seastar Notasterias armata

Notasterias armata is found throughout Antarctica and the Antarctic Peninsula and South Shetland Islands from 15 to 752 meters depth [1,2,7]. The disc of N. armata is small and its arms taper to blunt tips [2]. N. armata has been collected at sizes up to thirteen centimeters in radius from its center to the tip of an arm [2,3]. The color of N. armata can be orange, creamy white, red, and mottled red with creamy areas [2,3].



Here Notasterias armata is attacking the Antarctic scallop Adamussium colbecki.

The diet of N. armata includes the the Antarctic scallop A. colbecki as well as the bivalve Limatula hodgsoni [1,6].


Here's a closer view of Notasterias armata.

N. armata broods its young in a brooding posture with a strongly convex disc and supporting itself on bent arms [2]. Ripe females have been observed from August to February [5]. Brood protection occurs quite commonly among Antarctic marine invertebrates [4]. Brood protection helps larvae avoid the stresses of the environment and predation [4]. Brooding helps larvae avoid the dangers of being eaten if the larvae were planktonic in a strong seasonal planktonic cycle as seen in Antarctic waters [4].

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 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 3: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin : P. Parey, 1990; 4: 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.135-157; 5: Marine Biology 104: 41-46, 1990; 6: Ecology of the Circumpolar Antarctic Scallop, Adamussium colbecki (Smith, 1902). Paul Arthur Berkman. Ph. D. Dissertation, University of Rhode Island, 1988; 7: Mitteilungen aus dem Hamburgischen Zoologischen Museum und Institut 89:239- 259, 1992

Text ©Peter Brueggeman. Photographs ©Norbert Wu & Canadian Museum of Nature (Kathleen Conlan). Photographs may not be used in any form without the express written permission of Norbert Wu and Canadian Museum of Nature (Kathleen Conlan). Norbert Wu no longer grants permission for uncompensated use of his photos under any circumstances whatsoever; want more info?