OKINAWAN
OPISTHOBRANCH OF THE WEEK

Dermatobranchus rodmani Gosliner & Fahey, 2011 (10mm)
Photo by Atsushi Ono

Opisthobranch of the Week Data

Taxonomy:

Frequency in Okinawan waters: Collection Data:
[brackets indicate range for all Okinawa-collected specimens of the species]


Species Account:

        The current featured animal, Dermatobranchus rodmani, is unknown from Okinawa's main island as of early-January, 2013. The above animal is one which was photographed by Atsushi Ono from an area "between coral rubble and small rocks" in 8 meters of water off Gahi Island in the Keramas* during Jan of 2012. Atsushi's photographs are used here with his kind permission. It should be noted that Atsushi has seen in excess of 10 specimens and therefore considers the species to be uncommon in the Kerama Islands (pers. comm.). I've also added a second page with an additional image of Atsushi's animal.

        The following is taken from Gosliner & Fahey (2011):

External morphology: The body shape of the living animal is elongate and triangular, flattened, and narrows at the posterior end. The foot projects only slightly beyond the distinct mantle margin. The notum is smooth and fleshy. There are three low, distinct longitudinal ridges in the larger specimen from Malaysia and no ridges are evident in the material from Madagascar. The oral veil extends forward and has rounded corners. The widely spaced, club-shaped rhinophores are situated behind the oral veil. They have a series of longitudinal lamellae on the rounded club. The stalk does not narrow noticeably. Marginal sacs are visible along the mantle edge and each contains elongate, stiff rodlets. There are no branchial or hyponotal lamellae. The genital opening is on the right side of the body, near the anterior quarter of the body. The anus is situated approximately one-third of the way to the posterior end of the body.

The ground colour of the notum, the oral veil, and the foot is pale pinkish white to tan. One or two transverse brown patches are present near the anterior and posterior thirds of the body. The notum and oral veil have a yellowish margin, which may contain fine punctations of brown. The rhinophores, including the base, lamellae, and apex, are brown with a few opaque white spots on their surface.

        As of the current date (September, 2016) thirteen described species of Dermatobranchus from Okinawa's main island and the Keramas are featured on these pages. These thirteen species are:

  • D. albus
  • D. caeruleomaculatus
  • D. cymatilis
  • D. dendronephthyphagus
  • D. diagonalis
  • D. fasciatus
  • D. fortunatus
  • D. funiculus
  • D. gonatophora
  • D. oculus
  • D. ornatus
  • D. primus
  • D. rodmani - The above featured animal
  • In addition, I also have a series of undescribed Dermatobranchus species from local waters.

    Etymology:

    Literature Cited:


            * Keramas = the Kerama Islands Group, located 30 ~ 40 kilometers west of the Okinawa capitol, Naha.


    Page Date: 07 Jan '13
    Page Modification Date: 01 Sep '16
    Digitally manipulated photo
    Copyright © 2016 Robert F. Bolland