Data from: The many origins of extremophile fishes

Extremophiles survive in environments that are considered uninhabitable
for most living things. The evolution of extremophiles is of great
interest because of how they may have contributed to the assembly of
ecosystems, yet the evolutionary dynamics that drive extremophile
evolution remain obscure. Here, we investigate the evolution of
extremophiles in Zoarcoidea, a lineage of over 300 species of fishes that
have colonized both poles, the deep sea, and hydrothermal vents. We show
that a pulse of habitat invasion occurred across 23 different zoarcoid
lineages within the last eight million years, far after the origin of
their prototypical innovation for surviving in cold water: antifreeze
protein III. Instead, a secondary burst of anatomical, physiological, and
life history traits and a handful of founder-events in extreme ecosystems
appear to have propelled zoarcoid diversification. These results
decentralize the role of prototypical changes to organismal biology in
shaping extremophile radiations and provide a clear example of how a
combination of ancient adaptations and recent contingency shape the
origination of lineages in challenging habitats.