Halacarus prolongatus Bartsch, 1996

Type material: Holotype deposited at the MNHN (Bartsch 1996); Paratype: One female (Bartsch 1996), IFREMER 58496 (GBIF 2022).

Type locality: Portugal: Azores Archipelago: Vent Field Menez-Gwen, Azores Triple Junction, 37º50.46′N, 32º31.35′W (Bartsch 1996; GBIF 2022).

Geographical distribution: Portugal: Azores Archipelago (Bartsch 1996; GBIF 2022).

Distribution in Portugal: Azores Archipelago: Vent Field Menez-Gwen, Azores Triple Junction (Bartsch 1996).

Ecological notes: Typical marine benthic, found from depth 840 to 870 m, hydrothermal vent associated with hydrozoans, polychaetes, molluscs and crustaceans; legs fouled with black particles and filamentous bacteria (Bartsch 1996).