Sponges (Porifera) from the Ross Sea (Southern Ocean) with taxonomic and molecular re-description of two uncommon species

Porifera are one of the dominant components of the marine benthic communities in the Antarctic Sea (44% of the total species are endemic). Despite these data and the various studies on marine biodiversity, the abundance and diversity of sponges on shallow Antarctic reefs and in the deep sea are likely significantly underestimated. In this context, our work deals with the description of Antarctic sponges inhabiting Tethys Bay (Ross Sea). A total of 46 sponge specimens were collected at different depths during three separate Italian Antarctic Expeditions and identified into 15 species within the Demospongiae and Hexactinellida classes. More importantly, we report on finding two species, i.e. Haliclona scotti and Mycale (Aegogropila) denticulata, for the first time after 114 and 16 years, respectively, from their original description. More details are also given on their taxonomic re-description and molecular characterization.