Breviturma pusilla ( Brock, 1888 )

O’Hara, Timothy D. & Thuy, Ben, 2025, Seamount ophiuroids from the High Seas of the western Indian Ocean, Zootaxa 5718 (1), pp. 1-88 : 59

Breviturma pusilla ( Brock, 1888)

Fig. 23

Ophiomastix pusilla Brock, 1888: 499–500 . — Koehler, 1905: 65, pl. 6(6–10), 13(3).

Ophiocoma pusilla . — Clark, H.L., 1921: 131. — Devaney, 1970: 25–28, fig. 26, 29. — Clark, A.M. & Rowe, 1971: 86–87,. — Clark, A.M. & Courtman-Stock, 1976: 174, fig. 190. — Clark, A.M., 1976: 259–260. — Cherbonnier & Guille, 1978: 173– 174, pl. 11(3–4). — Sloan, Clark & Taylor, 1979: 106. — Clark, A.M., 1980: 544. — Price & Rowe, 1996: 77. — Stöhr, 2011: 36–38, fig. 17l–m.

Ophiocoma aegyptica Soliman, 1991: 81–86 , fig. 2–6 [according to Olbers & Samyn, 2012].

Breviturma pusilla . — O’Hara et al., 2019a: 74. — Olbers et al. 2019: 169–171, fig. 162–163.

STUDY MATERIAL. — MD208 : stn WS03, Walters shoal, Zone sommitale Sud-Ouest , 33° 12.25´S, 43° 50.818´E, 40 m, 30/4/2017: 1 ( MNHN IE.2016.1340) ( DNA code= IE.2016.1340) . — MD208 : stn WB05 , Walters shoal, Zone sommitale Sud , 33° 15.12´S, 43° 54.514´E, 26–30 m, 1/5/2017: 1 ( MNHN IE.2023.4162) . — MD208 : stn WB09 , Walters shoal, Zone Sommitale Nord Ouest , 33° 13.767´S, 43° 55.7751´E, 27–30 m, 4/5/2017: 8 ( MNHN IE.2023.4165), 1 ( MNHN IE.2016.1351) . — MD208 : stn WB10 , Walters shoal, Zone Sommitale Nord Ouest , 33° 9.131´S, 43° 51.7939´E, 30 m, 6/5/2017: 2 ( MNHN IE.2016.1352) .

COMPARATIVE MATERIAL EXAMINED. Breviturma pusilla ( Brock, 1888) : BIOLUM/18, Lizard Is, Coconut Beach, 14° 40.8´S, 145° 28.5´E, 2–5 m, 25/10/2005 , MV F109823 ( DNA code=F109823) . SAYA / YB01 , NE Saya de Malha, 10° 22.75´S, 62° 7.75´E, 24 m, 10/11/2022, MNHN IE.2023.4347 ( DNA code=IE.2023.4347).

Distribution. W Indian Ocean ( 0–70 m), E Indo-W Pacific ( 0–120 m), S Africa ( 11–20 m), Lord Howe Island ( 4–21 m), Walters Shoal ( 26–40 m).

Remarks. These diminutive specimens (maximum 7 mm dd) are identifiable as B. pusilla , having relatively narrow dorsal arm plates, hollow non-alternating arm spines, 3–4 oral papillae and lacking granules near the radial shields ( Devaney 1970). The single Indo-Pacific DNA sample we have sequenced is sister to both Indian Ocean samples. Sibling species are common across the Indian Ocean, including in the Ophiocomidae ( Boissin et al. 2017; O’Hara et al. 2019a), but more samples are required before species boundaries can be defined in this instance. The name B. aegyptica ( type locality Red Sea) is available if all Indian Ocean specimens prove to be conspecific. Breviturma pusilla is a shallow water species and historical records below 100 m need to be verified.

Figures

FIGURE 23. Breviturma cf. pusilla MNHN IE.2023.4165 (a) dorsal, (b) ventral, (c) whole body, (d) lateral arm base.