OKINAWAN
OPISTHOBRANCH OF THE WEEK

Trapania euryeia Gosliner & Fahey, 2008 (7mm)

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        Trapania euryeia is considered to be very rare on Okinawa as I have seen and collected a total of only two individuals over a period of more than thirty years of diving here. The above featured animal was collected Christmas day, 1994, from the surface of an algal mat, found near the drop off of a live stony coral reef. A previously collected animal was found associated with a mat of algae as well. Trapania euryeia was in the past listed on these pages as T. brunnea Rudman, 1987, but with publication of the recent Gosliner & Fahey (2008) paper I've now changed the name. The above image is one of the paratype* specimens (CASIZ** 105257), deposited at California Academy of Sciences.

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

Distribution
This species has been reported from Reunion, Papua New Guinea, Indonesia: Sulawesi and Bali, Okinawa, Marshall Islands, Midway Atoll and Hawaii.
External morphology
The living animal ranges from 3-10mm 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 oral tentacles are relatively short and cylindrical with a rounded apex. The posterior end of the foot is sharply tapered with a somewhat rounded posterior tip. The, non-retractile, perfoliate rhinophores are relatively short with 7-8 lamellae and have 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, and slightly longer than the extra-rhinophoral appendages. The body is pale yellow with brown patches that have white or pale yellow punctuated spots showing through the brown. The colour of the anterior head tentacles could not be determined. The bases of the oral tentacles are brown with white dots and the apices are white. The extra-rhinophoral and extra-branchial appendages are creamy white with a few brown spots. The rhinophores and gill leaves are the same colour as the body, that is, pale yellow with random brown blotches.

        Members of the group are readily distinguished from other Okinawan nudibranchs by the presence of a pair of thin finger-like processes located near the rhinophores and gills.

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

  • T. euryeia the above featured animal
  • T. gibbera
  • T. naeva
  • T. squama
  • T. toddi
  • T. vitta
  •         * Paratype: See "Type" Dictionary for explanation.
            **CASIZ: California Academy of Sciences Department of Invertebrate Zoology

    Etymology:

    Literature Cited:


    Page Date: 17 Mar '08
    Page Modification Date: 01 Aug '13
    Digitally manipulated photo
    Copyright © 2013 Robert F. Bolland