Boeck, 1872
Short description:
Aetideopsis armata is an aetideid calanoid copepod known after both sexes (female 3.28-4.50 mm and male 3.28-4.00 mm). The species is widespread in the northern part of the Atlantic Ocean, in the Mediterranean and Adriatic seas, in the Indian Ocean and the Pacific Ocean. Most probably meso-bathypelagic species.
Taxonomic description:
Female. Total length 3.28-4.50 mm. Cephalothorax 3-3.8 times longer than abdomen. Crest absent. Rostrum very small, rather smaller than in other species of the genus, its rami spaced close to each other. Th5 points reaching or exceeding the middle of genital segment (dorsal view). A1 extending posterior border of Abd2. Re A2 lacking medial seta [Tanaka and Omori (1970a) mentioned such seta in their specimens]. Ri2 Md with 10 (8 terminal and 2 posterior) setae. Mxp protopodite lacking projection. P1 with external spines at Re1 and Re2 reaching or slightly exceeding base of next spine. P2 with incomplete separation of Ri into 2 joints, external spines at Re3 P2 short, not reaching base of following spine, terminal spines at Re3 P2 with about 32 denticles. P3-P4 with 3-jointed rami.
Male. (Description after Sars (1903) and Park (1975c)). Total length 3.28-4.0 mm. Rostrum similar to that in female. Segmentation as that in female. Points of Th5 somewhat not reaching posterior border of Abd1. A1 reaching Th3. Oral parts rudimental in comparison with female. P1-P4 as in female, only external spines at Re P1 shorter than in female. P5 typical of the genus, at left Re3 apically there is small terminal spine and 2 thin little spines.
Vertical distribution:
Species was found in samples collected by closing nets from meso- and bathypelagial (Farran, 1908; Jespersen, 1934; Lysholm, Nordgaard and Wiborg, 1945; Park, 1975c; Roe, 1984), found at the depth 240 m near bottom (Matthews, 1964), also in epipelagial (Wilson, 1950; Vervoort, 1963). Also found in total hauls from depths above 3000 m (Sars, 1925, etc.)
Geographical distribution:
Widespread in the northern part of the Atlantic Ocean: to the north till 75°N in Baffin Bay (Jespersen, 1934) and the Barents Sea (Vervoort, 1952b), to the south till the Gulf of Guinea (Vervoort, 1963), also found in the Gulf of Mexico and the Caribbean Sea (Park, 1970, 1975c), in the Mediterranean and Adriatic seas (Rose, 1937), to south off equator in Atlantic was not found; for the first time recorded in the north-western part of the Indian Ocean; in the Pacific Ocean occurs rarely: the most nothern finding - in the north-western part in the Izu region (Tanaka and Omori, 1970a), the most southern - of the region of 36°S in the eastern part (Markhaseva, 1996), also recorded from the tropical part of the Pacific Ocean (Wilson, 1950). K.A. Brodsky recorded A. armata (= P. armatus ) for the central part of the Arctic Ocean: region of 78°N 166-168°W (Brodsky, 1950; Brodsky and Nikitin, 1955), but in our collections from this region species was not found.
Type locality: the western coast of Norway (1901).
Material examined:
5 females from samples : 361, 368, 403, 441, 442. See examined samples module.