This appears to be a species of Phyllaplysia. In fact, this one could be simply a darker and more frondose specimen of what we are calling Phyllaplysia sp. e685. It bears some resemblance to some published photos of Phyllaplysia engeli from the Atlantic, and also could be the animal figured in Gosliner et al (2018). as Petalifera sp. It was found on 24 October 2014 by Marissa Brown and photographed here by Jay Lord.
A 25mm specimen was found on algae on the lagoonside of Kwajalein Island at a depth of 6m by Marissa Brown in May, 2015.
Created 22 February 2015
Updated 4 December 2018