Ophiacantha metallacta H.L. Clark, 1915

Ophiacantha metallacta H.L. Clark, 1915 View in CoL

Fig 16a–c View FIGURE 16 , 19a–f View FIGURE 19

Ophiacantha vepratica View in CoL . — Koehler, 1914: 94–95, pl. 13(6) [Non Ophiacantha vepratica Lyman T, 1878 View in CoL ; see Clark, H.L., 1915].

Ophiacantha metallacta Clark, H.L., 1915: 202–203 View in CoL . — Mortensen, 1933d: fig. 18b,d. — Paterson, 1985: 44, fig. 19.

STUDY MATERIAL. — JC066 : stn 8-5, Atlantis Bank, 32° 42.862´S, 57° 14.666´E to 32° 43.3´S, 57° 15.2´E, 828–994 m, 10/12/2011: 1 ( NHMUK 2025.32 About NHMUK ) ( DNA code= JC066-3683 ); 1 ( NHMUK 2025.33 About NHMUK ) GoogleMaps .

COMPARATIVE MATERIAL EXAMINED. Ophiacantha metallacta H.L. Clark, 1915 : BIOPAPUA/ DW3719, Vitiaz strait, 6° 3´S, 147° 36´E, 410 m, 7/10/2010 GoogleMaps , MNHN IE.2023.4074 ( DNA code=BP87). EX1806 / D07_01B, Richardson Ridge , 31° 46.2´N, 77° 21.6´W, 1753 m, 21/6/2018 GoogleMaps , USNM 1490594 About USNM ( DNA code= USNM 1490594 About USNM ). Kraken 2/2-2, 24° 14.3322´N, 80° 55.0169´W, 513 m, 29/11/2011 GoogleMaps , MV F248413 ( DNA code=F248413). SS05/2007/156, Northwestern Australia, Leveque L 27 transect, 14° 33.432´S, 121° 20.388´E GoogleMaps to 14° 32.767´S, 121° 19.65´E, 1100 m, 3/7/2007, MV F167998 ( DNA code= TOH _584). TAN1206/34, Site SM3 a, summit of Clark Seamount , Kermadec Ridge, 36° 26.832´S, 177° 50.31´E GoogleMaps to 177° 50.508´N, 36° 26.982´W, 850–980 m, 18/4/2012, MV F188863 ( DNA code=02WOZ) .

Description. Disc 6 mm dd, covered in small disc spines ( Fig. 19e View FIGURE 19 ), typically 0.20 mm high, with a slightly waisted pedicel and a convex crown bearing short divergent points, 0.18 mm across, absent from the radial shields, becoming smaller and conical to spherical in shape ventrally, extend to the oral shields; oral shields 1.5x wider than long, widest proximally with a rounded distal lobe; 3 oral papillae along the jaw sides in addition to 3–8 suboral papillae that can also occur around the adoral shields, tapered apical teeth. Arms not moniliform, vertebrae ( Fig. 19f View FIGURE 19 ) with a pronounced distal zygosphene and zygocondyles further back. DAPs wide and triangular, over 2x wider than long, widely separated. LAPs quadrangular in lateral view ( Fig. 19a–b View FIGURE 19 ) with a notable vertical wavy ridge that separates the proximal part of the plate from the arm spine articulation area, arm spine articulations typical Ophiacantha in form. VAPs 1.5x as wide as long, contiguous, with a glassy striated convex distal margin and obtuse angle proximally ( Fig 19c View FIGURE 19 ); to 9 finely-rugose arm spines forming a fan across the dorsal arm proximally, uppermost just over 2 segments in length ( Fig. 19d View FIGURE 19 ); one oval tentacle scale, sometimes thorny at the tip, 1/3 the VAP in length.

Distribution. W Atlantic ( 305–1753 m), Indo-Pacific ( 410–1100 m), New Zealand ( 850–980 m), Atlantis Bank ( 828–994 m).

Remarks. The Atlantis Bank specimens differ from previous descriptions in having suboral as well as the 3 oral papillae. These are only rarely present on the other specimens examined. More specimens are required to determine whether this difference is significant or not. The DNA evidence ( Fig. 2b View FIGURE 2 ), however, suggests that it is a widespread species complex occurring from Western Atlantic to northern New Zealand.