Leucon argentinensis Mühlenhardt-Siegel, 2025Holotype.South Atlantic Ocean • ovig. ♀; Argentine Basin; DIVA III exped. FS Meteor; stat. M 79 / 1-533; 36°0.20'S, 49°01.96'W [- 36.00333, - 49.03267; - 36.00450, - 49.03533]; 4602 [4601.8–4605.7] m depth; 15 July 2009; Pedro Martínez Arbizu leg.; epibenthic sledge; ZMH -K-064950.Paratypes.* • 64 subA. ♂♂ + 94 ovig. ♀♀; same data as holotype; one female dissected; ZMH -K-064951. * • ♂; Argentine Basin; DIVA III exped. FS Meteor; stat. M 79 / 1-534; 36°0.61'S, 49°01.54'W [- 36.01017, - 49.02567; - 36.01150, - 49.02900]; 4608 [4607.8–4605.1] m depth; 16 July 2009; Pedro Martínez Arbizu leg.; epibenthic sledge; ZMH -K-064952. * • 19 m. + ♂ + 53 subA. ♂♂ + 61 non-ovig. ♀♀ + 9 prep. ♀♀ + 7 ovig. ♀♀; Argentine Basin, DIVA III exped., FS Meteor stat. M 79 / 1-532; 35°59.16'S, 49°0.75'W [- 35.986, - 49.0125; - 35.98733, - 49.01483]; 4605 [4604.5–4605.4] m depth; 15 July 2009; Pedro Martínez Arbizu leg.; epibenthic sledge; one male dried out, 9 damaged carapaces are included; ZMH -K-064978. * • 111 m. + 412 non-ovig. ♀♀; same data as holotype; 18 carapaces are included; ZMH -K-064979. * • 22 juv. + 30 m. + subA. 100 ♂♂ + 320 ovig. ♀♀ + 314 non-ovig. ♀♀; same data as ZMH -K-064952; 149 damaged carapaces / specimens are included; ZMH -K-064980.Diagnosis.Carapace with dorsomedian line serrate (17 teeth) to the hind margin. Antennal notch with small extra tooth in sinus, sinus reaching beyond level of frontal lobe anterior margin. Antenna 1 rather stout, peduncle articles almost equal in length; (after Mühlenhardt-Siegel 2025).Distribution.Southwest Atlantic, Argentine Basin, 4602–4608 m depth.