summarize the mechanical requirements of successful aquatic-to-terrestrial transitions in food capture, transport and swallowing by vertebrates and review how different taxa managed to fulfill these requirements. Amphibious ray-finned fishes show a variety of strategies to stably lift the anterior trunk, as well as to grab ground-based food with their jaws. However, they still need to return to the water for the intra-oral transport and swallowing process. Using the same mechanical perspective, the potential capabilities of some of the earliest tetrapods to perform terrestrial feeding are evaluated. Within tetrapods, the appearance of a mobile neck and a muscular and movable tongue can safely be regarded as key factors in the colonization of land away from amphibious habitats. Comparative studies on taxa including salamanders, which change from aquatic feeders as larvae to terrestrial feeders as adults, illustrate remodeling patterns in the hyobranchial system that can be linked to its drastic change in function during feeding. Yet, the precise evolutionary history in form and function of the hyolingual system leading to the origin(s) of a muscular and adhesive tongue remains unknown.
从水生环境向陆地环境的转变使水生动物面临着几个机械和生理问题，这是由于水和空气的物理性质不同。由于水生动物通常利用相对于头部的水流来捕捉、运输和吞咽食物，因此，水生动物为了在陆地上成功完成这些功能，必然需要进行形态和行为上的改变。在这里，我们总结了脊椎动物在成功进行水生到陆生的食物捕捉、运输和吞咽过程中的机械要求，并回顾了不同类群是如何满足这些要求的。两栖的硬骨鱼类展示了多种稳定提起前躯的策略，以及用下颚抓取地面食物的策略。然而，它们仍然需要回到水中进行口腔内的运输和吞咽过程。从同样的机械角度来看，一些最早的四足动物在进行陆地进食方面的潜在能力也得到了评估。在四足动物中，可移动的颈部和具有肌肉和可移动的舌头的出现可以被安全地视为远离两栖栖息地而在陆地上定居的关键因素。对包括蝾螈在内的各种分类群的比较研究表明，在咽弓系统中存在着重塑模式，这与它们在进食过程中功能的急剧变化有关。然而，导致肌肉发达和粘性舌头起源的舌腭系统的形态和功能的精确进化历史仍然未知。
