ABSTRACT. – Coronates occur in all oceans from coastal to abyssal waters. In the Mediterranean, three of the six local nausithoid species inhabit marine caves. They have a reduced pelagic life stage in common, which presumably offers them advantages in cave or shallow water habitats, though the mechanisms differ. Within that small number of species, apogamy, parthenogenesis, hermaphrodity and brood care are encountered. In this study, knowledge of habitat and ecology of the Mediterranean Nausithoidae is compiled and the relationships of the species are investigated through a combined approach of morphological and molecular character analysis. Three clades are evidenced. These results are corroborated by studies of the life cycles and observations on the behaviour.