Freyastera mexicana (A. H. Clark 1939)

Freyastera mexicana (A.H. Clark, 1939)

Freyella mexicana A.H. Clark, 1939a:442.—Korovchinsky and Galkin, 1984:1213 [key].

MERISTICS.—Arms = 6, R = 110 mm (estimated), r = 5.5 mm, R/r = 20/1, length of gonadal region = 24 mm, length of longest arm spine = 1 mm.

DIAGNOSIS.—[80.a] Madreporite large; [90.b] madreporite lying in smooth, conical pit surrounded by many long spinelets; [100.d] madreporite with single S-shaped pore; [110.e] abactinal disc plates scale-like; [120.b,c] abactinal disc plates dense, slightly imbricate; [130.a] each abactinal disc plate bearing usually 1, sometimes 2 or 3 rough, glassy spinelets; [180.a] arms long, very attenuate; [205.a] gonadal portion of arms slightly inflated, set off abruptly from rest of arm; [210.f] abactinal arm plates flat, squarish, ending abruptly beyond gonadal region, distal portion of arms covered only by thin membrane; [240.a,c] abactinal arm plates bearing about 5 tubercles, each with a rough, glassy spinelet, membrane beyond gonadal region bearing scattered tiny pedicellariae; [280.a] marginal plates small; [290.b,e] marginal plates oval, flat, inconspicuous; [320.b] adambulacral plates longer than high; [330.a] adambulacrals cylindrical; [340.b] furrow margin slightly indented; [350] number of furrow spines 1; [380] number of subambulacral spines 1; [390.a] subambulacral spines large, glassy, mounted on conspicuous tubercle, 2 or 3 very delicate, setose small spines in diagonal line with larger spine, on inner distal edge of adambulacral; [420.a,b] ambulacral plates rather low proximally, quite high distally; [430.a] head of ambulacral plates more or less cylindrical, but not larger than base, waist of plates quite broad, the whole plate looking like a stout anvil: [470.b] tubefeet rather heavy: [490.c] mouth plates triangular, well separated from adjoining mouth plates, about as broad as long, with proximal lateral boss or extension; [500] number of preoral spines per mouth plate 3 or 4, moderately long; [510.b] preoral spines blunt; [520.a] preoral spines behind adoral margin; [530] number of lateral oral spines per mouth plate 2 or 3; [540.a] lateral oral spines small, very delicate, setose; [550.a,c] one lateral oral spine proximal, one or two distal; [560] number of suboral spines per mouth plate 2, large, stout; [570.c] suboral spines blunt; [580.a] suboral spines above center of mouth plate; [620.a,b] pedicellariae abundant on disc, arms, and all spines, those on spines quite large; [630.a,b] both large and small pedicellariae present.

COLOR.—Unknown.

TYPE.—USNM E5602 (holotype); Albatross Sta 2379, Gulf of Mexico, 28°N, 87°42′W, 2683 m.

MATERIAL EXAMINED.—Holotype.

DISTRIBUTION.—Known only from type-locality.