Species Card of Copepod
Calanoida ( Order )
    Diaptomoidea ( Superfamily )
        Acartiidae ( Family )
            Acartia ( Genus )
                Euacartia ( Sub-Genus )
Acartia (Euacartia) southwelli  Sewell, 1914   (F,M)
Sewell, 1914 a (p.244, figs.F,M); Steuer, 1923 (p.14, figs.F,M); Sewell, 1924 (p.790, fig.F); 1932 (p.393, Rem.); 1948 (p.324, Rem.); Kasturirangan, 1963 (p.64, figs.F,M); Abraham, 1970 (p.52, Rem.); Silas, 1972 (p.650); Goswami & Goswami, 1978 (p.111, figs.); Madhupratap & Haridas, 1994 (p.67, Redescr., figs.F,M); Barthélémy, 1999 (p.858, 864, figs.F); 1999 a (p.9, Fig.26, A-E); Soh & al., 2013 (p.718, Rem.p.723, Table 1, 2, fig.7, 9: chart)
Species Acartia (Euacartia) southwelli - Plate 1 of morphological figuresissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.69, Fig.1]
Female: A, habitus (dorsal view); B, urosome (dorsal), (spinules show variability); C, urosome (right lateral side); D, head with rostral filaments (ventral).
Male: F, urosome (dorsal).

Species Acartia (Euacartia) southwelli - Plate 2 of morphological figuresissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.71, Fig.3].
Female: A, A2; B, Md; C, Mx1; E, Mxp.

Species Acartia (Euacartia) southwelli - Plate 3 of morphological figuresissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.72, Fig.4].
Female: A-D, swimming legs 1-4 (respectively).

Species Acartia (Euacartia) southwelli - Plate 4 of morphological figuresissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.70, Fig.2].
Female: A, A1 (proximal segments, middle segments and distal segments, respectively);
Male: right A1 (proximal segments, middle segments and distal segments, respectively); C, segment 14 of right A1.

Species Acartia (Euacartia) southwelli - Plate 5 of morphological figuresissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.73, Fig.5].
Female: A, P5.
Male: B, P5.

Species Acartia (Euacartia) southwelli - Plate 6 of morphological figuresIssued from : R.B.S. Sewell in Spolia Zeylanica, 1914, 9. [Pl.XIX, Figs.8-9].
Female (from Gulf of Mannar): 9, P5.
Nota: Head and 1st thoracic segment separate, 4th and 5th fused. Posterior thoracic margin rounded and devoid of spines. Forehead with a pair of slender curved rostral filaments. Proportional lengths of prosome and urosome 35:1. Proportional lengths of urosomites and furca 26:13:10:15; all segments devoid of any spines. Caudal rami nearly as wide as long (9:10). A1 20-segmented (segments 2-4, 5-6, 7-8, 9-10 fused) reach just beyond the posterior thoracic margin. P5 consist of a fairly long basal segment bearing 1 minute seta on its external margin distally, and having a long and delicate terminal spine, this spine is curved and has a markedly swollen base.

Male: 8, P5.
Nota: Proportional lengths of prosome and urosome 4:1. Proportional lengths of urosomites and furca 18:14:3:9:10. Right A1 15-segmented (segments 1-4, 5-6, 7-8, 19-21, 22-25 fused) modified to form a grasping organ. P5: the right leg forms a claw, the 2nd segment bears a somewhat quadrangular process on its inner border, and the 3rd segment terminates in 2 short unequal spines.

Species Acartia (Euacartia) southwelli - Plate 7 of morphological figuresissued from : R.B.S. Sewell in Fauna of the Chilka Lake, 1924, 12. [Pl. XLV, Fig.6].
Female and Male (from Chilka Lake).

Species Acartia (Euacartia) southwelli - Plate 8 of morphological figuresissued from : R.-M. Bathélémy in J. Mar. Biol. Ass. U.K., 1999, 79. [p.864, Fig.7, A].
Scanning electon miccrograph. Female from Indian Ocean): A, genital double-somite (ventral); Note the epicuticule (arrowheads) covering the genital slits except the copulatory field (arrows).
Scale bar: 0.020 mm.

Species Acartia (Euacartia) southwelli - Plate 9 of morphological figuresIssued from : H.Y. Soh, S.Y. Moon, E.O. Park & B.A.V. Maran in J. Crustacean Biol., 2013, 33 (5). [p.727, Table 1].
Comparison of morphological features between A. forticrusa and its congeners A. southwelli and A. sarojus

Compl. Ref.:
Patel, 1975 (p.660); Ohtsuka & al., 1995 (p.158: Rem., 159); Madhupratap & Haridas, 1986 (p.105, tab.2); Gajbhiye & Abidi, 1993 (p.137); Godhantaraman, 1994 (tab.5, 6, 7); Mauchline, 1998 (tab.8); Madhu & al., 2007 (p.54, Table 4, abundance vs monsoon); Fernandes, 2008 (p.465, Tabl.2); Rakhesh & al., 2008 (p.154, abundance vs stations); Shanthi & Ramanibai, 2011 (p.132, Table 1); Drillet & al., 2012 (p.155, Table 1, culture); Rakhesh & al., 2013 (p.7, Table 1, abundance vs stations);
NZ: 2

Distribution map of Acartia (Euacartia) southwelli by geographical zones
Species Acartia (Euacartia) southwelli - Distribution map 2issued from : C.T. Achuthankutty, N. Ramaiah & G. Padmavati in Pelagic biogeograpgy ICoPB II. Proc. 2nd Intern. Conf. Final report of SCOR/IOC working group 93, 9-14 July 1995. Workshop Report No. 142, Unesco, 1998. [p.8, Fig.6].
Salinity ranges for A. southwelli in coastal and estuarine waters of Goa (India).
Shaded area indicates the range of higher abundance.
India ( Saurashtra coast, S, Cochin, Kerala, G. of Mannar, Sri Lanka Pearl Banks, Godavari estuary & coastal, Kakinada Bay, Chilka Lake), Bay of Bengal, China (Bohai Sea)
N: 17
(44) F: 0,773; M: 0,68; (80) F: 0,726; M: 0,712; (82) F: 0,8; M: 0,75; (186) F: 0,84-0,79; M: 0,75-0,7; {F: 0,726-0,84; M: 0,68-0,75}
Rem.: estuary-neritic. Brackish.
The dimensions seem to be correlated with the salinity.
W. Zhang confirms the occurence of this species in the China seas (in the Bohai Sea, 2010).
For Ohtsuka & al. (1995, p.158) A. southwelli, as Bestiolina similis and Pseudodiaptomus marinus belong to the Indo-West Pacific warm-water element which is thought to have derived directly from the Tethys fauna (see in Nishimura, 1981). These copepods seem prefer relatively high salinities.
Last update : 29/08/2014
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[Accessed August 31, 2014]

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