Thorunna halourga is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae.[1]
This species was described from Rasch Passage, Madang, Papua New Guinea and Batangas, Philippines. It has been reported from tropical eastern Australia.[2]
The mantle is a pale lilac becoming purple in front of the rhinophores and behind the gills. The mantle margin, which is slightly undulate, has a broad white band. The rhinophores have a purple stalk and the lamellae are edged with orange. The gills are white with orange axes.