Carnivorous sponges (Porifera, Demospongiae, Poecilosclerida, Cladorhizidae) from the Drake Passage (Southern Ocean) with a description of eight new species and a review of the family Cladorhizidae in the Southern Ocean

This study reviews the taxonomy and biogeography of carnivorous sponges (family Cladorhizidae) in the Southern Ocean. Specimens were collected from seamounts in the Drake Passage by dredging and trawling and biogeographical information from other sources was compiled and reviewed. Eight new species of carnivorous sponges are described: Abyssocladia leverhulmei sp. nov., Asbestopluma (Asbestopluma) sarsensis sp. nov., A. (A.) gemmae sp. nov., A. (A.) rhaphidiophorus sp. nov., A. (Helophloeina) keraia sp. nov., Chondrocladia (Chondrocladia) saffronae sp. nov., Cladorhiza scanlonae sp. nov., and Lycopodina drakensis sp. nov. Specimens of three previously described species, L. callithrix, L. calyx, and A. (A.) bitrichela, were also found. These new records increase the number of known carnivorous sponge species in the Southern Ocean by more than a third. We demonstrate that the Cladorhizidae are the second most species-rich family of Demospongiae in the southern ocean and are highly endemic, with 70% of species found only in this region. Southern Ocean species represent close to 20% of all known carnivorous sponges. This study highlights the importance of seamount and bathyal benthic habitats for supporting the rich and endemic carnivorous sponge fauna of the Southern Ocean.