Freyastera tuberculata (Sladen 1889)

Freyastera tuberculata (Sladen, 1889)

Freyella tuberculata Sladen, 1889:638–640, pl. 117: figs. 1–3.—Alcock, 1893a:121.—Korovchinsky and Galkin, 1984:1214[key].

Freyellidea tuberculata.—Fisher, 1917:429.—H.L. Clark, 1920:113.

MERISTICS.—Arms = 6, R = 240 mm, r = 6 mm, R/r = 40/1, length of gonadal region = 30 mm, length of longest arm spine = 7 mm.

DIAGNOSIS.—[80.a] Madreporite huge; [100.c] madreporite subtubercular; [110.f] abactinal disc plates flat, hexagonal; [120.c] abactinal disc plates imbricate; [130.a] abactinal disc plates each armed with a short, sharp spinelet sheathed in membrane bearing many small pedicellariae; numerous larger pedicellariae on disc; [205.a] gonadal region of arms not highly inflated; [210.f] gonadal region of arms covered abactinally with very regular mosaic of squarish, thin plates, larger than those of disc, beyond gonadal region, plates scattered, fewer and thinner, but occurring all the way out the arm; [240.a,c] abactinal arm plates bearing a single tubercle with a glassy spinelet; [280.a] marginal plates small; [290.a] marginals thin, round, reduced; [310.a] marginals bearing single delicate acicular spine; [320.b] adambulacral plates longer than high; [330.f] adambulacral plates dumbbell-shaped, well separated from adjoining plates by muscle tissue in which is sometimes embedded a few small irregular plates or calcite deposits; [340.b] furrow margin slightly indented; [350] furrow spines absent; [380] number of subambulacral spines 1; [390.a] subambulacral spines long, delicate, glassy, borne on tubercle on actinal face of plate; [420.b] ambulacral plates rather small, elongate; [430.d] head of ambulacrals long, cylindrical; [470.b] tubefeet rather heavy; [480.c] mouth plates large; [490.c,f] mouth plates wedge-shaped, with median keel; [500] number of preoral spines per mouth plate 1; [530] lateral oral spines absent [560] number of suboral spines per mouth plate 1; [580.a] suboral spines above center of mouth plate; [620.a,b] all spines covered with delicate membrane bearing many pedicellariae, disc and arm plates bearing larger scattered pedicellariae; [630.a,b] both large and small pedicellariae present.

COLOR.—Grayish white, with light pink tinge to gonadal region (in alcohol).

TYPES.—BM(NH) 90.5.7.1–76–1077 (2 syntypes); Challenger Sta 89, between Canary Islands and Cape Verde Islands, 22°18′N, 22°02′W, 4389 m; Sta 346, between W coast of Africa and Ascension Island, 2°42′S, 14°41′W, 4298 m.

MATERIAL EXAMINED.—Syntypes; 1 specimen, USNM E931, Albatross Sta 4742, Eastern Tropical Pacific, 0°03′N, 117°15′W, 4243 m; 1 specimen, USNM E20797, Pillsbury Sta 1372, mid-Atlantic, 23°14′N, 64°49′W, 5618 m.

DISTRIBUTION.—Apparently cosmopolitan; Alcock (1893a) also reported it from the Indian Ocean.