Distribution: Very common in the Solitary Islands Marine Park. Distributed throughout the Indo-West Pacific region. In Australia from Exmouth in Western Australia, across the top and down the east coast south to at least Jervis Bay, southern New South Wales.

Ecological Notes: Found from inter-tidal areas to 20 m in depth, often under coral heads, or on sponges on exposed vertical surfaces. Feeds on sponges including Hyatella intestinalis. 

Additional Notes: Black mantle margins, black border around rhinophore pockets and black rhinophore clubs. Colour may vary from creamy white to pale mustard brown. New South Wales specimens are predominantly white in colour. Grows to 60 mm.

References: Gary Cobb, David Mullins, Nudibranchs Encyclopedia, 2nd Edition, 2015. Publishers Thomas Slone, Masalai Press and Tim Hochgrebe, Underwater Australasia. p.125.

Atlas of Living Australia website at https://bie.ala.org.au/search?q=doriprismatica+atromarginata. Accessed 29/07/18.

Australian Museum, Sea Slug Forum. http://www.seaslugforum.net/find/glosatro. Accessed 29/07/18.