Sars, 1905
Short Description:
Gaetanus inermis is an aetideid calanoid copepod known after female (6.20-7.35 mm in length) from the north-eastern Atlantic, the south-eastern and north-western Pacific, mainly abyssopelagic.
Taxonomic Description:
Female. Total length 6.20-7.35 mm. Cephalothorax 4 times longer than abdomen. Frontal spine absent. Spines on Th5 posterior corners absent. A1 nearly as long as cephalothorax. Re1 A2 with 1, Re2 A2 with 3 setae. Md palp base and Ri1 Md with 2 setae each; Ri2 Md with 9 long terminal and 2 small posterior setae. Second Mx1 internal lobe with 5 setae, third with 4 setae and additional teat, Ri Mx1 with 14 setae. Lateral plate on Mxp protopodite present. P1 with 3-segmented Re, with external spine on each segment, first and second external spines exceeding the distal border of Re2 and Re3. P2 with 2-segmented Ri. P4 coxopodite supplied with about 35 thin spines.
Male unknown.
Vertical distribution:
The species was found in hauls from abyssopelagic (Markhaseva, 1996) and in total hauls from 3000-6000 m.
Geographical distribution:
Atlantic Ocean: the north-eastern part (Sars, 1925). Pacific Ocean: south-eastern part (Grice and Hulsemann, 1968), off Peru (Wilson, 1950), in the north-western part of the Pacific Ocean in the Kurile-Kamchatka Trench region (Markhaseva, 1996).
Type locality: 36°46'N 26°41'W (Sars, 1925).
Material examined:
6 females from samples: 19, 83, 85, 97, 123, 163, 193. See examined samples module.