Giesbrecht, 1892
Short Description:
Chiridius poppei is an aetideid calanoid copepod known after both sexes (female 1.59-2.20 mm and male 1.50-1.58 mm in length). Species occurs in the Atlantic, Pacific and Indian oceans. Epi-mesopelagic species.
Taxonomic Description:
Female. Total length 1.59-2.20 mm. Cephalothorax 2.7-3.2 times longer than abdomen. Posterior points of Th5 corners reaching, or slightly exceeding the midlength of genital segment. A1 nearly as long as cephalothorax, or reaching the posterior edge of genital segment - posterior edge of Abd2. Ri2 Md with 9 terminal setae. Re Mx1 with 8 setae. External spines on Re1 and Re2 P1 shorter than in other species of genus, not reaching the base of following spine. P2 with 3-segmented Re (in specimens examined separation between Re1 and Re2 incomplete) and Ri one-segmented (with traces of separation) reaching the line of division of Re2 and Re3 P2. External spines on Re3 P2 short, not reaching the base of following spine, terminal spine with 23-27 denticles. P3 and P4 with 3-segmented rami, terminal spines with 24-26 denticles.
Male. (Description after Tanaka (1957a) and Park (1975a) with modifications). Total length 1.50-1.58 mm. Cephalothorax 2.5-2.7 times longer than abdomen. Th5 points reaching the midlength of Abd1. A1 reaching the posterior border of Abd1, or posterior edge of Abd2. Setae on the base of A2 and Ri1, Md of less size than in female. On the Md palp base 1 seta. Ri2 Md with 9 setae. Mx1 with 1 seta on the third internal lobe, 3 setae on protopodite near Ri base, 8 on Ri (Tanaka noted 9 setae), 9 setae on Re and 6 (7 mentioned by Tanaka) on external lobe. Ri1 Mxp with 3 setae in its middle part, 2 of which very short and small. External spines on Re1 and Re2 P1 shorter and thinner than in female. P2 with more visible separation between Ri segments than in female, in other features it is like in female, terminal spine with 27 denticles. P3 and P4 with 3-segmented rami, terminal spines with 25 and 20 denticles respectively. P5 of almost the same length.
Vertical distribution:
The species was found in series of hauls in mesopelagic (Lysholm, Nordgaard and Wiborg, 1945; Tanaka, 1957a; Bradford and Jillett, 1980), also recorded from epipelagic (Vervoort, 1963; Grice, 1962; Chahsavar-Archard, C. and Razouls, 1982; Roe 1984; etc.), and also in total hauls from depths of few km.
Geographical distribution:
Species found in the Atlantic, Pacific and Indian Oceans. The most northern locality in the Atlantic Ocean in the Strait of Davis (Jespersen, 1934), the most southern, in the Gulf of Guinea (Vervoort, 1963). In the Gulf of Mexico (Park, 1975a), in the region of Florida (Owre, 1962), the Mediterranean and Adriatic seas (Giesbrecht, 1892; Sars, 1925; Hure, 1955), in the Indian Ocean (Grice and Hulsemann, 1967, Markhaseva, 1996), in the Pacific Ocean in the region of Marianas Trench (Markhaseva, 1996), the most northern finding in the Pacific Ocean: the Izu region (Tanaka and Omori, 1970a), the most southern: near the coast of South America (45°01'S 76°33'W) (Bjornberg, 1973), near New Zealand (Bradford and Jillett, 1980; Markhaseva, 1996), in the tropical Pacific, in the Malay Archipelago region (A. Scott, 1909).
Type locality: the Mediterranean Sea (Giesbrecht, 1892).
Material examined:
16 females from samples: 202, 360, 367, 386, 399, 575. See examined samples module.