Grice and Hulsemann, 1967
Short description:
Aetideopsis retusa is an aetideid calanoid copepod known after both sexes (female 1.96-2.80 mm and male 2.25-2.70 mm in total length). The species is bathy-abyssopelagic, recorded from the Atlantic, Indian and Pacific oceans.
Taxonomic description:
Female. Total length 1.96-2.80 mm. Cephalothorax 3.2-3.7 times longer than abdomen. Rostrum with robust, divergent, widely spaced at their base rami. Crest absent. Points of Th5 posterior corners reaching the midlength of genital segment (dorsal view). Distal part of spermatheca rounded, medial part rather narrowed. A1 about same length as body, sometimes slightly longer. Re1 A2 lacking setae, at Re2 A2 with 2 setae, one of which medial; Ri1 A2 with 2 setae. Ri2 Md with 9 (8 terminal and 1 posterior) setae. Proximal part of Mxp protopodite with slender projection covered with spinules. P1 with external spines at Re1 and Re2, exceeding the base of next spine. P2 with incompletely separated Ri1 and Ri2. P3-P4 with 3-jointed rami.
Male. Total length 2.25-2.70 mm. Cephalothorax 2.7-2.8 times longer than abdomen. A1 23-jointed, reaching Th4 (?). Rostral rami spaced more close than that in female, points of Th5 posterior corners longer than genital segment (dorsal view). Oral parts rudimental. P1-P4 as in female. P5 virtually not distinguished from that of A. rostrata.
Vertical distribution:
In the Indian Ocean found in tow 1020-1970 m. In the Kurile-Kamchatka Trench region in hauls taken by closing nets between 2000 and 6000 m, more often in depth range 3000-4000 m. In tows 4300-7070 m and 5065-7140 m of the region of the Aleutian Trench. Probably abyssopelagic species, but may be recorded in lower bathypelagial.
Geographical distribution:
Known of the north-western part of the Atlantic Ocean: region 37°N 69°W (Wheeler, 1970), the north-western part of the Indian Ocean (Grice and Hulsemann, 1967) and from the regions of the Kurile-Kamchatka and Aleutian trenchs (Markhaseva, 1996).
Type locality: 10°07'S 64°27'E (Grice and Hulsemann, 1967).
Material examined:
59 females and 8 males from samples: 21, 68, 82, 83, 85, 86, 97-100, 102, 121-124, 139, 147-149, 163-165, 175, 176, 180, 193, 197, 198. See examined samples module.