Vervoort, 1957
Short Description:
Pseudochirella mawsoni is an aetideid calanoid copepod known after both sexes (female 5.42-6.75 mm and male 5.20-5.66 mm in length) from subantarctic-antarctic zone, of mostly mesopelagic.
Taxonomic Description:
Female. Total length 5.42-6.75 mm. Cephalothorax 3.3-4.0 times longer than abdomen. Th5 posterior corners rounded. Genital segment asymmetrical: right side in its posterior part with significant projection; left one swollen in its midlength (dorsal view). Configuration of genital segment varies (already mentioned (Park, 1978)). A1 reaching the end of genital segment, or the end of caudal rami. Re1 A2 with very small seta, arranged on the knob, Re2 A2 with the distal seta only; Ri1 A2 with 1 (after Park (1978) with 2) setae. Ri1 Md with 2, Ri2 Md with 9 long terminal and 2 posterior setae. Third internal Mx1 lobe with 4 setae and sensory appendage. Mx2 and Mxp typical of the Pseudochirella . Re P1 with indistinct separation of Re1 and Re2 of 3-segmented Re. Ri P2 incompletely 2-segmented. P4 coxopodite with 6-10 spines.
Male. Total length 5.20-5.66 mm. Cephalothorax 2.6-3.3 times longer than abdomen. Cephalon and Th1, as well as Th4-Th5 completely fused. Th5 posterior corners rounded with spines on both sides (removed dorsally). A1 reaching Abd2. Oral parts in comparison with that in female reduced. Re P1 3-segmented, external spine on Re1 very small. Ri P2 indistinctly 2-segmented. P5: left Re2 with 2 teeth in the distal part of the segment, Re3 is about 2 times longer than wide.
Vertical distribution:
Mesopelagic species, found in hauls from 750-550 and 750-1000 m (Vervoort, 1957), in hauls 0-183 and 0-366 m (Bjornberg, 1973), 0-313 m (Park, 1978), 0-500 m (Grice and Hulsemann, 1968), and also in total hauls from depths of 3700 m
Geographical distribution:
The species may be characterized as subantarctic-antarctic; it is distributed circumpolar in Antarctic and Subantarctic. To the North from Antarctic Convergence species found: in the Indian Ocean in the region of 45°S (Vervoort, 1957), in the Pacific Ocean widespread along the coast of South America to 31°S (Grice and Hulsemann, 1968; Bjornberg, 1973; Markhaseva, 1996) also in the region of 40-42°S 124-144°W (Markhaseva, 1996), recorded from the New Zealand region (Bradford and Jillett, 1980).
Type locality: Antarctica (Vervoort, 1957).
Material examined:
271 females and 39 males from samples: 266-272, 274-276, 280, 283, 285, 287, 289, 290, 298, 299, 302-305, 307, 314-317, 319-324, 329, 330, 332-334, 338-343, 345-349, 353, 354, 357, 358, 363, 366, 369-371, 373, 376, 382, 384, 431, 435, 436, 447, 453. See examined samples module.