Novel spikey ionocytes are regulated by cortisol in the skin of an amphibious fish

The purpose of this study was to investigate the hypothesis that cortisol is a major regulator of skin ionocyte remodelling during the transition of amphibious fishes from water to land. To test this hypothesis, we measured whole-body cortisol content, skin and gill ionocyte morphometrics, whole-body osmolality and terrestrial jumping performance of the highly amphibious mangrove rivulus (Kryptolebias marmoratus).