Calliaster elegans Döderlein, 1922

Döderlein, 1922: 49; Kogure & Fujita 2012: 255

Diagnosis

Body stout, stellate (R/r=2.7–2.9, arms thick, elongate, interradial arcs curved.Abactinal plates flat to weakly convex with surface bare, no surficial accessories. Abactinal plates with large quadrate peripheral granules forming distinct border between plates. Large prominent conical spines on primary disk plates, decreasing in size along carinals to proximal arm plates. Superomarginal plates form distinct border around disk (n=4 free on disk) and arms, occupying approximately 30% of distance “r” between disk center and edge, abutted along majority of arm distance with five pairs of superomarginals in contact. Superomarginal plates covered by large, single conical spines, 1 to 5, directed dorsally on proximal plates, becoming oriented more laterally on subsequent marginal plates. Inferomarginal plates with 1 to 3 prominent conical pointed spines directed laterally in series. Marginal plates smooth with no surficial granules or other accessories. Actinal intermediate plates quadrate to irregular in shape, limited to disk, surface bare except for large single conical spine per plate. Furrow spines, 4–5 (6 in Japanese specimen). Subambulacral spines, one to two in transverse series adjacent to furrow. Paddle-like pedicellariae present.

Comments

The specimen described by Kogure & Fujita (2012) closely resembles the holotype (Döderlein, 1922) with which it shares similarities in spination, abutted superomarginal plates, superomarginal plate number along the disk and arms, as well as pedicellariae type. Döderlein’s specimen is larger (R= 2.2 cm) than the Japanese specimen (R=1.58) but has fewer furrow spines (4 to 5) and more subambulacral spines (n=2) than the Japanese specimen, with six furrow spines and a single subambulacral spine.

In contrast, the specimen described by A.H. Clark (1952) from the Marshall Islands differs in several respects, including the extent of abutted superomarginal plates, superomarginal plate number and to a lesser extent spination. Superomarginal plates, furrow spines and several other characters, such as consistent abactinal spine arrangement on Clark’s specimen numbers 10–13 at R=4.4 also differ significantly. These characters separate USNM E7365 as a distinct species from Calliaster elegans, which is currently in description. It should be noted however, that Calliaster and several of its species appear to be highly variable and taxonomic concepts are poorly understood (see Mah 2018).

Occurrence

Kumejima Island, Japan, 126– 136 m.

Flores Sea, Indonesia, 113 m.

Material Examined

USNM E7365, Off Bikini Island, Bikini Atoll, Ralik Chain, Marshall Islands, 11.62, -165.55, 122–137 m. Coll. R.D. Russell, 14 Aug, 1947. 1 dry spec. R=4.4 r=1.7.

Comment

Taxa represented herein have not yet been conclusively supported as part of a distinct subgrouping within the Goniasteridae. Comments on affinities are included with each genus (or other appropriate) heading.