Ophiomyxa Müller & Troschel, 1840

Stöhr, Sabine, 2004, Ophiuraster patersoni Litvinova, 1998 is the postlarva of Ophiomyxa serpentaria Lyman, 1883 (Echinodermata, Ophiuroidea), Zoosystema 26 (1), pp. 95-105 : 97-98

Genus Ophiomyxa Müller & Troschel, 1840

Ophiomyxa serpentaria Lyman, 1883 ( Figs 2-4 )

Ophiomyxa serpentaria Lyman, 1883: 274 , pl. 8 figs 114-116.

Ophiodera serpentaria – Verrill 1899: 67.

Ophiodera serpentina – Koehler 1909: 203 (misspelling).

Ophiuraster patersoni Litvinova, 1998: 441 .

MATERIAL EXAMINED ( Table 1, Fig. 1 ). — Off Iceland. A total of 15 postlarvae and 25 adult specimens: stn 2410, 1 spec. on SEM stub ( SMNH-46115 ) ; 2 specs in ethanol ( SMNH-51874 ) ; stn 2898, 3 specs in ethanol ( SMNH-51868 ) ; stn 3012, 2 specs on SEM stub ( SMNH-51873 ) ; stn 2914, 2 specs in ethanol ( SMNH-52035 ) ; remaining samples ethanol, lodged at NI (no catalogue numbers).

COMPARATIVE MATERIAL. — Ophiuraster patersoni, Bay of Biscay, BIOGAS 6, stn D586, N.O. Jean Charcot, 44°05’N, 4°19’W, 1950 m, 31.X.1974, holotype ( MNHN EcOs 4895). — Ophiuraster belyaevi, Kerguelen Islands, MD 04, stn I106 CP258, 48°43’5”S 71°06’5”E, 925 m, 13.III.1975, holotype ( MNHN EcOs 5839). — “ Poraniidae ”, BIOFAR, stn 158, 61°58.3’N, 5°38.2’W, 322 m, 7.V.1988 (data from NØrrevang et al. 1994), 3 specs in ethanol ( KMBL, no catalogue number).

REMARKS. — The dd among the studied postlarvae ranges from 1.8 to 2.5 mm, while the number of arm segments ranges from 2 to 16, with considerable variation in the larger individuals ( Fig. 2 ). Adult specimens range from 16.0 to 25.0 mm dd, with arm lengths of 65.0 to over 100.0 mm. Unfortunately, the maximum arm length could not be determined, because all larger individuals are badly damaged with arms broken. All animals are covered with smooth thick skin, which obscures the plates.

Figures

FIG. 2. — Growth series of postlarval Ophiomyxa serpentaria Lyman, 1883, dorsal and ventral aspects; A, B, dd 1.8 mm, 2 as, stn 3012; C, D, dd 1.9 mm, 3 as, stn 3012; E, F, dd 2.2 mm, 7 as, stn 2914; G, H, dd 2.3 mm, 9 as, stn 2914; I, J, dd 2.5 mm, 11 as, stn 3012; K, dd 2.5 mm, 13 as, stn 2410; L, M, dd 2.5 mm, 16 as, stn 3012. Abbreviations: as, arm segments; dd, disk diameter; stn, BIOICE station number. Scale bar: 1 mm.

FIG. 3. — Scanning electron micrographs of postlarvae of Ophiomyxa serpentaria Lyman, 1883; A-F, dorsal and ventral aspects; A, B, dd 1.8 mm; C, D, dd 2.0 mm; E, F, dd 2.5 mm; G, H, swollen, hollow terminal arm segments with dd 2.0 and 2.5 mm. Skin partially removed. Abbreviations: dd, disk diameter; FLAP, first lateral arm plate; LMP, lateral mouth papillae; RPP, radial primary plates; RS, radial shields. Scale bars: A-F, 1 mm; G, H, 0.1 mm.

FIG. 4. — Ophiomyxa serpentaria Lyman, 1883, scanning electron micrographs; A, distal postlarval arm with swollen terminal segment; B, postlarval arm, lateral plates and spines; C, adult, mouth; D, adult, proximal arm spines; E, adult, distal arm spines; F, adult proximal arm spine and long, flat tentacle scales. Skin partially removed, disk diameter of postlarva 2.5 mm, of adult 16 mm. Abbreviations: AdS, adoral shield; AS, arm spine; LAP, lateral arm plate; MP, mouth papillae; OS, oral shield; SP, sheath plate. Scale bars: A, B, D-F, 0.1 mm; C, 1 mm.

FIG. 1. — BIOICE collecting stations of Ophiomyxa serpentaria Lyman, 1883 (Iceland waters).