Acotylean 21
top: Scott Johnson, small cave near Makua, O'ahu, Size: 35 mm.
middle: Rebecca Bicker, Molokini, Maui, 30-40 ft. (at night).
bottom: Adrienne Peck, Kawaihae, Hawai'i. 20 ft. (at night)

ID from Newman & Cannon CD. Body is fleshy with a few marginal ruffles; it has elongate black head tentacles. Known only from Hawai`i from several photographs by Scott Johnson from the 1980s and one by Rebecca Bicker taken in 2020. Might belong to family Planoceridae. More photos of this rare and striking worm would be welcome.

UPDATE June 2023: Adrienne Peck found another in June, 2023 (photo 3). She writes: "Found Night Diving in Kawaihae on 6.2.23 in 20’ water on a coral head. Approx. 25mm."

UPDATE July 2024: We had thought this worm occurred only in Hawaii, but Erik Peeters photographed what appears to the same worm at Umm Usk near Hurghada, Egypt, in the Red Sea, a very long way from Hawaii! See photo 4.

BACK to longitudinal stripes