Photosymbiotic Ascidians from Nakanoshima Island and Takarajima Island (the Tokara Islands, Ryukyu Archipelago, Japan) with Remarks on the Status of Diplosoma midori (Tokioka, 1954)*

Abstract

We studied the fauna of photosymbiotic ascidians in the shallow reef shore of the Tokara Islands. We collected Lissoclinum bistratum, L. punctatum, Trididemnum clinides, T. cyclops, T. sp. (cf. T. paraclinides), Diplosoma ooru, D. simile, D. simileguwa, D. virens, D. sp. A, and D. sp. B (cf. D. multipapillatum) from four sites off Nakanoshima Island and one site off Takarajima Island. Diplosoma midori (Tokioka, 1954) is a photosymbiotic ascidian that was originally described from Nakanoshima Island and Takarajima Island. Although there is argument as to the taxonomical status of this species, the conditions of the syntype specimens were inadequate for examining detailed features for identification. Based on the topotype specimens from Takarajima Island, we concluded that D. midori should be regarded as an invalid species, and is a junior synonym of D. simile or D. virens.