The monotypical ameronothrid genera Alaskozetes, Aquanothrus, Podacarus, Pseitdantarcticola and Antarcticola (z species) are restricted to wet and cold, polar and alpine (mountainous) terrestrial habitats. The polytypical ameronothrid genera Halozetes and Ameronothrus comprise transitional species living in terrestrial environments and in the marine littoral. Within several species of these genera ecological specializations have been established regarding adaptations to littoral substrates, submersion and salinity. A hypothesis of the evolution of the Ameronothridae was suggested. From scatterd relict terrestrial biotops, ameronothrids invaded aquatic habitats including mountainous freshwaters and polar coastlines. Terrestrial spedes were restricted and therefore unable to leave the relict habitats. The coastal species spread themselves throughout various littoral zones along continental shores.