Ophiologimus prolifer (Studer, 1882)

Mills, V. Sadie & O'Hara, Timothy D., 2013, Ophiuroids (Echinodermata; Ophiuroidea) of biogenic habitats on the continental shelf of New Zealand, Zootaxa 3613 (5), pp. 401-444 : 428-429

Ophiologimus prolifer (Studer, 1882)

Ophioscolex prolifer Studer, 1882: 28 , pl. 3(13a–e).—Clark, H.L., 1915a: 174. Ophiologimus prolifer .—Martynov, 2010: 70.

Material Examined. West Coast North Island. TAN1105/137, NIWA 77767 (2).

Comparative Material. Ophiologimus prolifer (Studer, 1882) : TAN0905/119, Iceberg Seamount, 44° 9.49´S, 174° 33.3´W to 44° 9.69´S, 174° 33.14´W, 487–616 m, 28/6/2009, NIWA 69765 (1). SS 02/2007/8, Huon Margin, 44° 1.837´S, 147° 34.776´E to 44° 2.135´S, 147° 34.912´E, 830–1030 m, 31/3/2007, MV F146329 (1). TAN0104/ 333, Pyre Seamount, 42° 43.1´S, 179° 54.57´W to 42° 43.18´S, 179° 54.87´W, 1075– 1008 m, 20/4/2001, NIWA 43985 (1). TAN0205/39, Haungaroa Seamount, 32° 35.75´S, 179° 36.47´W to 32° 36.32´S, 179° 36.09´W, 1252– 1175 m, 17/4/2002, NIWA 60368 (1). TAN0803/69, Macquarie Ridge, Seamount 6, 52° 23.85´S, 160° 39.4´E to 52° 23.91´S, 160° 40.13´E, 451– 438 m, 9/4/2008, NIWA 43108 (1). TN228/J2-387-023, Z39 Seamount, 44° 23.32´S, 147° 15.349´E, 1599 m, 26/12/2008, MV F168729 (1). Ophiolycus farquhari (McKnight, 2003) : NZOI/R437, off NE coast, 39° 35.1´S, 178° 25.08´E to 39° 35.1´S, 178° 23.8´E, 800– 440 m, 16/6/1990, holotype, NIWA 3344 (1).

Description. Disc to 7 mm dd, 6, rarely 7, arms, fissiparous. Disc covered in small overlapping translucent perforated plates embedded in a thin skin, no spines, plated skin extends onto the basal dorsal arm surface; small radial shields present but generally hidden beneath the skin. Jaw and arms covered in a thin skin that obscures the plates. Oral shields wider than long, proximal margin strongly convex, distal margin weakly convex or lobed, rounded lateral angles; jaw longer than wide, oral plates tumid proximally, 8–10 oral papillae, inner oral papillae small and pointed; 2–3 distal oral tentacle scales, slightly enlarged, rounded to spatulate. Dorsal arm plates thin and perforated, broadly triangular, as wide as long, convex distal and slightly flattened proximal margin, narrowly contiguous at base; ventral arm plates longer than wide, convex distal margin, concave lateral margins around large tentacle pore, broadly contiguous; 3 arm spines, subcylindrical to flattened, bluntly-pointed, sometimes wider at the base, subequal or upper and lowest a little wider and longer than the middle spine, short, less than 1 segment in length, distal upper and middle arm spines modified into hooks with 1–2 small teeth besides the terminal one; 1 oval to spatulate tentacle scale, sculptured longitudinal markings, rarely 2 on basal segments. Colour (dry) yellowish-brown.

Distribution. New Zealand (170–1110 m), Macquarie Ridge (438–451 m), SE Australia (830–1640 m), Fiji (294–300 m).

Remarks. This species, recently transferred to Ophiologimus and the Ophiomyxidae by Martynov (2010), is reported here for the first time since the type was collected at 1091 m off Barrier Island, north-eastern New Zealand, by the 1875 German Gazelle expedition. It has since been collected from seamounts or other hard substrata on the continental margins. This species is typically 6–7 armed and often shows signs of fissiparity. Several other similar species occur in the south-west Pacific that also have a skin covered disc and distal upper arm spines transformed into hooks. Ophiologimus quadrispinus H.L. Clark, 1925 has five arms, two tentacle scales and three (four basally) blunt arm spines (see O'Hara & Stöhr 2006). Ophiolycus farquhari McKnight, 2003 is very similar to O. quadrispinus but has arm spines that alternate in number from three to two on succeeding arm segments. This species was retained with uncertainty in Ophiolycus by Martynov (2010) but here we re-assign it to Ophiologimus , as re-examination of the type material indicates that it has all the characters of Ophiologimus , including well-developed hooklets on distal arm segments (as developed as O. quadrispinus and O. prolifer ) and unbroken dorsal arm plates that persist until the arm tip.