Opisthobranch of the Week Data
Cuthona diversicoloris an attractive tergipedid and is considered to be very rare in Okinawan waters; I've not personally seen nor collected any specimens and it is unknown from Okinawa's main Island, but it has been photographed and collected by Atsushi Ono in the Kerama Islands. The close proximity of the main island of Okinawa to the Kerama Islands, as well as the similar opisthofauna to that of the Kerama Islands, suggests the possibility that it is also present here on Okinawa proper. The above featured animal is one which was photographed in the waters of Amuro Island, one of a series of islands in the Kerama Islands Group, which are located 30 ~ 40 kilometers west of the Okinawa capitol, Naha. This featured animal was photographed by Atsushi Ono during February of 2000, from the waters off the East Area of Amuro Island, in 25m of water. Atsushi's beautiful photograph is used here with his kind permission; it should be noted that Atsushi considers the species to be rare in the Kerama Islands in as much as he has seen only two animals, both the same size (pers. comm.).
Cuthona diversicolor was originally described by Baba (1975) as Trinchesia diversicolor. Baba's specimens (35 animals, designated as a type series*) were collected from shallow waters of Akasumi (37° 03'N, 136° 44'E), west coast of Noto Peninsula (Akasumi; Koura), in mainland Japan.
There are seven described species of Cuthona featured on these pages as of December, 2007, found in Okinawan waters. The seven are:
C. acinosa C. diversicolor The above featured animal C. ornata C. pupillae C. purpureoanulata C. sibogae C. yamasui
*type series: See
"Type" Dictionary for explanation.