The Geometric Chromodoris (Chromodoris geometrica) nudibranch belongs to the Chromodorididae family. It is widespread throughout the Tropical Indo-West Pacific and can be found in locations such as Papua New Guinea, Fiji, the Philippines and the east coast of Australia. It is considered to be a tropical species and occasionally larvae will settle in southern NSW at locations such as Port Stephens and Sydney.
Chromodoris geometrica was originally described from New Caledonia. The body is a black colour with a purple pattern that resembles a phyllidiid and the gills and rhinopores of the species are a yellow/orange colour. The gills generally have green/orange colouration on the tips. The underside of the anterior mantle has a bright purple colour and this can often be seen when the species moves around. Chromodoris geometrica grows to a maximum size of approximately 8cm.
