seastar Macroptychaster accrescens

Macroptychaster accrescens is found throughout Antarctica and the Antarctic Peninsula, South Georgia Island, and Bouvet Island at depths from zero to 655 meters [1,2,4,5]. M. accrescens is uncommonly seen [4]. M. accrescens has been collected at sizes up to 26 centimeters in radius from its center to the tip of an arm [1]. Color has been recorded as orange with darker brown transverse bands across the arms and brown markings on the central disc [1].



Like other seastars in the Astropectinidae, Macroptychaster accrescens lacks sucking discs on its tube feet indicating a preference for soft or muddy environments [1].



Macroptychaster accrescens is a predator of the seastar Odontaster validus, the sea urchin Sterechinus neumayeri, gastropod molluscs, bivalves, and brittle stars [3,4].


Females of Macroptychaster accrescens are presumed to spawn their eggs by broadcasting them into the water where they develop into non- feeding larvae [2]. This pelagic (open ocean) non-feeding larval development is common among McMurdo Sound seastars [2]. Their larvae develop on stored yolk (lecithotrophic) which is probably an adaptation to low food levels [2]. Seastars in temperate and tropical shallow waters typically have feeding larvae [2].

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: Marine Biology 104:41-46, 1990; 3: Ecological Monographs 44(1):105-128, 1974; 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.293-326; 5: 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

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