Diniatys dentifer (A. Adams, 1850) ca. 10mm
Photo by Jun Imamoto

Opisthobranch of the Week Data


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

Species Account:

        The above featured animal, Diniatys dentifer, was photographed by Jun Imamoto from Zamami Island in the Kerama Islands, 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 found by Jun during March of 2002 in 7m of water from an area of mixed sand and dead coral. I've added a second image of D. dentifer (ca. 4mm) which was also photographed by Jun from the same locale as the above featured animal, but on 7 July, 2002. I've not personally seen D. dentifer in the waters of Okinawa's main island but Jun reports (per. comm.) seeing numerous individuals in both the Kerama Islands and the Amami-Oshima Islands (Kagoshima Prefecture, Japan).

        Carlson & Hoff (2000) have an image of a 5mm animal from Tulamben, Bali, Indonesia, posted on the Sea Slug Forum which would appear to be very similar to Jun's animal featured above. Carlson & Hoff mention that Diniatys dentifer is by far the most common haminoeid in their collections (represented by records of over 800 specimens from Guam and the rest of the Micronesian area, as well as others from the Philippines, Indonesia and PNG). In the same posted message the authors go on to say that the major host is the blue-green algae, Lyngbya majuscula and that it has also been found on Schizothrix and Hormothamnion (also blue-greens). Additionally, Carlson & Hoff (2000) point out the following characteristics based on their observations:

The genus Diniatys Iredale, 1936 [as a replacement for Dinia H & A Adams, 1854] is based upon shell alone. It's most distinguishing characteristic being a 'tooth-like' projection* on the columella. The D. dentifer we have found are generally various shades of brown with a darker amorphous brown band on the midline of the head. Some have been found that are somewhat green in color and others without the band on the head. Adult forms found in Bali and Tinian have been smaller than those from Guam. Those from Guam smaller than Palauan specimens. All of those checked have had almost the same shell shape, radula, gizzard plates, jaw elements and gross morphology of the male genital system.
*[there is a photograph on the Sea Slug Forum of the "tooth-like" projection on the columella]

Literature Cited:

Page Date: 26 Jan '04
Page Modification Date: 26 Jan '04
Digitally manipulated photo
Copyright © 2004 Robert F. Bolland