brittle star Ophionotus victoriae

Ophionotus victoriae occurs throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South Sandwich Islands, South Georgia Island, and Bouvet Island in depths from 5 to 1,266 meters [3,4,5,6]. The central disk of O. victoriae is large, flat and circular and can reach a diameter of four centimeters [3]. The arms of O. victoriae are short, flattened, robust, and depressed, taper rapidly, and can reach a length of nine centimeters [3].

Ophionotus victoriae uses its two leading arms in a typical brittle star rowing fashion as it moves on the seafloor searching for food [2].

O. victoriae is variable in color, including brown, red-brown, brick-red, yellowish-pink, bluish grey, grey, white, brownish- violet with darker patches, grey with radial fawn streaks, and brownish-grey; pinkish-fawn banded arms have been observed [3,5].

Maximum age of O. victoriae has been estimated at 22 years [9].

Ophionotus victoriae is an opportunistic predator and also a scavenger and detrital feeder [2]. O. victoriae has a varied diet including seal feces, diatoms, foraminiferans, tunicates/ascidians, sponges, hydroids, bryozoans, polychaetes, bivalve molluscs, crustaceans (euphausiid krill, copepods, amphipods, mysids), sea urchins, and brittle stars [1,2,9]. O. victoriae is a significant predator of brittle stars including its own species (cannibalism), which mostly involves adults eating juveniles [2].

Predators include fish and the larger brittle star Ophiosparte gigas [2,7]. O. victoriae has been observed to respond to contact by the larger brittle star Ophiosparte gigas by quickly fleeing [7,8]. If successful in capture, O. gigas holds the disc of O. victoriae under its own and clips off arms to ingest [7].

1: Polar Biology 3(3):127-139, 1984; 2: Adaptations within Antarctic Ecosystems, Proceedings of the Thrid SCAR Symposium on Antarctic Biology. GA Llano, ed. Washington, DC : Smithsonian Institution, 1977. pp.293-326; 3: 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; 4: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin : P. Parey, 1990; 5: AFJ Madsen. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume 9, Part 3, Ophiuroidea. Adelaide : BANZAR Expedition Committee, 1967; 5: 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; 6: Echinodermata from the Palmer Archipelago, South Shetlands, South Georgia and the Bouvet Island... . JA Grieg. Oslo : I Kommisjon Hos Dybwad, 1929. Scientific Results of the Norwegian Antarctic expeditions, 1927-1928 and 1928-1929 No. 2. Norske Videnskaps-Akademi i Oslo No. 2; 7: Polar Biology 16(5):309-320, 1996; 8: Norbert Wu, personal communication, 1999; 9: Okologie und Populationsdynamik Antarktischer Ophiuroiden (Echinodermata), Ecology and Population Dynamics of Antarctic Ophiuroids (Echinodermata). C Dahm. Berichte zur Polarforschung, Reports on Polar Research 194, 1996

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