platyctenean ctenophore Lyrocteis flavopallidus

Lyrocteis flavopallidus has been found in Antarctica and South Shetland Islands at depths from 36 to 761+ meters [1,2,3,4,6]. Video transects of the Ross Sea observed L. flavopallidus rarely and principally on shallow banks having a mean depth of 377 meters [5].

Lyrocteis flavopallidus is saddle-shaped, pale straw-yellow in color, and has been collected at sizes up to eleven centimeters high [1,4]. L. flavopallidus has been found perched on sponges (Rosella racovitzae, Tetilla leptoderma) or elevated surfaces, is soft and fragile, and secretes mucus when disturbed [1].

[Photograph courtesy of Dirk Schories]

Lyrocteis flavopallidus sits with its oral end down and usually moves less than two to three centimeters over a long period of time [1]. One L. flavopallidus moved 35 centimeters in 24 hours onto a marker rod like this, probably to gain a higher perch for better filter feeding [1]. L. flavopallidus has a skirt on the base of its trunk around the oral area which it uses to glide forward [1].


Lyrocteis flavopallidus has adhesive, retractile tentacles (branched on one side) which extend to lengths up to seventy centimeters [1]. Food is caught by the sticky tentacles and transferred to the mouth [1]. The body and arms of L. flavopallidus usually bend in the same direction of current flow with the tentacles streaming out [1]. L. flavopallidus adults do not have the characteristic ctene (comb) rows seen in many other ctenophores [1].

1: Canadian Journal of Zoology 50:47-53, 1972; 2: Annales de l'Institut Oceanographique 73(2):139-158, 1997; 3: Polar Biology 20(4):229-247, 1998; 4: Guide to the Ctenophores of the Southern Ocean and Adjacent Waters. D O'Sullivan. ANARE Research Notes 36. Kingston, Australia : Australia Antarctic Division, 1986; 5: Biogeochemistry of the Ross Sea. GR DiTullio & RB Dunbar, editors. Antarctic Research Series Volume 78. Washington, D.C.: American Geophysical Union, 2003. pp.327-354; 6: Guia Marina Antarctica. D Schories. www.guiamarina.com

Text ©Peter Brueggeman. Photographs ©Paul Dayton & Dirk Schories. Photographs may not be used in any form without the express written permission of Paul Dayton & Dirk Schories.