OKINAWAN
OPISTHOBRANCH OF THE WEEK

Trapania squama Gosliner & Fahey, 2008 (8mm)
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:

        This attractive little goniodorid, Trapania squama, is unknown from Okinawa's main island as of late-December, 2012. The above featured animal is one which was photographed and collected by Atsushi Ono from an area "between small coral rubble" in 9 meters of water off Gahi Island in the Keramas* during May of 2012. Atsushi's photographs are used here with his kind permission. It should be noted that Atsushi considers the species to be very rare in the Kerama Islands as he has seen and collected only the above depicted individual (pers. comm.).

        There's a similar animal from Papua New Guinea posted on Bill Rudman's Sea Slug Forum as well as a series of images from Kwajalein posted by Scott and Jeanette Johnson.

        I've also added a second page with an additional image of Atsushi's animal.

        The following is taken from Gosliner & Fahey (2008):

External morphology
The living animals range from 4-11mm long. The body shape is elongate and convex, without a distinct notal margin. The body is widest in the branchial region. The head is rounded anteriorly and the anterior foot margin consists of prolonged tentacles. The oral tentacles are relatively long and cylindrical with a rounded apex. The posterior end of the foot is sharply tapered with a somewhat pointed posterior tip. The non-retractile, perfoliate rhinophores are long with 6-9 lamellae. The club is slender and the apex is bulbous with an elongate tip. The extra-rhinophoral appendages are relatively short, thin and have a curved apex. The gill consists of three bipinnate branches. The extra-branchial appendages are curved, about the same size as the extra-rhinophoral appendages. The body is creamy orange with some brown pigment mid-dorsally. Overlaying the orange colour is a distinct pattern formed by black lines that give the appearance of scales. The black lines are outlined with white and on the anterior of the head and behind the rhinophores are streaks of brown pigment. The posterior end of the foot has a brown reticulate pattern. The oral tentacles are orange basally with a brown blotchy pattern apically. The extra-rhinophoral and extra-branchial appendages are muddy brown as are the rhinophores and gill leaves. The rhinophores and gill leaves are white with random brown blotches. The rhinophores have a white, elongate tip.

        Previously I've featured several members of the genus Trapania on these pages and as of the current date (late July, 2013), there are several described species reported from Okinawan waters. The featured animals are as follows:

  • T. euryeia (Okinawa's main island)
  • T. gibbera (Okinawa's main island)
  • T. squama the above featured animal (Keramas)
  • T. naeva (Keramas)
  • T. toddi
  • T. vitta (Keramas)
  • Etymology:

    Literature Cited:


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


    Page Date: 24 Dec '12
    Page Modification Date: 01 Aug '13
    Digitally manipulated photo
    Copyright © 2013 Robert F. Bolland