Gosliner & Fahey, 2008
Known from Papua New Guinea, Indonesia and southern Japan.
Upper: CASIZ 084868, Ryukyu Islands, Okinawa, 10 mm. Photo: B. Bolland. Lower: CASIZ 084868. Radular morphology. Scale =10 µm. [From Gosliner & Fahey, 2008: Fig12C].
The body is opaque white, with translucent orange oral tentacles and a black [or dark brown] band across the front edge of the head. The gills and rhinophores are translucent clear with orange edgings and the extra-branchial and extra rhinophoral processes are opaque white.
Gosliner & Fahey emphasise the uniqueness of an "elevated hump anterior to the gill" naming the species 'gibbera' from 'the Latin word meaning 'a hump on the back'. To me it looks like the pericardial hump found to varying degrees in all species. In my experience this 'hump' can sometimes be raised and sometimes flattened in an individual so may not be a useful character.
The species has been reported to reach 10 mm in length.
Gosliner, T.M. & Fahey, S.H. (2008) Systematics of Trapania (Mollusca: Nudibranchia: Goniodorididae) with descriptions of 16 new species Systematics and Biodiversity, 6 (1): 53-98
Rudman, W.B., 2008 (March 10) Trapania gibbera Gosliner & Fahey, 2008. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/trapgibb