OKINAWAN
OPISTHOBRANCH OF THE WEEK

Hoplodoris grandiflora (Pease, 1860) 16mm
Photo by Atsushi Ono

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        Hoplodoris grandiflora is considered to be uncommon in Okinawan waters; I've not personally seen the animal here on Okinawa's main island, however I've previously featured several additional members of the genus from Okinawan waters (included in the list below). Atsushi mentions (pers. comm.) seeing five individuals in the Keramas* and four of these were about 50mm. At 16mm the above featured animal is considered to be a juvenile. I've added a second image of another specimen of H. grandiflora from the Keramas, also kindly furnished by Atsushi.

        I've taken the following description of external morphology of Hoplodoris grandiflora from the recent review of Hoplodoris by Fahey & Gosliner (2003):

EXTERNAL MORPHOLOGY.- The preserved animals range from 23-55 mm in length. The body is oval, flat and the notum is covered with large, rounded tubercles that decrease in size towards the mantle edge. The rhinophores are closely-set and stout, with a knob-shaped lamellar region (10-15 lamellae) that terminates in a point. The low rhinophore sheaths have an irregular edge and small tubercles on the sides. The six main gill leaves are tripinnate, feathery and the tubercle-covered sheath has a scalloped edge.
The ground color of the notum is light to medium mottled brown or tan. Lateral to either side of the dorsal median on some specimens are evenly spaced clumps of darker tubercles. Some specimens have dark spots near the mantle edge or have areas of white tubercles that appear as perpendicular rays along the mantle edge. The clumps of dark tubercles merge on some specimens into a dark ring. On the knobby tops of some tubercles, the brown coloration appears worn off and whitish coloration is visible. The gill leaves are lighter tan than the body color, with a frosted appearance on the tips. The rhinophores are also lighter tan than the body and the tips are white.
On the ventral side of some preserved specimens, dark spots are sprinkled randomly. The digitate oral tentacles have also retained some of the dark speckles, and the oral tube has dark coloration. The foot is notched at the anterior end.

        The Sea Slug Forum (2003) lists the distribution of H. grandiflora to be Hawaii, Philippines, Palau, Kerama Islands, Mauritius, Tanzania, and Madagascar.

        Previously I've featured several members of the genus Hoplodoris on these pages and as of the current date, there are three described species reported from Okinawan waters. These three species are as follows:

  • H. bifurcata
  • H. estrelyado
  • H. grandiflora (the above featured animal)
  • Literature Cited:

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


    Page Date: 15 Nov '04
    Page Modification Date: 15 Nov '04
    Digitally manipulated photo (image has been horizontally flipped)
    Copyright © 2004 Robert F. Bolland