Astrotoma cf. manilense, IN, 2018

O’Hara, Timothy D. & Thuy, Ben, 2025, Seamount ophiuroids from the High Seas of the western Indian Ocean, Zootaxa 5718 (1), pp. 1-88 : 16-17

Astrotoma cf. manilense

Fig. 4a – h

Astrotoma drachi . — McKnight, 2000: 68, fig. 33, pl. 32. — Okanishi & Fujita, 2013: 569. — Jossart et al., 2019: 622 – 631 [Non Astrotoma drachi Guille A, 1979 ].

Astrotoma manilense . — O’Hara & Harding, 2014: 135 – 136 .

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 2025.28 ) ( DNA code= JC066-951 ) .

COMPARATIVE MATERIAL EXAMINED. Astrotoma agassizii .I US AMLR-09/103-77, South Orkney Islands, 62° 35.23´S, 53° 46.37´W to 62° 33.8´S, 53° 49.19´W, 745 – 711 m, 5/3/2009 , MV F168816 ( DNA codes= TOH _1054, F168816). Astrotoma cf. manilense IN2018 _ V06 /070, Flat Matsuyker , 44° 9.438´S, 146° 10.26´E to 44° 9.474´S, 146° 9´E, 1218 – 1223 m, 3/12/2018 , MV F315387 ( DNA code= IN2018 _ V06 _70_2). Marion Toothfish Survey / T35 , between Prince Edward and Marion Island, 46° 44.6´S, 38° 4´E to 46° 43.6´S, 37° 45.4´E, 298 m, 24/4/2001 , SAMC MB-A83260 ( DNA code= A83260 ) .

Distribution. S America ( 201 – 309 m), Kerguelen ( 20 – 838 m), S Australia ( 391 – 1223 m), New Zealand ( 1036 – 1402 m), Antarctic ( 1559 – 1680 m), Coral Seamount ( 1186 m).

Remarks. COI for the 15 mm dd NHMUK 2025.28 sample clusters within the Astrotoma agassizii clade II of Jossart et al. (2019), within which they also included specimens from New Zealand identified by McKnight (2000) as A. drachi . O’Hara & Harding (2014) had previously placed New Zealand and Southern Australian specimens into A. manilense Döderlein, 1927 a name that has priority over A. drachi . However, without DNA from specimens around their type localities off the Philippines, it is unclear whether either of these poorly known tropical species are really the same as Jossart et al. ’s clade II that occurs across southern subpolar and temperate regions (but not Antarctica). In the interim, we use the unofficial name Astrotoma cf. manilense for this clade, which is genetically distinct from all other Astrotoma agassizii clades ( Jossart et al., 2019).

We isolated some internal arm ossicles for SEM. The vertebrae are streptospondylous ( Fig. 4d ). The LAPs ( Fig. 4e – f ) are ventrolateral in position, meeting mid-radially, enlarged abradially to support arm spines. There are 2 – 3 simple hollow arm spine articulations and 1 – 2 cylindrical pedicels that support the most ventral hooklets. A small oval VAP occurs distal to the LAP pair, not contiguous with succeeding LAPs. A row of quadrangular hooklet base plates ( Fig. 4g ) extend across the lateral and dorsal arm surfaces, with 5 – 8 ovoid-shaped hooklet pedicels on each plate. These are more regularly placed than in A. agassizii (see Turner et al. 2021, fig. 17f). Arm spines 2 – 3, flat, rising to 1 – 2 apices, often thorny at tip ( Fig. 4h ).

Figures

FIGURE 4. Astrotoma cf. manilense NHMUK 2025.28 (a) dorsal disc, (b) ventral disc, (c) arm base, lateral view, (d) vertebra distal view, (e) lateral arm plate from mid arm ventral view, the upper flatter section is orientated towards the ventral mid arm, the cylindrical boss supports the ventralmost hooklet (f) lateral arm plate interior view, (g) lateral arm hooklet plate, (h) arm spine.