Oneirophanta mutabilis Théel, 1879 — $ Gebruk 2008: 50, 51.
Type locality: Between Marion and Crozet Islands (46°46’S, 45°31’E).
See: Théel (1879: 6–7, pl. 1, figs. 4–6); Hansen (1975: 24–32, figs. 2–5).
Occurrence: cosmopolitan, in the Atlantic, Pacific, Indian and Southern Oceans; from the Rockall Trough (Gage et al. 1985) south to the waters between the Azores and the Iberian Peninsula (Hérouard 1923, Gebruk 2008); reported elsewhere off Uruguay, South Atlantic (36°44’S, 46°16’W; Théel 1882); O. mutabilis affinis Ludwig, 1893 is restricted to the East Pacific (Hansen 1975).
Depth: 1,804 –6,000 m (Hérouard 1923, Tyler et al. 1985a), mostly deeper than 3,200 (Gage et al. 1985); AZO: 2,954 –3,050 m (Gebruk 2008).
Habitat: epibenthic on soft sediments, from sandy clay to ooze (Hansen 1975).
Larval stage: possibly direct or lecithotrophic (Tyler et al. 1985a).
Remarks: historically, the cosmopolitan Oneirophanta mutabilis mutabilis was recorded in the waters near the Azores, between the archipelago and the European continental shores (e.g., Perrier 1902, as Oneirophanta mutabilis). Recently, Gebruk (2008) reported this species within the archipelago waters (G.O. Sars, MAR–ECO cruise, sta 40/367: 42°55’N, 30°20’W, 2,954 –2,968 m; sta 46/372: 42°46’N, 29°16’W, 3,005 –3,050 m). The somehow discontinuous distribution of this cosmopolitan species in the Atlantic may reflect an artefact produced by insufficient sampling as a consequence of the great depths in which the species is usually found.