Sars, 1905
Short Description:
Gaetanus curvicornis is an aetideid calanoid copepod known after female (3.70-4.75 mm in length) from the northern part of the Atlantic, the Arabian Sea and the south-eastern part of the Pacific Ocean, meso- and bathypelagic.
Taxonomic Description:
Female. (Description after Sars (1924-25), Sewell (1947) and Vervoort (1952e) with modifications). Total length 3.70-4.75 mm. Cephalothorax 3-4 times longer than abdomen. Spines on Th5 posterior corners straight, situated in the middle of posterior border of Th5 (lateral view), covering nearly one third, or a fourth of genital segment's length. Frontal spine present, directed upward and anteriorly near its base, but its top curved to rostrum. Posterior borders of Abd2-3 lacking spinules (Sewell, 1947). A1 as long as the body, or longer by 3 last segments (Sars, 1925; Sewell, 1947). Re2 A2 with 2 first setae placed on the small projections (Sewell, 1947). Second Mx1 internal lobe with 5 setae. Lateral plate on Mxp protopodite present. P1 with 3-segmented Re supplied with external spine on each segment, and second external spine not exceeding the midlength of Re3 P1. Ri P2 2-segmented. P4 coxopodite with about 12 spines.
Male unknown.
Vertical distribution:
The species was found in hauls from meso- and meso-bathypelagial (Deevey and Brooks, 1977; Vives, 1982), in total hauls from 1500-5700 m.
Geographical distribution:
The North Atlantic: noted off the region of the Azores Islands and between these Islands and near the coasts of Spain and Portugal, from the region of Madeira, the Sargasso Sea (Sars, 1925; Jespersen, 1934; Deevey and Brooks, 1977; Vives, 1982). To the North to the Baffin Bay and the west of Greenland (Jespersen, 1934). In the Indian Ocean: recorded in the Arabian Sea (Sewell, 1947); and in the south-eastern part of the Pacific Ocean in the region of 38°S (Bjornberg, 1973).
Type locality: 36°46'N 26°41'W (Sars, 1925).
Material examined:
The species absent in the collections of the Zoological Institute, Russian Academy of Sciences, St. Petersburg.