(Fig. 7A)
Sergestes tenuiremis Kröyer, 1855: 30. — Illig 1927: 283, figs. 6–10.
Sergestes kroyeri Bate, 1881: 193.
Sergia kroyeri. — Krygier & Wasmer 1988: 72. — Hendrickx & Estrada-Navarrete 1989: 110.
Sergia tenuiremis. — Pearcy & Forss 1966: 1137. — Walters 1976: 823. — Butler 1980: 49. — Krygier & Pearcy 1981: 75. — Pérez-Farfante & Kensley 1997: 200.
Diagnosis (after Butler 1980). Body slender and compressed. Rostrum short, barely projecting beyond frontal margin, with apex blunt to acute, at times with small tooth on posterior dorsal surface. Carapace with lateral carina extending from branchiostegal to hepatic region, suprabranchial carina extending almost to posterior margin, sometimes branching ventrally and posteriorly above ventral margin of carapace, cervical sulcus conspicuous. Ventral margin of carapace concave. Eye moderately large, cornea well developed, with tubercle on inner margin of stalk. Peduncle of first antenna exceeding scaphocerite, stout, dorsal tubercle on first segment. Stylocerite short. Scaphocerite narrow, lateral tooth exceeding blade, basicerite with upper rounded lobe. Third maxilliped with setae on propodus, dactyl; dactyl with about 8 short, tapering segments. Pereopod 1 shorter than third maxilliped, slender, propodus and dactyl with setae on both margins, dactyl with 1 or 2 distal setae. Pereopod 2 slender but longer than first, propodus slender, with about 13 segments, minutely chelate. Pereopod 3 slightly longer than second, slender, propodus with setae, about 12 segments, minutely chelate. Pereopod 4 shorter than third, slender, with setae, propodus with blunt apex, no dactyl. Pereopod 5 shorter than pereopod 4, as slender, setose; propodus with blunt apex, no dactyl. Abdominal somite 1 with oblique lateral carina, somite 2 with short lateral carina, faint transverse sulcus, somite 3 with dorsoventral carina, transverse sulcus; somite 4 with v-shaped sulcus, somite 5 with arched lateral carina, oblique sulcus; somite 6 with dorsal posterior spine with slight carina, lateral carina, carina along ventral margin. Telson shorter than uropods, narrowing, with acute apex, 2 or 3 pairs dorsal spines, apex of inner uropod not reaching distolateral spine of outer uropod. Male total length about 63 mm, female 75 mm.
Color in life. Vermillion, darker red over most of telson and uropods.
Habitat and depth. Pelagic, 570–1000 m. Walters (1976) reported that off the Hawaiian Is., immature shrimp (carapace length less than 15 mm) were vertical migrators but most of the adults remained below 800 m.
Range. Northeast of New Zealand, Hawaiian Is., west coast of Vancouver I., off Oregon south to off Point Loma Light, San Diego County, California (Velero IV sta. 10996-66, LACM), Atlantic and Indian oceans. Type locality Greenland.