brittle star Ophiosparte gigas

Ophiosparte gigas is found throughout Antarctica and the Antarctic Peninsula at depths from 8 to 1,200 meters [1,2,3,4,5]. The disc of O. gigas is thick, mucus-covered, convex, and up to seven centimeters in diameter; its large disc relative to the arms makes it easy to recognize [1,4,5]. The arms of O. gigas have spatulate arm spines, conical tube feet, and are up to seventeen centimeters long [1,4,5].



Ophiosparte gigas lives on soft substrate; its movement is made more efficient by its paddle-like arm spines and stilt-like tube feet [1].

O. gigas is colored pink, deep pink, pinkish orange, deep reddish, purplish brown, or brick red [1,4,5].

Ophiosparte gigas is an active benthic predator on large prey, primarily brittle stars (including its own species, Ophiurolepis gelida, Ophionotus victoriae, Ophiacantha sp., Ophiocten sp.), bivalves (including Adamussium colbecki, Yoldia eightsi, Yoldiella sabrina), polychaete worms, crustaceans, and sponges [2,5]. O. gigas also preys on diatoms, algae, foraminifera, hydroids, nematodes, gastropods (including Nacella concinna), sea spiders, ostracods, mysids, amphipods, isopods, euphausiids (including Euphausia crystallorophias, Euphausia superba), the shrimp Chorismus antarcticus, bryozoans, cheilostomes, the crinoid Promachocrinus kerguelensis, seastars, and sea urchins (including Sterechinus neumayeri) [5]. The brittle star Ophionotus victoriae has been observed to respond to O. gigas contact by quickly fleeing [5,6]. If successful in capture, O. gigas holds the disc of Ophionotus victoriae under its own and clips off arms to ingest [5]. O. gigas is also a scavenger [2,5].

1: 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; 2: 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; 3: Jim Mastro, personal communication, 1999 [10 meters at Explorer's Cove in New Harbor]; 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: Polar Biology 16(5):309-320, 1996; 6: Norbert Wu, personal communication, 1999

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