Click the thumbnail photos to enhance!
Let me quote the description in IPN at page 337: "Body greenish brown with dense, prominent tubercles covering the notum. Tubercles outlined basally with dark brown pigment. Opaque white covers some of the tubercles. Velar tentacles are simple. Secondary gills highly ramified."
The gills seem to be very variable in colour, ranging from translucent white to greenish-brown, and to turquoise.
The identification of the specimens #1 - #3 was confirmed by David W. Behrens, thanks!
This picture shows a specimen upon its violet egg mass
Let me quote Bill Rudman:"This group of tritoniids needs more work. At the moment it is hard to say how many species there are in the tropical Indo-West Pacific. It is possible that species vary in colour depending on the colour of the soft-corals they are feeding on but basically we don't know."
Pretty similar are:
Marionia sp. 08, I am not convinced that they are distinct species, I will keep them seperate for now.
Marionia sp. 10, which differs by a pale tan body, and lacks prominent tubercles.
Marionia sp. 15 which differs by a pale tan body with a whitish reticulate pattern.
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers Natural History Books.
Gig Harbor, Washington. 426 pp.
How to cite:
Köhler, E. (2016), published 24 December 2016, Marionia arborescens Bergh, 1890
available from https://www.Philippine-Sea-Slugs.com/Nudibranchia/Dexiarchia/Marionia_arborescens.htm