Revealing the diversity of Parasmittina Osburn, 1952 (Bryozoa, Cheilostomatida) from the Southwest Atlantic: Species complexes, non-native and new species.

Parasmittina is the most representative cheilostome genus of the family Smittinidae, often reported in the fouling non-indigenous marine community. Here, we present a review of Parasmittina species reported in the Southwestern Atlantic including the characterization of one species from Argentina (P. dubitata) and ten from the Brazilian coast: P. abrolhosensis, P. alba, P. bimucronata, P. ligulata comb. nov., P. longirostrata, P. pinctatae, P. serrula, P. simpulata, P. winstonae and the new species Parasmittina falciformis sp. nov. The new species is characterized by a smooth distally primary orifice with 1-2 oral spines, large lyrula, serrated condyles with hooked tips, and two types of avicularia-small and subtriangular and large sublanceolate. This study does not recognize four species previous recorded in Brazil: reports of P. betamorphaea and P. trispinosa are now assigned to P. pinctatae; records of P. munita belong to P. falciformis sp. nov.; and reports of P. spathulata encompass at least two taxa, including P. abrolhosensis and P. simpulata. In this study, five species complexes (P. alba, P. longirostrata, P. serrula, P. simpulata and P. winstonae) were identified and require further investigations. While six species characterized here were first described based on specimens from the Southwestern Atlantic (P. abrolhosensis, P. alba, P. dubitata, P. ligulata comb. nov., P. simpulata and P. falciformis sp. nov.), the remaining species are mainly known from the Indo-Pacific. These taxa are here recognized as exotic (P. longirostrata) and cryptogenic (P. bimucronata, P. pinctatae, P. serrula and P. winstonae) in the studied area. Most of the non-native taxa are widespread along the Brazilian coast, growing on both artificial and natural surfaces, indicating that they are well-established in the area. As non-native bryozoans can negatively influence the environment, affecting human economic activities and beach usage, further studies on the fauna presented here are suggested to determine the origin of these taxa and help prevent bioinvasion events along the SW Atlantic.