Opisthobranch of the Week Data
In spite of forty-two specimens of Dermatobranchus primus being personally collected on Okinawa, I consider it to be uncommon. The reason for this "uncommon designation" is that the species has only been collected from a single site (Tengan Pier) on four separate occasions, but during one of the four collection dives thirty-nine individuals were collected. The above featured animal is one of these thirty-nine specimens collected from beneath the pier. All collected animals were found crawling on the surface of mixed silty-sand and strewn oyster shell rubble beneath the pier. There were no observable prey associated with any of the specimens.
Baba (1976) described the species from material collected in 1957 from Kamekisho, Sagami Bay, Japan. Externally the Okinawa material closely fits Baba's original species description as follows:
On the back there occur longitudinal ridges which are extremely fine, and up to 30 in number. According to the coloured sketch taken from life by the collector, the mantle above is pale yellowish white with ocellated spots disposed on the longitudinal ridges. There is no crescentic black band as that which occurs in Dermatobranchus striatus. The clavus of the rhinophores is black. The head veil is yellowish white. The sides and sole are also yellowish white without markings.
As of the current date (Early-April, 2014) thirteen described species of Dermatobranchus from Okinawa's main island and the Keramas are featured on these pages. These thirteen species are:
In addition, I also have a series of undescribed Dermatobranchus species from local waters.
D. albus D. caeruleomaculatus D. cymatilis D. dendronephthyphagus D. diagonalis D. fasciatus D. fortunatus D. funiculus D. gonatophora D. oculus D. ornatus D. primus - The featured animal above D. rodmani