Ophiectodia enopla (Verrill, 1885)

Fig. 14a–g

Ophiacantha enopla Verrill, 1885: 153 .

Ophiacantha (Ophiectodia) enopla . — Verrill, 1899: 37, 42.

Ophiacantha veterna Koehler, 1907: 41–43 . — Koehler, 1909: 189–190, pl. 29(3–4). — Martynov & Litvinova, 2008: 96–97, fig. 11d. — O’Hara & Thuy, 2022: 16–17, fig. 6a–b [new synonymy].

Ophiacantha enopla enopla . — Paterson, 1985: 36–37, fig. 16.

Ophiacantha enopla veterna . — Paterson, 1985: 37, fig. 16. — Stöhr & Segonzac, 2005: 392.

STUDY MATERIAL. — JC066: stn 4-4, Coral seamount, 41° 22.8371´S, 42° 50.6024´E to 41° 22.85´S, 42° 51.99´E, 1186 m, 13/11/2011: 1 (NHMUK 2025.37) (DNA code= JC066-648) . — JC066: stn 4-9, Coral seamount, 41° 21.0283´S, 42° 55.145´E to 41° 21.7´S, 42° 54.8´E, 1100 m, 14/11/2011: 1 (NHMUK 2025.38) (DNA code= JC066- 1001) .

COMPARATIVE MATERIAL EXAMINED. Ophiectodia enopla (Verrill, 1885): CE13008/91, Whittard Canyon, 48° 38.15´N, 10° 41.4´W, 2400 m , 6/2013, NUI (DNA code= NUI1666 K) . EX1905 L2/D12-04B, small canyon between Block and Alvin canyons, 39° 49.12´N, 70° 51.2´w, 1138 m, 14/9/2019 , USNM 1596691 (DNA code= USNM 1596691). SS10/2005/54, Pt Hillier, 35° 31.362´S, 117° 12.66´E to 35° 31.566´S, 117° 13.8´E, 1075– 1110 m, 27/11/2005, MV F112618 (DNA code= MVF112618). TN228/J2-389-008, Hill offshore of St. Helens, 41° 14.369´S, 148° 49.325´E, 1286 m, 1/1/2009 , MV F168673 (DNA code=F168673). TAN1402/14, Forde Seamount, Stratum 1, 35° 19.57´S, 170° 26.32´W to 35° 19.42´S, 170° 26.14´W, 1137–1154 m, 9/2/2014, NIWA 94074.

Description. Large specimen (NHMUK 2025.37, 8 mm dd, arms 46+ mm), disc covered in tiny granules, with naked region triangular regions indicating the distal end of the radial shields; oral shields 2x as wide as long, lozenge-shaped, with a small distal lobe; adoral shields thick, almost as long as the oral shields, 2x as wide as long, fully contiguous interradially; 4–5 oral papillae, 3rd & 4th stoutest, almost as wide as long, minutely thorny; arm plates not striated or glassy, separate throughout (except for a few basal DAPs); DAPs triangular to bell-shaped; VAPs 2x as wide as long; to 8 arm spines, uppermost to 2 segments in length, lower ones minutely thorny, becoming hookshaped distally; tiny spine-like tentacle scale, visible until near the arm tip. Small specimen (NHMUK 2025.38, 4 mm dd), disc spines, arm spines and oral papillae spinier than the adult; disc granules with numerous thorns; 3–5 oral papillae, some suboral in position; tentacle scale visible until arm tip.

Distribution. Arctic (1992–1995 m), NW Atlantic (457–1421 m), NE Atlantic (1350–2669 m), E Atlantic (1004–1679 m), Amsterdam & St Paul (940–1680 m), S Australia (900–1650 m), Louisville Ridge (1075–1448 m), Coral Seamount (1100–1186 m)

Remarks. Paterson (1985) and Martynov & Litvinova (2008) separated O. veterna from O. enopla on the basis of the smaller tentacle scales that are absent near the arm tip, and the smaller disc granules with less pronounced thorns. Ophiectodia veterna was recorded from the NE and central N Atlantic and O. enopla from the NW Atlantic Ocean. We have sequenced DNA from specimens on both sides of the Atlantic and throughout the cool temperate Southern Ocean, including from the Coral seamount, and find no bathymetric or geographic structure. This dataset includes a juvenile (Fig. 14a–d) and adult (Fig. 14e–g) from the Coral Seamount that show ontogenetic variations in morphology. The juvenile differs in having relatively larger disc granules with numerous thorns, and more thorny arm spines and oral papillae. Consequently, we consider O. veterna a synonym of O. enopla .