Hypselodoris saintvincentius

Hypselodoris saintvincentius is a species of sea slug or dorid nudibranch, a marine gastropod mollusk in the family Chromodorididae.

Distribution
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 -35.04426°N, 137.73989°W. 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.

Description
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.