Click the thumbnail photos to enhance!
it is as Pseudobiceros sp. 1 at page 102 in
Gosliner, T.M., Behrens, D.W. & Williams, G.C. (1997) Coral Reef Animals of the Indo-Pacific. 314pp.
Monterey, California: Sea Challengers.
This species is either pretty variable, as the 12 (as of 26 January 2015) pictures at NUDIPIXEL are demonstrating, or some of them are misidentified.
Let me quote Marcela Bolanos at LifeDesks:
"External anatomy: Oval body slightly tapered posteriorly, with very ruffled margins. The background varies from bright olive green to dark brown or black with a narrow longitudinal median white line, bordered by darker pigment. There are three marginal bands, a wide inner black, then olive green and white at the edge. The ventral side is light green or brown with a white rim. The pseudotentacles are square and ruffled with white tips and a white triangle is formed between them."
I like to repeat: The ID is tentative, because the above pictures do not fit the description, just as most of the pictures at NUDIPIXEL! Almost all of the above specimens are lacking the submarginal olive green band, only the specimen #7 fits the description.
How to cite:
Köhler, E. (2017), published 18 July 2017, Pseudobiceros flowersi Newman & Cannon 1997
available from https://www.Philippine-Sea-Slugs.com/Look-alike/Platyhelminthes/Pseudobiceros_flowersi/Select.htm