Gaining the ability to feed in terrestrial environment allows fish to exploit novel food resources. However, the difference in physical characteristics between air and water, i.e., much lower density and viscosity of the former, would dictate a change in feeding mechanisms: suction feeding, the dominant feeding mode of aquatic vertebrates, hardly works in the air. There are some extant amphibious fishes that feed on land. However, most published studies have dealt with the feeding mechanisms of carnivorous amphibious fishes that prey on relatively large food items, and little is known about herbivorous fishes grazing on land. In this study, we investigated the morphology of the feeding apparatus of Boleophthalmus pectinirostris, a herbivorous mudskipper, to understand how feeding apparatus is modified for grazing on land. Dentition, and the skeletal and muscular systems of the branchial basket were examined through macroscopic and microscopic dissection, scanning electron microscopy, and micro-computed topography scanning. The results show that the feeding apparatus of the fish has been modified presumably to transport diatom cells from the mudflat surface to the digestive tract with minimum admixture of mud particles. The modifications include horizontal orientation of the lower jaw teeth, horizontally aligned, high-density gill rakers on the third (only on the posterior raw) and fourth (both rows) gill arches, large pharyngeal plates bearing numerous fine teeth, and the musculoskeletal system of the branchial basket.

中文翻译：

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草食性弹涂鱼 Booleophthalmus pectinirostris (Linnaeus, 1758) 摄食装置的形态学

获得在陆地环境中觅食的能力使鱼类能够开发新的食物资源。然而，空气和水之间物理特性的差异，即前者的密度和粘度要低得多，这将决定摄食机制的变化：吸食，水生脊椎动物的主要摄食方式，几乎不能在空气中工作。有一些现存的两栖鱼类以陆地为食。然而，大多数已发表的研究都涉及捕食相对较大食物的肉食性两栖鱼类的摄食机制，而对在陆地上放牧的食草鱼类知之甚少。在这项研究中，我们调查了草食性弹涂鱼 Boleophthalmus pectinirostris 的摄食装置的形态，以了解如何修改摄食装置以在陆地上放牧。牙列，并通过宏观和微观解剖、扫描电子显微镜和微计算机地形扫描检查鳃篮的骨骼和肌肉系统。结果表明，鱼的摄食装置可能已经过改进，可以将硅藻细胞从泥滩表面运送到消化道，同时泥颗粒的混合量最少。修改包括下颌牙齿的水平方向，水平对齐的高密度鳃耙在第三（仅在后生）和第四（两排）鳃弓上，带有许多细牙的大咽板，以及肌肉骨骼系统鳃篮的。和微计算机地形扫描。结果表明，鱼的摄食装置可能已经过改进，可以将硅藻细胞从泥滩表面运送到消化道，同时泥颗粒的混合量最少。修改包括下颌牙齿的水平方向，水平对齐的高密度鳃耙在第三（仅在后生）和第四（两排）鳃弓上，带有许多细牙的大咽板，以及肌肉骨骼系统鳃篮的。和微计算机地形扫描。结果表明，鱼的摄食装置可能已经过改进，可以将硅藻细胞从泥滩表面运送到消化道，同时泥颗粒的混合量最少。修改包括下颌牙齿的水平方向，水平对齐的高密度鳃耙在第三（仅在后生）和第四（两排）鳃弓上，带有许多细牙的大咽板，以及肌肉骨骼系统鳃篮的。