brittle star Ophiacantha antarctica

Ophiacantha antarctica is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South Georgia Island, and the Antarctic Ocean south of the polar circle in depths from 20 to 3,398 meters [1,2,4,5,6]. The color of O. antarctica is variable including disc colors of bluish-grey, grey, reddish, and purple and arm colors of orange, straw, and pinkish [2,3].



The pentagonal central disc of O. antarctica is up to 1.3 centimeters in diameter with indentations on the sides between arms [2,4]. The slender, fragile arms of O. antarctica are up to nine centimeters in length [2,4].

Ophiacantha antarctica is an active forager and its diet includes diatoms, foraminifera, copepods, and other microzooplankton [1]. O. antarctica is generally found up on the substrate (rocks, sponges, sessile cnidarians, etc.) [1,3]. Its flexible arms, long erect and thin arm spines, and climbing ability suggests that it feeds by manipulating its arms and arm spines to capture its food on or near the bottom [1].



Ophiacantha antarctica is the most abundant and widely distributed echinoderm in the Ross Sea, playing an important role in the benthic biological balance [2].

1: Adaptations within Antarctic Ecosystems : Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington : Smithsonian Institution ; Houston, Tex. : distributed by Gulf Pub. Co., 1977. pp.293-326; 2: The Fauna of the Ross Sea, Part 1, Ophiuroidea. HB Fell. New Zealand Department of Scientific and Industrial Research Bulletin 142, New Zealand Oceanographic Institute Memoir 18, 1961; 3: John Dearborn, personal communication, 1999; 4: Equinodermos Antarticos. III. Ofiuroideos. 1. Ofiuroidoes del Extremo Norte de la Peninsula Antartica. I Bernasconi and MM D'Agostino. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Hidrobiologia 4(2):81-133 and plates, 1974; 5: Tethys 6(3):631-653, 1974; 6: Polar Biology 26(11):691-699, 2003

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