volcano sponge Anoxycalyx (Scolymastra) joubini

Anoxycalyx (Scolymastra) joubini is found throughout Antarctica and South Shetland Islands at depths from 45 to 441 meters [1,3]. Anoxycalyx (Scolymastra) joubini can be up to two meters high and 1.4 meters in diameter but is usually smaller and often pear-shaped [3,5]. Color can be pale yellow or white [3,4]. The large excurrent opening (oscule) may be fringed by long spicules [3].

Anoxycalyx (Scolymastra) joubini appears to be slow-growing; there was no measurable growth for two sponges for ten years, one for nine years, and four sponges for three years [5]. One sponge increased in diameter from 75 to 77 centimeters in ten years; another increased in diameter from 34 to 37 centimeters in three years [5]. An extract from A. joubini has antibacterial, antifungal, and antiyeast activity which indicates promise for drug development [2].

A common predator of Anoxycalyx (Scolymastra) joubini is the seastar Acodontaster conspicuus (shown at left on A. joubini) [4,5]. Acodontaster conspicuus leaves deep grooves on the surface of the sponge [4,5]. Observations suggest that a single Acodontaster conspicuus does not stay long on A. joubini but several accumulate, do not leave, and consume enough of the sponge to kill it [5]. Another A. joubini predator is the dorid nudibranch Doris kerguelenensis whose predation leaves circular scars and holes [5].

The diver might find fish sheltering within Anoxycalyx (Scolymastra) joubini. Many organisms can be found within A. joubini including amphipods, isopods, and polychaete worms [6].

Taxonomic Note: In 2002 it was synomized to the genus Anoxycalyx with concepts retained in the subgenus Scolymastra, but the subgenera of Anoxycalyx may be combined in the future [7].

1: Hooper, JNA & Wiedenmayer, F. Porifera. IN: Zoological Catalogue of Australia. Volume 12. Wells, A, ed. Melbourne : CSIRO Australia, 1994; 2: Antarctic Science 4(2):179-183, 1992; 3: Antarctic Hexactinellida. Dagmar Barthel & Ole S. Tendal. Champaign, Ill. : Koeltz Scientific Books, 1994. Theses Zoologicae, Volume 23. Synopses of the Antarctic Benthos, Volume 6; 4: Ecological Monographs 44(1):105-128, 1974; 5: Biologie des Spongiaires, Sponge Biology. C Levi and N Boury-Esnault, eds. Colloques Internationaux du Centre National de la Recherche Scientifique Number 291. Paris : Centre National de la Recherche Scientifique, 1979. pp.271-282; 6: Associated Fauna of Selected Sponges (Hexactinellida and Demospongiae) from the Weddell Sea, Antarctica. Kunzmann, K. Berichte zur Polarforschung / Reports on Polar Research 210, 1996; 7: Systema Porifera. JNA Hooper and RWM Van Soest. New York: Kluwer, 2002

Text ©Peter Brueggeman. All photographs © Norbert Wu. Photographs may not be used in any form without the express written permission of Norbert Wu. Norbert Wu no longer grants permission for uncompensated use of his photos under any circumstances whatsoever; want more info?