Opisthobranch of the Week Data
Although I've only collected nine specimens of Chromodoris preciosa, the species is considered to be common on Okinawa, but only at a single collecting locale, Tengan Pier. Observations as to numbers and dates of numerous uncollected animals have not been recorded, but the species is considered rare at sites other than Tengan Pier. The featured animal was found during a daytime dive beneath the pier, crawling in the open on the surface of strewn oyster shell rubble and silty sand. Without actually counting the animals, I'd make a conservative estimate of a hundred or so individuals seen on most dives beneath the pier and associated concrete pilings. This is certainly the most commonly observed opisthobranch at the pier dive area.
The only other chromodorid found on Okinawa having a brown mottled dorsum is Chromodoris rufomaculata, but the attractive and very distinctive narrow light blue, black, and gold bands at the notum edge serve to make C. preciosa easy to separate from others found here.