Resumen:
Bryozoans are aquatic invertebrates, predominantly marine, filter-feeding, sessile and colonial. Cheilostomatida Busk, 1852 is the most successful evolutionary group with more than half of the 8,000 known species. In Cheilostomatida, the family Smittinidae Levinsen, 1909 is considered the most diverse, with more than 300 species widely reported in all seas and oceans, colonizing natural and artificial substrata and with taxa related to bioinvasion events. Among Smittinidae genera, Parasmittina Osburn, 1952 is the most diverse, with 129 described species. In the Atlantic, 30 species are known and 11 of these occur in the Southwestern Atlantic. Most species have never been revised based on current techniques for taxonomy of marine bryozoans and many records have been attributed to species complexes. Thus, the aims of this work were to morphologically characterize species of Parasmittina from the Southwestern Atlantic, including port areas of Brazil; determine the native / cryptogenic / exotic status of each species; reassess the traditional morphological characters used for taxonomy and, finally, present an identification key to the Atlantic species. Eleven species were recognized – one species from Argentina, four species previously described from Brazilian coast (P. abrolhosensis Ramalho, Taylor, Moraes, Moura, Amado–Filho & Bastos, 2018, P. alba Ramalho, Muricy & Taylor, 2011, P. distincta Ramalho, Taylor, Moraes, Moura, Amado–Filho & Bastos, 2018, P. ligulata (Ridley, 1881), P. simpulata Winston, Vieira & Woollacott), five species mainly known from the Indo–Pacific (P. bimucronata (Hincks, 1884), P. longirostrata Liu in Liu, Yin & Ma, 2001, P. pinctatae Liu in Liu, Yin & Ma, 2001, P. serrula Soule & Soule, 1973 and P. winstonae Liu in Liu, Yin & Ma, 2001) and a new species, P. falciformis n. sp. At least three species, P. alba, P. distincta and P. simpulata, are here recognized as part of species complexes that need further investigations. Among five Indo–Pacific species, two are assigned as exotic (P. longirostrata and P. serrula) in SW Atlantic, but other three are assigned as cryptogenic (P. bimucronata, P. pinctatae and P. winstonae). Taxonomic considerations and morphological characterization of other Parasmittina species are provided.
