[New Japanese name: Hanayaka-togesugata-hitode]

(Fig. 2)

Calliaster elegans Döderlein, 1922: 49; 1924: 62. — A.H. Clark 1952: 284. — Jangoux et al. 1989: 168. — A.M. Clark 1993: 246.

Material examined. One specimen, RUMF-ZE-00033, KUMEJIMA 2009 Stn. Trawl-27, 26° 16.961 –17.028 ʹN, 126° 51.952 –52.508 ʹE; 126–136 m, 12 November 2009.

Description. A small specimen (Fig. 2A) with R = 15.8 mm and r = 5.4 mm (R/r = 2.9). One regenerating arm. Abactinal, actinal and marginal plates with smooth surface, more or less inflated. All plates fringed with coarse granules (Fig. 2B, C). Most of plates topped by one conical spine. Considerable loss of spines observed; but shallow hollows formed by broken spines on plates showing pattern of spine arrangement.

Abactinal plates round or elliptical in shape. Conical spines on 3rd to 5th carinal plates, as well as on central 9 abactinal plates.

Number of superomarginal plates, 6; inferomarginal plates, 6. Superomarginal plates tumid; 5 distal plates abutting each other over radial midline. First and 2nd superomarginals each bearing 2 spines; 3rd to 5th plates with single spine; 6th plate lacking spines; terminal plate with 2–4 spines. Inferomarginal plate also tumid with 2–3 spines near upper edge.

Each interradial actinal surface composed of 10–11 rounded square or rounded triangular actinal plates surrounded by 1st inferomarginal, adambulacral, and mouth plates. Two largest actinal plates situated in center of each interradial area, bearing conspicuous paddle-like pedicellariae (Fig. 2D).

Each mouth plate having 7 marginal spines (furrow series). Three suboral spines pointing upward; middle suboral spine longest, reaching up to 2 mm.

Number of adambulacral plates, 26; each plate bearing 6 furrow spines. Proximal 2–3 adambulacral plates having one robust, conical subambulacral spine. No pedicellariae on adambulacral plate.

Distribution. This species was known from the Flores Sea, Indonesia (type locality), and Marshall Islands at depths of 113–137 m (A.H. Clark 1952). The present study represents the first record of the species from Japan. The distribution range of the species is extended to north.

Remarks. Calliaster erucaradiatus Livingstone, 1936, known from Australia, closely resembles this species. The presence of the pedicellariae is used to distinguish C. elegans from C. erucaradiatus (Livingstone, 1936). However, recent examination of C. erucaradiatus specimens from Taupo Seamount, Australia, revealed the existence of small pedicellariae. This fact suggests that C. erucaradiatus may be synonymous to C. elegans (H.E.S. Clark & McKnight 2001). Examination of further specimens of this seldom encountered species would be required to determine the exact relationship between C. erucaradiatus and C. elegans. In the present study, we identified our material as C. elegans, based on the presence of remarkable pedicellariae.