A new carnivorous shallow-water sponge from McMurdo Sound, Antarctica (Porifera, Poecilosclerida)

A new shallow-water representative of the carnviorous sponge genus Asbestopluma is described from the southernmost Antarctic region of McMurdo Sound. Asbestopluma (Asbestopluma) vaceleti n.sp. is a white, thin, sparingly branched sponge fringed by filaments along its entire length, with a slight thickening at the top of the branches. It was collected at 30 m depth by SCUBA divers from under densely populated overhangs of rocky substrata. The new species stands out among Antarctic Asbestopluma by the possession of forceps microscleres, a feature shared with several species from Arctic-Boreal waters (bathyal to deep-sea) and one from the Kermadec Trench (deep sea), but not previously reported from Antarctic species. A unique trait of the new species distinguishing it from all forceps-bearing Asbestopluma is a second category of reduced anisochelae. The new species is most similar to A. hypogea, a shallow-water cave species from the Mediterranean, which differs in having a smooth stalk and a filament-bearing ovoid body. A comparison is made with descriptions of Antarctic Asbestopluma species and all species possessing forceps microscleres.