Benthic hydroids (Cnidaria: Hydrozoa) from the Bransfield Strait area (Antarctica) collected by Brazilian expeditions, with the description of a new species

A total of 36 species of benthic hydroids, belonging to nine families and 16 genera, were found in the hydroid collection gathered during the Brazilian Antarctic expeditions PROANTAR III and IV. Seven of the species were identified only to generic level. There is a clear dominance of the subclass Leptothecatae with 33 species. By far the most diversified family was the Sertulariidae, with 16 species (44%). Symplectoscyphus with eight species, including Symplectoscyphus magnificus sp. nov., is the most diversified genus. Almost 70% of the species diversity is restricted to just six genera (38%). Sixty-eight percent of the species is Antarctic endemics and 86% is restricted to Antarctic or Antarctic/sub-Antarctic waters. Eudendrium antarcticum and Amphisbetia operculata are recorded for the first time from Antarctic waters.