Taxonomy and phylogeny of the Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata)

The family Archimonocelididae Meixner, 1938 has been revised. The family contains two subfamilies, each comprising two genera: the Archimonocelidinae with Archimonocelis Meixner, 1938 and Meidiama Marcus, 1946, and the Calviriinae subfam. nov. with Asilomaria Karling, 1966 and Calviria gen. nov. with 20, 2, 1, and 3 species, respectively, 13 of which are new to science. The type species of the family is redescribed. Material of all the Archimonocelididae genera has been studied and supplementary remarks are made on some known species. The karyotype of 14 species is described. Archimonocelis has a cosmopolitan distribution while Meidiama is restricted to the South American coast, Calviria to the Mediterranean, and Asilomaria to the Pacific North American coast. The phylogenetic relationships within the family are analysed.