Wolfenden, 1904
Short description:
Aetideopsis multiserrata is an aetideid calanoid copepod known after both sexes (female 2.52-3.54 mm and male 2.70-3.25 mm in total length). The species is mostly meso-bathypelagic, occurring in the Pacific and Atlantic Oceans.
Taxonomic description:
Female. Total length 2.52-3.54 mm. Cephalothorax 3.2-3.8 times longer than abdomen. Crest poorly developed, situated at the level of A2. Rostral rami divergent (varying degree of divergence in different specimens). Species well distinguished from the other species of the genus by specific abrupt line of cephalon in front of rostrum (lateral view). Points of Th5 reaching or not reaching the midlength of genital segment (dorsal view). Position of distal part of spermatheca varying (in different degree elevated in different specimens, and not always globe-shaped). A1 reaching Abd2-3. Re2 A2 without medial seta. Ri2 Md with 10 seta. Mxp protopodite without projection. P1 with external spines at Re1 and Re2 reaching the base of next spine or exceeding it. Separation between Ri P2 joints incomplete. Segmentation of P3-P4 typical of the genus.
Male. Total length 2.70-3.25 mm. Cephalothorax 2.5-2.7 times longer than abdomen. Rostrum with closely spaced not divergent rami. Points of Th5 exceeding posterior border of genital segment (dorsal view). A1 not reaching Th4. Oral parts rudimental. Ri1 Md with 3 setae, Ri2 Md with 1, base of Md palp lacking seta. First and second internal lobes of Mx1 lacking seta, third with 2 setae, protopodite near the base of Ri with 3 setae, Ri with 10, Re with 9 (?), external lobe with 6 setae. Mxp protopodite with 1 medial and 2 distal setae; Ri1 Mxp with 3 medial setae. Distal joint of left Re P5 with terminal spine and little spine near its apex.
Vertical distribution:
The species was found in hauls in meso- more often in bathypelagial (Wolfenden, 1904; With, 1915; Grice and Hulsemann, 1965; Park, 1975a; Deevey and Brooks, 1977), in the Kurile-Kamchatka Trench in upper meso- lower bathypelagial (Markhaseva, 1996). Probably mostly mesopelagic species.
Geographical distribution:
Species occurs in the western and eastern parts of the Pacific Ocean: in north-western part up to the Bering Sea (Motoda and Minoda, 1974), in south-eastern to 66°19'S (Markhaseva, 1996). In the Atlantic Ocean widespread: in the northern hemisphere the northernmost locality 61°N (With, 1915), recorded from the Gulf of Mexico (Park, 1975a), the Bay of Biscay (Farran, 1926), the most southern locality here - the Gulf of Guinea (Vervoort, 1963), the most northern - the Straight of Davis about 62°N (Jespersen, 1934).
Type locality: the North Atlantic (Wolfenden, 1904).
Material examined:
22 females and 1 male from samples: 1, 119, 124, 127,128, 140, 145,171, 172, 174, 191, 202, 267, ?274, 343, 370, 426, 447, 449, 451, 456. See examined samples module.