South Orkney Islands: a poorly sponge-studied region of the White Continent. Results of Argentinean Antarctic Cruises 2012 and 2014

CRISTOBO J.; RÍOS P.; LAURA SCHEJTER

Galway

Conferencia; 10th. World Sponge COnference; 2017

The South Orkney Islands are among the poorest studied areas regarding sponge fauna in Antarctica. In 1986 the Spanish Expedition Antártida 8611 sampled 6 stations in the region, but the sponge data remains unpublished. Sará et al. (1992) reviewed the demosponge fauna of Antarctica and the South Orkney region had recorded only 8 species. Lately, van Soest et al. (2012) mentioned 9 species for the same region. A recent search through OBIS database for this marine Ecoregion recorded about 300 unpublished records, most of them not identified to species level (R. Downey, pers. comm.). These numbers highlight a gap in the knowledge of the South Orkney fauna. During two Argentinean Antarctic Research Cruises (2012 and 2014) onboard R/V ?Puerto Deseado? 17 sites in the mentioned region were sampled. Sponge samples were separated from trawl catches and constituted in 4 sites the main component of the catch in terms of relative biomass. Sponge richness per site varied between 1 and 20 (based on morphotypes, and including hexactinellids). A list of the recorded Demospongiae (mainly Poecilosclerida) comprised a total of 32 taxa of which 1 is a new species (Coelosphaera (Coelosphaera) sp. nov.) and at least 21 are new records for Orkney islands. Orders Spirophorida, Astrophorida, some species of Haplosclerida and Class Hexactinellida were also recorded and are still in study. The best represented species in the sampled stations were: Iophon unicorne, I. gaussi, Lissodendoryx (Ectyodoryx) ramilobosa, Tedania (Tedaniopsis) tantula. Other new records for the area were: Raspailia (Hymeraphiopsis) irregularis, Myxilla (Burtonanchora) lissostyla, M. (Myxilla) mollis, Mycale tylotornota, M. fibrosa, Clathria (Axosuberites) cf. nidificata, Artemisina apollinis, Crella (Pytheas) crassa, Isodictya cf. kerguelenensis, I. verrucosa, I. lankesteri, Microxina charcoti, M. benedeni, Inflatella belli, Calyx cf. arcuarius, Myxodoryx hanitschi, Axinella antarctica, Haliclona (Gellius) sp., and Haliclona sp. Except for Mycale (Oxymycale) acerata (also recorded), Iophon unicorne and Calyx arcuarius the other species have never been formally recorded in South Orkney Islands.