Fish have evolved to live on land multiple times, suggesting that the crucial transition from water to land during the evolution of terrestrial life may not have been unusual.
Terry Ord and Georgina Cooke at the University of New South Wales in Kensington, Australia, looked at data on the behaviour and ecology of living fish and identified 33 different families that include amphibious species, some of which seldom leave the land. In one family, the blenny fish (Blenniidae), amphibious lifestyles evolved 3–7 times. The duo observed one primarily aquatic species of blenny (Praealticus labrovittas) emerging onto land on warm days on the western Pacific island of Guam.
The ability to survive on land could help fish to cope with the low oxygen levels of warm seawater, and prevent them getting stuck in tidal pools, the authors propose.
Evolution http://doi.org/bjzq (2016)