Amphibious fishes spend part of their life in terrestrial habitats. The ability to tolerate life on land has evolved independently many times, with more than 200 extant species of amphibious fishes spanning 17 orders now reported. Many adaptations for life out of water have been described in the literature, and adaptive phenotypic plasticity may play an equally important role in promoting favourable matches between the terrestrial habitat and behavioural, physiological, biochemical and morphological characteristics. Amphibious fishes living at the interface of two very different environments must respond to issues relating to buoyancy/gravity, hydration/desiccation, low/high O2 availability, low/high CO2 accumulation and high/low NH3 solubility each time they traverse the air–water interface. Here, we review the literature for examples of plastic traits associated with the response to each of these challenges. Because there is evidence that phenotypic plasticity can facilitate the evolution of fixed traits in general, we summarize the types of investigations needed to more fully determine whether plasticity in extant amphibious fishes can provide indications of the strategies used during the evolution of terrestriality in tetrapods.
The authors declare no competing or financial interests.
Both authors contributed equally to writing and editing the manuscript.
This work was funded by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant to P.A.W. and a Natural Sciences and Engineering Research Council of Canada (NSERC) graduate scholarship to A.J.T.
Supplementary information available online at http://jeb.biologists.org/lookup/doi/10.1242/jeb.126649.supplemental
- Received January 24, 2016.
- Accepted June 29, 2016.
- © 2016. Published by The Company of Biologists Ltd