Asterostegus sabineae Okanishi & Fujita, 2014

Asterostegus sp. — Okanishi & Fujita, 2013: 568.

Asterostegus sabineae Okanishi & Fujita, 2014: 4 – 9, fig. 2 – 5.

STUDY MATERIAL. — 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.2016.1360) (DNA code= IE.2016.1360) . — MD208: stn CP4901, Walters Shoal, Pentes, 33° 8.4´S, 44° 0.1199´E to 33° 9.36´S, 44° 1.2499´E, 647 – 672 m, 6/5/2017: 2 (MNHN IE.2013.17142) (DNA code= IE.2013.17142) .

COMPARATIVE MATERIAL EXAMINED. Asterostegus spinigerum (Mortensen, 1933b): MD32 /DC132, La Reunion, 20° 51.1´S, 55° 37.05´E, 510 m, 2/9/1982, MNHN IE.2013.8004 (DNA code= AB758786). MIRIKY/ CP3182, entre Nosy-bé et Banc du Leven, 12° 35.32´S, 48° 17.0202´E to 12° 35.69´S, 48° 16.1598´E, 331 – 364 m, 26/6/2009, MNHN IE.2013.5295 (DNA code=IE.2013.5295).

COMPARATIVE MATERIAL NOT EXAMINED. Asterostegus maini McKnight, 2003b: Shenhalyongshi/ SC009, South China Sea, near Xisha Islands archipelago, 16° 47.79´N, 113° 15.04´E, 602 m, 31/3/2020, identified by Nethupul et al. 2022b, CAS IDSSE-EEB-SW0076 (DNA code= OK044303). Asterostegus sabineae Okanishi & Fujita, 2014:ATIMO VATAE/CP3616, Sud Cap Sainte Marie, 26° 17´S, 45° 10´E, 409 – 473 m, 14/5/2010, holotype, MNHN IE.2018.8012 (DNA code= AB758768); identified by Okanishi & Fujita (2013) as A. maini, MNHN IE.2013.8006 (DNA code= AB758767). off west coast of Madagascar, 500 m, 2009, identified by Okanishi & Fujita (2013) as A. tuberculatus Mortensen, 1933b, NHRM 123461 (DNA code= AB758769).

Distribution. W Indian Ocean (409 – 473 m), Walters Shoal (272 – 672 m).

Remarks. The COI from these specimens cluster with sequences of O. sabineae holotype deposited on NCBI (AB758768). They are also very similar to NCBI sequences (also from the SW Indian Ocean) named as A. maini (AB758767) and A. tuberculatus (AB758769) from a study by Okanishi & Fujita (2013). Asterostegus maini is a West Pacific species, and A. tuberculatus was described from NE South Africa (Mortensen 1933b). All three NCBI COI sequences should be regarded as coming from O. sabineae, although, without more data from type localities, is unclear whether this species can be distinguished from A. tuberculatus from South African.

Sequences of another species, Astroceras spinigerum Mortensen, 1933b also cluster with Asterostegus, including one of our samples from northern Madagascar (MNHN IE.2013.5295) and another NCBI sequence (AB758786) from off Reunion Island deposited by Okanishi & Fujita (2013). All other Astroceras samples form a monophyletic clade sister to Astromorpha, Trichaster and Euryale . On the basis of this evidence, we transfer A. spinigerum to Asterostegus .