Markhaseva, 1986c
Short Description:
Pseudeuchaeta arctica is an aetideid calanoid copepod known after both sexes (female 10.30-10.50 mm and male 8.80 mm in length) from the central part of the Arctic Ocean, more probably benthopelagic species.
Taxonomic Description:
Female. Total length 10.30-10.50 mm. Cephalothorax 2.8-3.0 times longer than abdomen. Rostrum present as small rounded plate. Th5 posterior corners prolonged into not divergent points (dorsal view), directed backwards (lateral view). Genital segment is the widest in its anterior third (dorsal view). A1 reaching nearly the end of cephalothorax. A2 typical of the genus (on internal Ri2 A2 lobe 7 setae). Ri2 Md with 8 setae; otherwise setation typical of the genus. Mx1 gnathobase with 12 setae, its second and third internal lobes with 4 and 3 setae respectively, protopodite near the Ri base with 5 setae, Ri with 15 sclerotized setae, partly very strong, Re with 11 setae, external lobe with 9. Mx2 typical of the genus, setae robust, sclerotized. Mxp with digital appendage not exceeding the length of longest seta in the distal group; some part of Ri setae strongly sclerotized, supplied with minute crescent-like bodies. Re1 P1 lacking external spine. P2-P4 typical of the genus.
Male. Total length 8.80 mm. Cephalon and Th1 fused, line of Th4-Th5 fusion visible. Cephalothorax 3.1 times longer than abdomen. Th5 posterior corners slightly prolonged (dorsal view). Abd2 is the longest among abdominal segment. Abd 2-4 supplied with thin spinules along posterior border. Length and width of caudal rami nearly equal. A1 nearly as long as cephalothorax. Ri A2 1.7 times longer than Re, Ri2 A2 with 12 setae; coxopodite and basipodite with 1 seta each, Re1 A2 lacking seta, Re2 A2 with 1 short seta, Re3-Re6 with long setae, Re7 with 3 terminal setae. Md palp base and Ri1 Md without setae, Ri2 Md with 8 setae. Mx1 with 1 seta on second internal lobe, 2 setae on third internal lobe, 4 setae on protopodite near the Ri base, 12 setae on Ri, 10(?) on Re, 6 setae on external lobe. Mx2 strongly reduced. Mxp protopodite setation reduced. Digital appendage was not seen. Swimming legs as in female. P5 biramous, left and right legs with 3-segmented Re and one-segmented Ri. Terminal left Re3 segment with 2 spines, with short thick spinules, together with setae along its internal side.
Vertical distribution:
The species was found in trap to trawl hauls from depths 3300-3500 m. Very possibly benthopelagic species.
Geographical distribution:
Eastern sector of the central part of the Arctic Basin.
Type locality: 81°42'N 126°70'W.
Material examined:
2 females and 2 males from samples 561, 562. See examined samples module.
Holotype: female, N 1/64697; "SP-22", 81°42'N 126°07'W; 11 June 1977; depth 3500 m.
Paratypes: 1 female and 1 male, N 2/64698; "SP-22", 79°26'N 137°39'W; 2 August 1977; depth 3290m.