See text Dimarcusidae is a family of triclads found mostly in freshwater habitats of caves, although at least one species, Rhodax evelinae, occurs in surface waters.

[2] The family Dimarcusidae was erected in 1972 by Mitchell and Kawakatsu to include a new species, Dimarcus villalobosi.

However, the same species had been briefly described by Benazzi in the same year as Opisthobursa mexicana and this name had priority, with Dimarcus villalobosi becoming a junior synonym.

As a result, the family is called Dimarcusidae despite the absence of a valid genus Dimarcus.

[2] Recent molecular studies, however, suggest that Cavernicola is the sister group of Maricola, thus being more closely related to marine than to freshwater triclads.