With, 1915
Short Description:
Euchirella bitumida is an aetideid calanoid copepod known after both sexes (female 4.70-7.10 mm and male 4.80-6.10 mm in length) from the Atlantic and Pacific oceans from epi- and meso-bathypelagic.
Taxonomic Description:
Female. Total length 4.70-7.10 mm. Cephalothorax about 4.4-5.0 longer than abdomen. Crest present, like high triangular-rounded plate (lateral view). Rostrum short, robust. Th5 posterior corners slightly rectangular (dorsal view). Genital segment asymmetrical with projections on the left and on the right (dorsal view). A1 reaching nearly the end of abdomen. Ri A2 is more than one third of Re length. Ri1 A2 with 1, Ri2 A2 with 6 setae on each lobe, coxo and basipodite with 1 seta each. Md palp base and Ri1 Md without setae, Ri2 Md with 7 setae. Mx1 gnathobase with 3 setae on posterior surface, second and third internal lobes with 4 and 2 setae respectively; protopodite with 3 setae at the Ri base, Ri with 4 (after Park (1976b) with 5 setea), Re with 11 and external lobe with 8 setae. Mx2 and Mxp typical of the genus. First external spine on Re P1 exceeding the midlength of the second one. P4 coxopodite with 1 robust spine. Terminal P2-P4 spines with about 20 denticles.
Male. (Description after Tanaka and Omori (1969) and Bradford and Jillett (1980) with modifications). Total length 4.80-6.10 mm. Cephalothorax less than 4 times longer than abdomen. Cephalon with crest lower than in female, of more or less triangular shape (lateral view). Rostrum nearly as in female. Abd 2-4 supplied with thin denticles along posterior border. A1 reaching the end, or exceeding the end of caudal rami. Ri2 A2 with 6 setae on external and internal lobes. Ri2 Md with 8 setae. Mx1 in comparison with that in female rudimentary, Ri with 10 setae, external lobe with 6 (after Bradford and Jillett (1980) with 7) setae. Mx2 rudimentary. First 2 spines on Re P1 strongly rudimentary. Left Re P5 exceeding the first thickening on right Ri. Left Ri very small, Re3 with tongs, configuration varying depending of view. Right P5 with Ri slightly shorter than Re, the latter with denticles in its distal part.
Vertical distribution:
The species was found in hauls from epipelagic (Bradford and Jillett, 1980) and meso- bathypelagic (With, 1915; Park, 1976), after last author species occurs during night time in upper 100 m. It was also recorded in total haul from 700-2000 m.
Geographical distribution:
Species widespread in the Atlantic: to 63°N to the North (Jespersen, 1940) and nearly to equator to the South (Vervoort, 1963). In the Pacific Ocean to 52°N (Tanaka and Omori, 1969a, b) to the North, and to New Zealand (Bradford and Jillett, 1980) to the South, also in the region of the Malay Archipelago (Vervoort, 1963).
Type locality: the Norwegian Sea (With, 1915).
Material examined:
2 females from samples: 455, 574. See examined samples module.