Anoxycalyx (Scolymastra) joubini (Topsent, 1916)

provided by British Antarctic Survey

Description

Anoxycalyx joubini, often referred to as a volcano sponge, is a large vase or pear shaped sponge occurring as singletons or small groups. Some are tall and wide enough for a person to fit inside. The pores in the walls are quite obvious, especially inside it. Such pores can harbour a wide range of other animals: looking inside can reveal many arthropods particularly amphipods but also sometimes pycnogonans and shrimps as well as many types of worm. This species grows very slowly and specimens may be very old. These sponges are a good location to see the yellow seastar Acodontaster conspicuous, which may even occur in clusters over it.