Batheuchaeta lamellata is an aetideid calanoid copepod known after both sexes (female 4.70-5.20 mm and male 4.50 mm in total length). Species is mostly abyssopelagic, recorded in the Pacific, Atlantic and Indian Oceans.
Female. Total length 4.70-5.20 mm. Abdomen 4.0-4.6 times shorter than cephalothorax. Rostrum absent. Th5 lobes large, lamelliform, varying in shape; when looking ventrally visible, as reaching the last third of genital segment, when looking ventrally - equal in length, slightly longer or shorter than genital segment. They are extremely asymmetrical. Genital segment symmetrical; ventral swelling strongly prominent with rounded apex; length of genital segment more than that of 3 following segments together. Genital field asymmetrical. A1 reaching posterior end of genital segment. Ri Mx1 with 14-16 setae. Oral parts typical of the genus. Ri P1 with row of spinules along distal edge of external lobe apically. P2-P4 typical of the genus.
Male. Total length 4.50 mm. Cephalothorax 3.3 times longer than abdomen. Right Ri P5 longer than left with lateral projection, left Ri narrowed in proximal part, both Ri rounded at apex. Distal segment of right Re bears claw-like appendage at the top.
Most probably abyssopelagic species. Stenotherm and stenohaline species.
The north-western part of the Pacific Ocean, the Kurile-Kamchatka, Aleutian and Marianas Trenches area; the north-eastern Atlantic, the antarctic part of the Indian Ocean (Markhaseva, 1996), recorded in the western part of the Indian Ocean (Grice and Hulsemann, 1967).
Type locality: Kamchatka, Shipunsky Peninsula, 90 miles to SE off Shipunsky Cape (Brodsky, 1950).
57 females and 11 male from samples: 1, 9, 19, 69-70, 85-86, 97, 102, 104-105, 122, 124, 126-128, 139-140, 147, 163-164, 175-176, 181, 192-193, 197, 201, 379, 465, 474. See examined samples module.
Type Material: Lectotype, 1 female, N 39811. High latitude expedition of Arctic Scientific Institution, 25 July 1946; ice-breaker "Severny Polus"; depth of site 4600 m, stratum of sampling: 4000-0 m. Is kept in the Zoological Institute, Russian Academy of Sciences, St. Petersburg.