Ophionereis novaezelandiae Mortensen, 1936

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 : 431-432

Ophionereis novaezelandiae Mortensen, 1936

( Fig. 13 b)

Ophionereis novae-zelandiae Mortensen, 1936: 299 –301, fig. 29.—Fell, 1952: 23.—Clark, A.M., 1953: 70. Ophionereis porrecta .—McKnight, 1993a: 175, 188 [Non Ophionereis porrecta Lyman T, 1860 ]. Ophionereis terba Baker & Devaney, 1981: 158 –161, fig. 30.—Rowe & Gates, 1995: 410.—O'Hara, 1998: 44–45, fig. 2 [new

synonymy].

Material Examined. Bay of Islands. KAH0907/164, NIWA 58372 (1). KAH0907/195, NIWA 77668 (1). TAN0906/2, NIWA 77672 (3). TAN0906/3, NIWA 77673 (4). TAN0906/21, NIWA 54706 (1). TAN0906/30, NIWA 54832 (1). TAN0906/60, NIWA 77644 (28). TAN0906/81, NIWA 77663 (1); NIWA 55444 (1). TAN0906/ 96, NIWA 77645 (38). TAN0906/99, NIWA 55680 (10); NIWA 55682 (1); NIWA 55794 (3). TAN0906/105, NIWA 77674 (2). TAN0906/130, NIWA 56028 (6). TAN0906/143, NIWA 77671 (2). TAN0906/170, NIWA 77664 (2). TAN0906/205, NIWA 57193 (4). TAN0906/235, NIWA 77665 (1). East Coast North Island. TAN1108/197, NIWA 77676 (4). TAN1108/233, NIWA 63309 (8). TAN1108/250, NIWA 75558 (1). TAN1108/253, NIWA 77670 (5). TAN1108/268, NIWA 77646 (9). TAN1108/275, NIWA 77669 (1). Far North. TAN0906/154, NIWA 77666 (1). TAN0906/159, NIWA 77675 (2). TAN0906/164, NIWA 77667 (1). Three Kings Islands. TAN1105/35, NIWA 77643 (11). TAN1105/42, NIWA 73197 (39). TAN1105/69, NIWA 73497 (21). TAN1105/70, NIWA 73577 (10).

Comparative Material. Ophionereis novaezelandiae Mortensen, 1936 : NZOI/B41, 39° 12´S, 177° 8.1´E, 17 m, 2/9/1957, NIWA 43155 (1). Discovery/934, North of New Zealand, 34° 11´S, 172° 10´E, 92–98 m, 17/8/1932, holotype of Ophionereis novae-zelandiae , BMNH 1936.12.30.839 (1). MFG/1, 45 Km SSW of Portland, 38° 40´S, 141° 20´E, 293–585 m, 14/5/1979, holotype of Ophionereis terba , MV F45363 (1). BSS/84 G, Western Bass Strait, 73 km W of Cape Farewell, King Island, 39° 34´S, 143° 6´E, 171 m, 11/10/1980, MV F90465 (7). NZOI/P6, Wanganella Ridge, 32° 36.8´S, 167° 30.6´E, 127 m, 25/1/1977, identified by McKnight (1993a) as Ophionereis porrecta , NIWA 77754 (1). NZOI/T228, 29° 16´S, 177° 59.1´W, 45 m, 22/3/1982, NIWA 77693 (6). SS 02/2007/4, Huon 200m, 43° 58.701´S, 147° 32.299´E to 43° 58.34´S, 147° 31.943´E, 180–237 m, 29/3/2007, MV F144841 (1). SS 04/04/72, Pieman Canyon, 41° 47.71´S, 144° 35.15´E, 174 m, 22/4/2004, MV F 101739 (50).

Description. Disc diameter of specimens from biogenic habitats was up to 9.8 mm. Disc plates creamy white dorsally and ventrally, sometimes bordered by darker brown. Radial shields small (1/8 dd) and separated by three rows of disc scales. Disc scales longer on disc margin (as in O. fasciata ) but otherwise coarse and consistent over entire disc. Genital papillae small, granule-like and line slit, which extends to disc margin. Oral shields spade to pentagon shaped with small distal extension. Adoral shields narrowly meet. Square oral papillae, 4th distal-most widened.

Dorsal arm banded orange and white, with two small white dots on distal margin of each arm plate. Dorsal arm plates squarish-oblong, accessory plates small, narrow (approximately 1/5th of dorsal arm width) but extend same height as dorsal arm plate. Rounded fan shaped ventral arm plates with large oval tentacle scale. Ventral arm with white band running down midline on proximal plates. Ventral arm plates with rounded distal margin. Arm spines banded cream with 1–2 brown stripes. Three arm spines throughout arm, subequal on proximal segments, but middle arm spine longest after 5th arm segment.

Distribution. Northern New Zealand (17–402 m), south-eastern Australia (53–585 m).

Remarks. Baker (1977) synonymised Ophionereis novaezelandiae Mortensen, 1936 with Ophionereis fasciata Hutton, 1872 as he considered Mortensen’s 4 mm dd holotype specimen to be a juvenile form of O. fasciata , having fewer arm spines, less well developed genital papillae and shorter supplementary arm plates. However, examination of the recent collections shows that differences between the species are consistent in animals of similar disc diameter. Ophionereis fasciata has four arm spines proximally, smaller radial shields, differently shaped dorsal and ventral arm plates, larger accessory dorsal arm plates, and is generally a larger animal than O. novaezelandiae . Egg size is different between these species, 0.1 mm in O. fasciata (Mortensen, 1924) and 0.06 mm in O. novaezelandiae . Moreover, the patterns of colour on the disc and arms are very distinctive ( Figure 13 ) and consistent even in preserved material. The geographic ranges of the two species only overlap on the northeastern coast of New Zealand; O. novaezelandiae extends from the Kermadec islands south to Hawkes Bay, whereas O. fasciata is predominantly southern, only occasionally collected on the north-east coast as far north as the Bay of Islands. Ophionereis fasciata can also be found intertidally.

It seems likely that Baker (1977) actually had juvenile specimens of O. fasciata rather than O. novaezelandiae at his disposal when he synonymised the two species, as did Fenwick & Horning (1980). Both were potentially misled by the key of A.M. Clark (1953) that separated the two species by the supposed absence of genital papillae in O. novaezelandiae . In fact, adult specimens of both species have genital papillae that can be absent or reduced in juveniles. In summary, we recognise Ophionereis novaezelandiae Mortensen, 1936 as a valid species. Historical records of O. porrecta from the Wanganella Bank and around the Kermadec islands are also this species.

A range of specimens of the south-eastern Australian species Ophionereis terba Baker & Devaney, 1981 were examined and compared with specimens of Ophionereis novaezelandiae . Baker & Devaney (1981) did not compare the two species as Baker (1977) regarded O. novaezelandiae as a synonym of O. fasciata . We can find no difference in morphology or colour between the two populations when equal sized specimens are compared and regard O. terba as a junior synonym of O. novaezelandiae .

Figures

FIGURE 13. a: Ophionereis fasciata Hutton, 1872 (NIWA 74208, TAN 1108 / 39) and b: Ophionereis novaezelandiae Mortensen, 1936 (NIWA 55682, TAN 0906 / 99) showing live colour and patterning on the dorsal side of the animals.