OKINAWAN
OPISTHOBRANCH OF THE WEEK

Plocamopherus maculatus (Pease, 1860) /ca. 80mm
Photo Randy Birt

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        This attractive Polycerid, Plocamopherus maculatus, is one which was photographed by Randy Birt, but not collected, from approximately 11 meters during an early evening night dive in February of 2012. The photographs are from an Okinawan site commonly referred to as "Kadena North" by local divers. Randy's photos are used here with his kind permission. I've added a second page with two additional photos, also taken by Randy. During many years of Okinawa diving I never found P. maculatus and Randy reports (pers. comm.) finding only the single featured individual and of course considers it to be very rare.

There is also an image and discussion of P. maculatus on the Sea Slug Forum (Rudman,2003), as well as additional links.

        The following information on the external morphology of Plocamopherus maculatus is taken from Vallès and Gosliner (2006):

External Morphology: In life the body is elongate, limaciform and anteriorly rounded. The head has a wide flattened and fringed oral veil with numerous papillae. The oral tentacles are flat. Plocamopherus maculatus has translucent white background coloration. Typical of the species are the red-orange dots on the dorsum between the rhinophores and in the central part of the dorsum as well as crimson and white pigment surrounding the base of the branchial leaves. The whole body is slightly and regularly speckled with minute brown-orange dots. The rhinophores are for their entire length translucent white and are speckled with minute crimson dots as is the rest of the body. The rhinophoral sheaths are short. There is only one pair of lateral appendages situated behind the branchial leaves that bears the white globular structure. There are two pairs of slightly ramified conical tubercles at the tip at each side of the body. There are five tripinnate branchial leaves, which are elongate. The posterior portion of the foot is elongate and thin, and has a small keel that is slightly fringed on its upper margin.

        Previously I've featured several members of the genus Plocamopherus on these pages and as of the current date (mid-March, 2012) there are several described and undescribed species reported from Okinawan waters. These featured animals are as follows:

  • P. ceylonicus
  • P. imperialis
  • P. maculatus (the above featured animal)
  • P. tilesii
  • P. species 1
  • P. species 2
  • P. species 3
  • Etymology:

    Literature Cited:


    Page Date: 19 Mar '12
    Page Modification Date: 19 Mar '12
    Digitally manipulated photo
    Copyright © 2012 Robert F. Bolland