Brodsky, 1950
Short Description:
Gaetanus brevirostris is an aetideid calanoid copepod known after both sexes (female 4.00-4.20 mm and male 4.0 mm in length) from the northern part of the Pacific Ocean, mainly bathypelagic.
Taxonomic Description:
Female. Total length 4.00-4.20 mm. Cephalothorax about 3 times longer than abdomen. Frontal spine absent. Spines on Th5 posterior corners short, situated in the middle of posterior Th5 border (lateral view). A1 as long as cephalothorax, or longer by 1-2 segments. Re1 A2 lacking setae. Re2 A2 with 2 setae. Md palp base with 2, Ri1 Md with 2, Ri2 Md with 9 terminal setae. Second Mx1 internal lobe with 4 setae, Ri with 14 setae. Lateral plate on Mxp protopodite absent. P1 with 3-segmented Re, Re1 P1 lacking external spine, spine on Re2 P1 exceeding the midlength of the next segment. P4 coxopodite with 19-28 spines.
Male. Total length 4.0 mm. Frontal spine absent. Spines on posterior Th5 corners shorter than Abd1. Right Re3 not bilobated, but stylet-like.
Vertical distribution:
The species was found in the hauls with known sampling ranges from bathypelagic - upper abyssopelagic (Markhaseva, 1996).
Geographical distribution:
Pacific Ocean: the north-western part, the Kurile-Kamchatka Trench region, the region of Aleutian Trench (Brodsky, 1950; Markhaseva, 1996).
Type locality: the north-western part of the Pacific Ocean (Brodsky, 1950).
Material examined:
More than 10 females from samples: 63-65, 81, 126, 138, 161, 193, 196. See examined samples module.
Lectotype: 1 female, N 39805, 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.