seastar Psilaster charcoti

Psilaster charcoti is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South Orkney Islands, South Sandwich Islands, South Georgia Island, Bouvet Island, and Macquarie Island from 10 to 3,900 meters depth [1,3,4,5,6]. The dorsal surface of P. charcoti is slightly convex; its arms are wide at the base, have steeply vertical sides, and taper evenly from its broad disc to the sharp arm tips [1,4]. P. charcoti has a central anus, long slender tube feet without distinct sucking discs, and its oval madreporite is between arms and nearer the edge than center [1]. The lack of distinct suckers on the tube feet of P. charcoti indicates a preference for a muddy environment [1]. P. charcoti has been collected at sizes up to sixteen centimeters in radius from its center to the tip of an arm [2,4]. The color of P. charcoti is reddish brown, brown yellow, light tan, bright or pale pink, purplish, or violet and its edges may be lighter; young may be pale yellow [1,4,6].

Psilaster charcoti has been collected with its stomach filled with mud, fecal material, the remains of a polychaete worm, and, pieces of a colonial ascidian; it has also been captured with hooks baited with fish chunks [3]. Thus P. charcoti is an active predator on some invertebrates and ingests mud to eat organisms therein; it also scavenges on feces and dead organisms [3]. P. charcoti is noted as being slimy, suggesting ciliary-mucus feeding [3].

1: 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; 2: Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie 63:175-184, 1993; 3: 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; 4: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 5: Tethys 6(3):631-653, 1974; 6: Memoirs of Museum Victoria 57(2):167-223, 1998

Text ©Peter Brueggeman. Photograph © Jim Mastro. Photographs may not be used in any form without the express written permission of Jim Mastro.