Distribution: Possibly common in the Solitary Island Marine Park. Widespread distribution throughout the Indo-Pacific region including Izu Peninsular in Japan, Philippines, Reunion and Christmas Islands in the Indian Ocean.

Ecological Notes: Found on algae, depth to at least 16 m.

Additional Notes: Easily overlooked due to very small size, these animals have a fragile shell which is completely covered by the mantle. Specimen pictured around 3 mm in length, most records indicate this is approximate maximum size.

References: Australian Museum, Sea Slug Forum. http://www.seaslugforum.net/factsheet/colpthom. Accessed 21/07/18.

Gary Cobb, David Mullins, Nudibranchs Encyclopedia, 2nd Edition, 2015. Publishers Thomas Slone, Masalai Press and Tim Hochgrebe, Underwater Australasia. p.56.