Proseriate flatworms are common members of the interstitial benthic fauna worldwide, predominantly occupying marine environments. As minute animals, having relatively few characters useful for cladistic analysis, they have been difficult to present in

Geminate species are a powerful tool for calibrating the molecular clock in marine organisms, and their adoption is mandatory for soft-bodied taxa, which lack fossil records. The first attempt to calibrate the molecular clock in taxa belonging to meiofaunal

Proseriata is a diverse and species-rich taxon of Neoophora (Platyhelminthes). The group is divided into two morphologically well-characterised taxa: Lithophora and Unguiphora. Previous molecular analyses, aimed at ascertaining in-group relationships

Proseriate flatworms are common members of the interstitial benthic fauna worldwide, predominantly occupying marine environments. As minute animals, having relatively few characters useful for cladistic analysis, they have been difficult to present in

The composition of the taxon Proseriata (Platyhelminthes) in the São Sebastião area (S.E. Brazil) is presented and discussed. The area was extensively studied by E. Marcus, who described a large number of species, most of which have not been found thereafter.

Since the opening of the Suez Canal in 1869 the Mediterranean Sea has been affected by a gradually increasing influx of species of Erythraean origin, which significantly modified species composition and ecological interactions of entire communities. Most

Coelogynoporidae (Platyhelminthes) includes comparatively large and slender Proseriata, usually occurring in shallow benthic environments. Coelogynopora Steinböck, 1924 is the most frequently reported genus and the one with the highest species diversity.

Two monocelid species with simplex copulatory bulbs and post-pharyngeal ovaries have been found in E. Australia. One of them presents a combination of characters not found in any of the known genera of the Monocelididae, and the new genus Acanthopseudomonocelis