Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Scolecitrichidae ( Family )
            Scaphocalanus ( Genus )
Scaphocalanus impar  (Wolfenden, 1911)   (F)
Syn.: Amallophora impar Wolfenden, 1911 (p.263, Descr.F, figs.F); Bradford & al., 1983 (p.93);
? Scaphocalanus minuta Tanaka, 1937 (p.262, Descr.M, figs.M); 1961 a (p.169, Rem.); Morioka, 1972 a (p.314); Park, 1982 (p.77);
? Scaphocalanus minutus : Brodsky, 1950 (1967) (p.256, figs.M); Sewell, 1948 (p.560); Bradford, 1973 (p.143); Chen Y.-Q., 1986 (p.205, Table 1: abundance %, Table 2: vertical distribution);
? Scaphocalanus impar : Tanaka, 1961 a (p.172, figs.F); 1965 (p.19)
Sewell, 1948 (p.574); Bradford, 1973 (p.143, 144); Björnberg & al., 1981 (p.637, fig.F); Park, 1982 (p.77)
Species Scaphocalanus impar - Plate 1 of morphological figuresissued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1961, IX (1). [p.172, Fig.118]. Doubtful.
Female (from Japan: Sagami Bay): a, habitus (dorsal); b, last thoracic segment and genital segment (lateral, left side); c, P2; d, P5.
- Cephalothorax and abdomen in proportional lengths 77:23.
- Last thoracic segment with obtusely rounded corner in lateral aspect.
Urosomal segments and caudal rami in proportional lenths 35 : 21 : 18 :15 : 12 = 100.
- Caudal rami longer than wide.
- Terminal spine of exopod of P2 with 23 teeth.
P5 3-segmented; distal segments with 4 spines, the marginal outer spine arises opposite to the inner marginal spine, and is about 1/3 the length of the inner distal spine, the outer distal spine is about as long as the outer marginal spine, the inner marginal spine is about 2 times as long as the outer the distal segment, and is rather coarsely serrated on the outer margin.

Compl. Ref.:
Razouls & al., 2000 (p.343, tab. 5, Appendix)
NZ: 2 + 2 doubtful

Distribution map of Scaphocalanus impar by geographical zones
Antarct. (Indian Ocean: continental), SW Atlant., ? Japan (Izu region), ? off Hokkaido, NE Pacific tropical (in Chen Y.Q., 1986)
N: 4
(10) F: 2,4; (108) F: 2,45; {F: 2,40-2,45}
Rem.: Bathypelagic.
Sampling depth (Antarct.) :1200 m.
Genus poorly assured but probable.
Geographical distribution uncertain.
? Cf. Scaphocalanus brevicornis and Scaphocalanus farrani.
According to Tanaka (1961a, p.173) this species is closely allied to Scaphocalanus brevicornis Sars, but can be distinguished by the armature on P5 male. The present specimen has the P5 quite similar in structure to those figured by Wolfenden.
Last update : 16/11/2020
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 Any use of this site for a publication will be mentioned with the following reference :

Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2021. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed December 05, 2021]

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