Goniobranchus geometricus (Risbec, 1928)

Distribution: 

Uncommon in the Solitary Islands Marine Park. Found in tropical Indo-West Pacific, including Sth Africa, the Maldives, Japan, Okinawa. In Australia known from Western Australia, Queensland, northern New South Wales and Lord Howe Island.

Ecological Notes: 

Found on rocky reef, feeds on sponges including Chelonaplysilla violacea.

Additional Notes: 

Best recognised by the violet/black lines on the mantle and the yellowish/green gills and rhinophores. Grows to around 30 mm.

References: 

Gary Cobb, David Mullins, Nudibranchs Encyclopedia, 2nd Edition, 2015. Publishers Thomas Slone, Masalai Press and Tim Hochgrebe, Underwater Australasia. p.136.

Australian Museum, Sea Slug Forum. http://www.seaslugforum.net/showall/chrogeom. Accessed 07/08/18.