Amphiura duplicata Lyman, 1875 — $ Koehler 1896a: 208, 1896b: 244, 1898: 49–50; Grieg 1932: 37;
Ophiactis duplicata, (Lyman, 1875) — $ Koehler 1909: 171;
Amphiactis duplicata (Lyman, 1875) — Mortensen 1927a: 198;
Histampica duplicata (Lyman, 1875) — García-Diez et al. 2005: 48.
Type locality: Barbados, Caribbean.
See: Lyman (1875: 19–20, fig. 87, pl. 5, fig. 78, as Amphiura duplicata); Paterson (1985: 79, 80, fig. 32); Benavides-Serrato et al. (2011: 313–314).
Occurrence: cosmopolitan, in the Atlantic, Pacific and Indian Oceans; in the west Atlantic, from Bermuda (Lyman 1882) and Caribbean to Brazil (Downey 1969); in the East Atlantic, from the Faeroe Plateau (Tyler et al. 2005) and Reykjanes Ridge (South of Iceland; Martynov & Litvinova 2008) to North Africa (Paterson 1985) including the Azores and Cape Verde archipelagos (Koehler 1909).
Depth: 125– 2,870 m (Paterson 1985); AZO: 1,095 –2,178 m (Koehler 1909).
Habitat: hard to soft (sand or mud) substrates; can be found in association with azooxanthellate corals (Benavides-Serrato et al. 2011).
Remarks: Despite being known in the archipelago only by historical reports, Histampica duplicata appears to be common in the Azorean deep-waters as Koehler (1898, 1909) recorded this species at numerous Hirondelle and Princesse Alice stations, from depths around 1000 m to 2000 m.