The morphological characters of the genera until now assigned to the families Ameronothridae, Podacaridae and Aquanothridae were critically surveyed. Groups of genera did not differ by decided gaps of morphological characters, and so these groups should not be regarded as monophyletic groups of the rank of families. The unification of the genera Ameronothrus, Aquanothnts, Podacarus, Alaskozetes, Halozetes, Antarcticola and Pseztdantarcticola in the single family Ameronothridae is proposed. A revision of Alaskozetes would probably result in its synonymy with Podacarus.