Gorgonocephalus chilensis ( Philippi, 1858 )

O’Hara, Timothy D. & Thuy, Ben, 2025, Seamount ophiuroids from the High Seas of the western Indian Ocean, Zootaxa 5718 (1), pp. 1-88 : 18

Gorgonocephalus chilensis ( Philippi, 1858)

Fig. 5d – n

Astrophyton chilense Philippi, 1858: 268 .

Gorgonocephalus chilensis . — Lyman, 1882: 265. — Döderlein, 1927: 30 – 31. — Mortensen, 1936: 240 – 241. — Mortensen, 1952: 11 – 12. — Bernasconi & d’Agostino, 1977: 68 – 70, pl. 1(1 – 2). — Manso, 2010: 3, fig. 1a – c. — Olbers et al. 2019: 68 – 70, fig. 46 – 47.

STUDY MATERIAL. — JC066 : stn 4-2, Coral seamount, 41° 20.708´S, 42° 55.292´E to 41° 20.99´S, 42° 55.12´E, 1300 m, 12/11/2011: 1 ( NHMUK 2025.30 ) ( DNA code= JC066-114 ); 1 ( NHMUK 2025.29 ) .

COMPARATIVE MATERIAL EXAMINED. Gorgonocephalus chilensis ( Philippi, 1858) : PROTEKER 2/ CH 06, Baie de l’Oiseau, 48° 40.759´S, 69° 7.42´E to 48° 40.792´S, 69° 7.361´E, 93 – 105 m, 27/11/2013, MNHN IE.2013.16276 ( DNA code=TOH90-IE.2013.16276). Talud Continental 1/33, Mar del Plata Submarine Canyon, 37° 58.698´S, 55° 11.899´W, 308 m, 17/8/2012, CNP-INV ( DNA code=L33L). TAN0803/53, Seamount 5 Eltanin, Macquarie Ridge. New Zealand EEZ, 51° 2.82´S, 162° 1.13´E to 51° 3.15´S, 162° 1.48´E, 398 – 489 m, 5/4/2008, NIWA 40048 ( DNA code= NIWA 40048).

COMPARATIVE MATERIAL NOT EXAMINED. Gorgonocephalus chilensis ( Philippi, 1858) : AV17-18/ H116, Tristan da Cunha EEZ, Yakhont Sea Mount WEST, 39° 18.9´S, 8° 1.92´W, 327 m, 4/1/2018 , BAS ( DNA code= BAS008 ). Shenhalyongshi /SY013, Zhongsha Island complex seamount, 13° 58.68´N, 114° 52.09´E, 1550 m, 25/9/2020, identified by Nethupul et al. 2022a as Gorgonocephalus chilensis novaezelandiae, CAS IDSSE-EEB-SW0007 ( DNA code= MZ198761 ) .

Distribution. S America ( 6 – 1398 m), Kerguelen ( 60 – 943 m), Antarctic ( 40 – 1615 m), Tristan da Cunha ( 310 – 335 m), Coral Seamount ( 1300 m).

Remarks. The Coral Seamount specimens (40 and 55 mm dd) have tall tubercles on the disc, especially along the raised section over the radial shields, the dorsal arm surface is granular but with few tubercles, there are 3, rarely 4, arm spines, and girdle hooklets start after the 2nd arm branching. The DNA sequence of NHMUK 2025.30 is very similar to other G. chilensis specimens across the Southern Ocean, from South America to the Balleny seamounts. But it does not occur around the continent of Antarctica. The New Zealand-South China Sea specimens form a separate COI clade distinct from those of the Southern Ocean and are currently recognised as G. chilensis novaezelandiae Mortensen, 1924 (see Nethupul et al. 2022a).

Figures

FIGURE 5. (a–c) Gorgonocephalus pectinatus NHMUK 2025.31 (a) dorsal disc, (b) dorsal (whole animal), (c) lateral arm; (d–n) Gorgonocephalus chilensis NHMUK 2025.30 (d) dorsal disc, (e) dorsal (whole animal), (f) lateral arm, (g) lateral arm plate, exterior view, (h) lateral arm plate, interior view, (i) lateral arm hooklet plate, (j) dorsal arm hooklet plate, (k) distal arm spine, (l) proximal arm spine; (m) vertebra of proximal segment, distal view, (n) vertebra of distal arm segment, distal view; (o–t) Gorgonocephalus pectinatus NHMUK 2025.31 (o) vertebra, distal view, last segment before branching, (p) lateral arm plate, exterior view), (q) lateral arm plate, interior view, (r) arm hooklet plate, (s) hooklet, (t) proximal arm spine.