Saint Vincent's Nudibranch

Hypselodoris saintvincentius has a dark blue-black body which is covered in hundreds of small black and white spots. There is typically a creamy-white irregular, lined pattern present on its dorsum. The gills and rhinophores are orange, sometimes outlined in white. This species can reach a total length of at least 40 mm and has been observed feeding on sponges from the genus Dysidea.

This nudibranch is known only from Southern and Southwestern Australia. This species was described from the intertidal zone at Coobowie, west coast of St Vincent Gulf, South Australia 35.044260°S 137.739888°E / -35.044260; 137.739888. It is related to the widespread tropical species Hypselodoris infucata and the similar Australian species Hypselodoris obscura. It has been reported from depths to 12 m and from Western Australia.