New records of demosponges (Porifera) from the South Orkney Islands (Antarctica) with a checklist for the region.

The South Orkney Islands (SOI) is a poorly studied Antarctic archipelago located in the Scotia Arc. In this study, we added 25 Demospongiae species to the SOI known sponge richness, which was previously represented by only 16 species. Of these, 22 species represent new records for SOI region, although they were previously recorded from other Antarctic sectors.

Checklist of Benthic Cnidaria in the SW Atlantic Ocean (54ºS-56ºS).

In this study we provide an updated checklist of benthic Cnidaria from SW Atlantic Ocean that comprised the Marine Protected Areas Namuncurá I and II, located at Burdwood bank, and other neighbouring locations. A total of 88 taxa was recorded: 36 hydrozoans and 52 anthozoans from which 32 were octocorals, 10 scleractinian corals, 8 sea anemones and 2 zoanthids. Burdwood bank presented the highest richness considering that 87% of the recorded species inhabit this plateau or its slope.

Avoiding being dragged away: finding egg cases of Schroederichthys bivius (Chondrichthyes: Scyliorhinidae) associated with benthic invertebrates.

Egg cases of the narrowmouthed catshark Schroederichthys bivius were recorded entangled with sponges, corals and tubeworms at different sites in the south-west Atlantic Ocean. This work sheds light on the importance of benthic invertebrates in the life cycle of oviparous chondrichthyan species.

Isolation and Antifouling Activity of Azulene Derivatives from the Antarctic Gorgonian Acanthogorgia laxa.

Three azulenoid sesquiterpenes (1 - 3) were isolated from the Antarctic gorgonian Acanthogorgia laxa collected by bottom trawls at -343 m. Besides linderazulene (1), and the known ketolactone 2, a new brominated C linderazulene derivative (3) was also identified. This compound has an extra carbon atom at C(7) of the linderazulene framework.

Isolation of acetylated bile acids from the sponge Siphonochalina fortis and DNA damage evaluation by the comet assay.

From the organic extracts of the sponge Siphonochalina fortis, collected at Bahía Bustamante, Chubut, Argentina, three major compounds were isolated and identified as deoxycholic acid 3, 12-diacetate (1), cholic acid 3, 7, 12-triacetate (2) and cholic acid, 3, 7, 12-triacetate. (3). This is the first report of acetylated bile acids in sponges and the first isolation of compound 3 as a natural product.

Dolabellane Diterpenoids from the South Atlantic Gorgonian Convexella magelhaenica.

Two new dolabellane diterpenoids (1 and 2) were isolated from a small sample of the deep water gorgonian octocoral Convexella magelhaenica collected as a nontarget by-catch by dredging (-93 m) in commercial Patagonian scallop fishing grounds in the South Atlantic. The structures of the new compounds, which are major metabolites in the extract, were established by spectroscopic techniques and chemical transformations. Both compounds were cytotoxic against a human pancreatic adenocarcinoma cell line at micromolar concentrations.