The Mediterranean specimens of the genus Microporella collected from shallow water habitats during several surveys and cruises undertaken mostly off the Italian coast are revised. As a result of the disentanglement of the M. ciliata complex and the examination of new material, three new species, M. bicollarissp. nov., M. ichnusaesp. nov., and M. pachyspinasp. nov., are described from submarine caves or associated with seagrasses and algae. An additional species Microporella sp. A, distinct by its finely reticulate ascopore, is described but left in open nomenclature owing to the limitations of a single infertile fragment. After examination of all available material, based on their identical zooidal morphology, the genus Diporula is regarded as junior synonym of Microporella and the combination Microporella verrucosa is resurrected as first suggested by Neviani in 1896. Fenestrulina joannae is also reassigned to Microporella. The availability of a large number of colonies of the above-mentioned and other species already well known from the area (i.e., M. appendiculata, M. ciliata, and M. modesta), allowed the assessment of their high intraspecific variability as well as the observation, for the first time, of some morphological characters including ancestrulae, early astogeny, and kenozooids. Finally, M. modesta, in spite of M. ciliata as defined by the neotype selected by Kukliński & Taylor in 2008, appears to be the commonest species in the basin.
