Ophiologimus prolifer (Studer, 1882)

Ophioscolex prolifer Studer, 1882: 28, pl. 3(13a–e).

Ophiologimus prolifer. — Martynov, 2010b: 70.

STUDY MATERIAL. — JC066: stn 4-12, Coral seamount, 41° 22.333´S, 42° 54.066´E to 41° 23´S, 42° 54.1´E, 730 m, 16/11/2011: 1 (NHMUK 2025.) (DNA code=02W70).

COMPARATIVE MATERIAL EXAMINED. Ophiologimus cf. hexactis SE-1722/10DR, Kumano-nada, 33° 59.72´N, 136° 56.67´E to 33° 59.72´N, 136° 56.68´E, 796– 768 m, 10/11/2017, NSMT E11571 (DNA code=SE-17- 155). Ophiologimus hexactis H.L. Clark, 1911: Sagami Bay, off Misaki, stn1, 35° 8.415´N, 139° 32.944´E to 35° 8.262´N, 139° 32.746´E, 109–160 m, 4/6/2018 (DNA code=Misaki035). Ophiologimus prolifer (Studer, 1882): Gazelle/Barrier Island, off Barrier Island, 35° 21´S, 175° 40´E, 1092.5 m, 12/11/1875, syntype, ZMB Ech2535. SS02/2007/8, 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 (DNA code=TOH_0946). 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 (DNA code=TOH_0425). Ophiologimus quadrispinus H.L. Clark, 1925: EXBODI/DW3918, Récifs de l’Astrolabe- Mont sous-marin Est, 19° 51.9´S, 165° 55.2´E, 748–922 m, 24/9/2011, MNHN IE.2007.7264 (DNA code=IE.2007.7264). Ophiologimus secundus Koehler, 1914: ME 85- 3/1069, South Iceland, Irminger Basin, 62° 59.33´N, 28° 5.7´W to 62° 59.81´N, 28° 5.01´W, 1588 m, 8/9/2011, DZMB-HH 58752 (DNA code=DZMB53422B).

Distribution. New Zealand (170–1110 m), Macquarie Ridge (438–451 m), SE Australia (830–1640 m), Coral Seamount (730 m).

Remarks. The JC066 specimen was preserved in RNALater.An RNA transcriptome was successfully sequenced (O’Hara et al. 2014b), but the remaining specimen was subsequently destroyed through a freezer failure. The COI of this specimen is similar to that from Australian specimens of O. prolifer. The specimens here have 6 arms. They also have one elongated tentacle scale, and three arm spines, the upper being flatter, wider and longer than the others. The upper arm spines are modified into hooks distally. The type of this species (ZMB Ech 2535) is similar, but has 7 arms, but one arm is smaller than the others and may have originated from an injury. It has one lanceolate tentacle scale, 3 arm spines (middle shortest), the DAPs are longer than wide, rounded triangular, and the distal tips of the radial shields are exposed.

Two other 6-armed Ophiologimus species have been described: the type species O. hexactis H.L. Clark, 1911 from Japan and O. secundus Koehler, 1904 from the North Atlantic. The former is distinguished from O. prolifer by the presence of 2 oval tentacle scales. Martynov (2010b) separated O. secundus from O. prolifer by the shape of the oral shield (with a dorsal lobe in O. secundus) and DAPs (contiguous and polygonal in O. prolifer). However, the latter character does not hold good in the present material and may be influenced by size. However, a specimen of O. secundus from Iceland is clearly separated from O. prolifer on our phylogeny (Fig. 2b). Another similar genus is Ophiolycus which appears to differ in having more spine-like inner oral papillae, a 2nd oral tentacle that emerges outside of the slit, and distal oral tentacle scales that are not confluent with the inner ones.