Leucon longiserratus Mühlenhardt-Siegel, 2019Holotype.North Atlantic Ocean • ovig. ♀; Eastern Fracture Zone, Vema-TRANSIT exped., FS Sonne stat. SO 237-06-8; 10°22.59'N, 36°55.49'W [10.3765, - 36.92467; 10.37733, - 36.92317]; 5119–5127 [5117.3–5114.3] m depth; 02 January 2015; Nils Brenke leg.; epibenthic sledge; ZMH -K-046076.Paratypes.* • 2 m. + prep. ♀ + ovig. ♀; same data as holotype; ZMH -K-046077. * • prep. ♀; Puerto Rico Trench, Vema-TRANSIT exped., FS Sonne stat. SO 237-14-1; 19°02.08'N, 67°09.44'W [19.03467, - 67.15733; 19.03517, - 67.157]; 4552 [4918.9–4921.1] m depth; 24 January 2015; Nils Brenke leg.; epibenthic sledge; specimen dissected mounted on a permanent slide; ZMH -K-046078. * • prep. ♀; same data as ZMH -K-046078; ZMH -K-046079.Diagnosis.Carapace with long serrated dorsomedial line, 5 lateral teeth below frontal lobe; pseudorostral lobes with 8 teeth dorsally and 4 teeth ventrally. Uropod, exopod almost as long as endopod; endopod basal article more than twice as long as distal article, with microserrate cuspidate seta, second article with 5 teeth and 1 microserrate cuspidate seta (after Mühlenhardt-Siegel 2019).Distribution.North Atlantic, Vema Fracture Zone, 4552–5127 m depth.