Janolus flavoanulatus Pola & Gosliner, 2019

サーシャコヤナギウミウシ Janolus flavoanulatus
Photographed by
Nicholas Chay
Tulamben, Pulau Bali, Indonesia
Water temperature


Living specimens reaching 50 mm in length (Gosliner et al., 2008, 2015). Body broadest anteriorly, tapering to posterior end of foot extending well beyond notum. Rhinophores elongate with about 20–25 complete or incomplete transverse lamellae. Well-developed convoluted caruncle present between rhinophores (Figure 6a–c). Two eyes appearing as small black dots, appearing by transparency just behind rhinophores. Large, swollen cardiac area located near middle of notum. Pair of short and digitiform oral tentacles extending from either side of head. Cerata elongate, globose centrally, ending with acutely pointed apex. Most of cerata are covered with many prominent tubercles near middle. Cerata arranged in 8–12 closely-packed longitudinal rows with 4–5 cerata per row on each side which are irregularly arranged. Digestive gland inserting into most cerata at base, splitting into numerous branches, and terminating at globose portion of cerata. Anteriormost cerata often lacking extensions of digestive gland. Anus located mid-dorsally near posterior end of notum on elevated papilla. Anal glands absent. Gonopore located on right side in middle of body.


Indian and western Pacific oceans (Gosliner et al., 2015). This species has been found in the Philippines (Gosliner et al., 2008; present study), Papua New Guinea (Coleman, 2008), Japan, Solomon Islands, Red Sea, Indonesia, Vanuatu (Gosliner et al., 2008), Indonesia (Debelius & Kuiter, 2007) and perhaps Australia (www. nudipixel.net).


The specific name, flavoanulatus refers to the yellow subapical ring of the cerata (from the Latin words flavus, yellow and anulatus, ringed).