Ophiomoeris obstricta ( Lyman, 1878 )

Ophiomoeris obstricta ( Lyman, 1878) View in CoL

Ophioceramis (?) obstricta Lyman, 1878: 124–125 View in CoL , pl. 6(164–166). — Lyman, 1882: 26–27, pl. 11(1–3).

Ophiomoeris obstricta View in CoL . — Koehler, 1904: 17. — Koehler, 1922a: 38–39, pl. 5(3–4). — O’Hara & Stöhr, 2006: 120–123, fig. 16a– g. — Martynov, 2010b: 124, fig. 7g –h, 13k, 16q, 36e–h. — O’Hara, 2024b: 48, fig. 48.

Ophiurases obstrictus View in CoL . — Clark, H.L., 1911: 250–252, fig. 122.

Ophiomoeris parva Clark, H.L., 1939: 39–41 View in CoL , fig. 4–5 [according to O’Hara & Stöhr, 2006].

Ophiomoeris cf obstricta View in CoL . — Stöhr, 2011: 23–24 View Cited Treatment , fig. 8c–e.

STUDY MATERIAL. — MD208 : stn CP4882, Walters shoal, Pentes, 33° 16.67´S, 43° 50.4899´E to 33° 16.03´S, 43° 49.84´E, 371–399 m, 2/5/2017: 6 ( MNHN IE.2023.4159) ( DNA code= IE.2023.4159) GoogleMaps . — MD208 : stn DW4885, Walters shoal, Pentes, 33° 16.68´S, 43° 54.18´E to 33° 16.61´S, 43° 54.9301´E, 272–380 m, 3/5/2017: 1 ( MNHN IE.2016.1361) GoogleMaps . — MD208 : stn DW4887, Walters Shoal, Pentes, 33° 17.23´S, 43° 55.44´E to 33° 16.98´S, 43° 56.6899´E, 599–640 m, 3/5/2017: 1 ( MNHN IE.2016.1366) GoogleMaps . — MD208 : stn DW4896, Walters Shoal, Pentes, 33° 7.24´S, 43° 50.3199´E to 33° 6.71´S, 43° 50.8099´E, 325–357 m, 5/5/2017: 1 ( MNHN IE.2013.17158) GoogleMaps .

COMPARATIVE MATERIAL EXAMINED. Ophiomoeris exuta Stöhr, 2011 : EXBODI/CP3848, Banc Durand , 22° 3.5´S, 168° 41.6´E, 430–440 m, 13/9/2011 GoogleMaps , MNHN IE.2023.4007 ( DNA code=CP3848). Ophiomoeris obstricta ( Lyman, 1878) : BIOPAPUA/CP3737, Au large des îles et récifs Lancasay, 8° 15´S, 150° 45´E, 587 m, 9/10/2010 GoogleMaps , MNHN IE.2007.2936 ( DNA code=BP37). Chargos /10, Peros Banhos, Ile de Pierre, 5° 19.118´S, 71° 43.502´E, 250 m, 18/10/2022 ( DNA code=Chargos.262) GoogleMaps . IN2018_ V06 /105, Baseline _29, 44° 5.622´S, 146° 41.298´E to 44° 5.922´S, 146° 40.26´E, 541–560 m, 8/12/2018 GoogleMaps , MV F267820 ( DNA code=F267820). IN2021 _ V04 /5, Christmas Island SE, 10° 34.22´S, 105° 41.376´E to 10° 33.791´S, 105° 41.6358´E, 643–997 m, 6/7/2021 GoogleMaps , identified by O’Hara (2024b), MV F305517 ( DNA code=F305517). MIRIKY/CP3251, au large de Majumga , 15° 23.16´S, 45° 57.75´E to 15° 24.55´S, 45° 56.5602´E, 609–620 m, 8/7/2009 GoogleMaps , MNHN IE.2007.398 ( DNA code= IE.2007.398). SAYA / CP5436 , SW Saya de Malha , 11° 49.972´S, 60° 55.632´E to 11° 49.802´S, 60° 56.275´E, 312– 300 m, 16/11/2022 GoogleMaps , MNHN IE.2023.4267 ( DNA code= IE.2023.4267). TAN1206/99, Site SM3 b, NE of summit, Clark Seamount , Southern Kermadec Ridge, 36° 26.718´S, 177° 50.352´E to 177° 50.418´N, 36° 26.568´W, 850–927 m, 24/4/2012 , MV F188867 ( DNA code=02W2Y) .

Distribution. NW Pacific ( 50–470 m), W Indian Ocean ( 202–1206 m), E Indo-W Pacific ( 35–1901 m), S America ( 180–471 m), S Africa ( 272–640 m), S Australia ( 145–877 m), New Zealand ( 146–1190 m), Walters Shoal ( 272–640 m).

Remarks. O’Hara & Stöhr (2006) synonymised several Indo-Pacific species of Ophiomoeris as their diagnostic characters overlapped. However, subsequent DNA data has revealed much sequence variation within this complex and it is likely that cryptic species are present. The sequenced MD208 sample clusters with a sample from the Saya de Malha Bank, however, specimens from Madagascar and Chargos are distinct and the geographic and bathymetric range of these lineages are unclear. In the interim we continue to use the name Ophiomoeris obstricta for the complex.

The current specimens (to 3.2 mm dd) can have rounded granules on the disc, between the proximal ends of the radial shields and sometimes in the centre of the disc. There are 5–6 arm spines, the upper longest, to longer than a segment, and meet dorsally on the first free segment. The radial shields are separated distally by a triangular plate. Although, the upper arm spine is longer than the others on these specimens, they do not reach the length (3x segment length) shown in the type series of O. parva H.L. Clark, 1939 from the Maldives, which also lacked disc granules.