Structure and function of sensory organs

Mudskippers have many morphological adaptations that enable them to cope with the different conditions encountered in and between aquatic and terrestrial habitats. This is challenging especially for fishes with a body plan suitable for the aquatic medium. In addition to essential processes such as osmoregulation, excretion, respiration, thermal balance, and locomotion, basic functioning senses such as photoreception, chemoreception, and mechanoreception must now accommodate both habitats (Sayer 2005).At a position usually directly on or close to the body surface, receptor cells can readily receive impulses from the surrounding environment but at the same time, expose these receptors to external conditions. The adaptations to these demanding environments have made mudskippers a frequently studied fish group and make them possible extant models for the Paleozoic evolution of vertebrate transition from water to land (Graham and Lee 2004).