Fiche d'espèce de Copépode
Calanoida ( Ordre )
    Diaptomoidea ( Superfamille )
        Acartiidae ( Famille )
            Acartia ( Genre )
                Euacartia ( Sous-Genre )
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).
Espèce Acartia (Euacartia) southwelli - Planche 1 de figures morphologiquesissued 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).

20 females and 10 males from the Tuticorin (8°56'N, 78°20'E) and 100 females and 50 males from Portonovo (11°52'N, 79°50'E°E)6), plus specimens from Cochin backwaters (10°N, 76°E), Mandovi-Zuari estuaries (15°30'N, 74°E).

Nota female:
- Prosome-urosome ratio 3.7 : 1.
Cephalosome and pediger 1 separate.
-Posterior corners of metasome rounded, naked.
- All urosomal somites usually naked. Fine spinules shown on urosomal somites (fig.1B), and male (fig.1F) present only in specimens from Portonovo; the number of spinules varies within this population; specimens examined from other localities without spinules on urosomal somites.; however, spinules may be present on the urosome somites of animals from other localities (Tranter & Abraham, 1971, have shown the female from Cochin possessing some spinules.
- Caudal rami symmetrical, 1.4 times longer than broad, bearing 5 plumose setae and 1 setule.
Urosomal segments and caudal rami with proportions 46 : 19 : 12: 23 = 100.

Nota male:
- Prosome-Urosome ratio 3.1 : 1.
- Posterior corners of pediger 5 naked.
- Urosomal segments also unusually unarmed (variability shown in fig.1F)
- Caudal rami nearly as broad as long.
- Proportions of urosomal segments and caudal rami 11 : 29 : 23 : 8 : 12 : 17 = 100.

Espèce Acartia (Euacartia) southwelli - Planche 2 de figures morphologiquesissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.71, Fig.3].
Female: A, A2; B, Md; C, Mx1; E, Mxp.

- A2: coxa with 1 single seta,; basis fused with an endopod segment (allobasis) bearing 8 setae at inner margin, 1 seta terminally and 2 distal spinule rows, 2nd and 3rd segments incompletely fused appearing as a bilobed segment each bearing 7 setae; exopod 4-segmented segments incompletely fused (setal formula: 1, 1, 3, 3).
- Md: gnathobase with 5 sharp and 4 blunt teeth; basis with 1 medial seta; endopod with 2 incompletely fused segments, 1st with 2 setae, 2nd with 9 setae; exopod partly fused with basis, 3-segmented (setal formula 1, 1, 4).
- Mx1: praecoxal arthrite with 8 spines like and 1 weak setae; coxal endite with 2 setae, coxal epipodite with 9 developed setae; each of 2 basal endites with 1 thick seta, basal exite with 1 seta; endopod and exopod incompletely fused with 5 and 2 setae each.
- Mx2: praecoxa and coxa with 2 endites each (setal formula 4, 2, 2, 3); basis with 1 large and 1 small seta; endopod 3-segmented (setal formula 1, 2, 4).
- Mxp: praecoxa and coxa fused bearing 5 setae; basis bearing 1 spine like seta; endopod 4-segmented, 1st 3 segments incompletely fused, with 1 seta each; terminal segment with 2 setae;
- Mouthparts of male as in female.

Espèce Acartia (Euacartia) southwelli - Planche 3 de figures morphologiquesissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.72, Fig.4].
Female: A-D, swimming legs 1-4 (respectively).

Espèce Acartia (Euacartia) southwelli - Planche 4 de figures morphologiquesissued 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.

- A1 female 20-segmented, reaching midlength or pediger 5. Segment 4 with 1 spine, segment 8 longest, segments 6, 7, 11, 12, 14, 15 with spinules, terminal segment with 4 setae and 1 aesthetasc.
- Right A1 male 18-segmented, suture between segments 15 and 16 incomplete (arrow head, fig.2B), 2spines present on anterior margin of segment 4, 1 spine each on segments 7 and 12, segments 5 and 6 unarmed, geniculation between segments 13 and 14, segment 14 (fig.2C) armed with 2 larger and 2 smaller spines, 1 seta and 1 aesthetasc.

Espèce Acartia (Euacartia) southwelli - Planche 5 de figures morphologiquesissued from : M. Madhupratap & P. Haridas in Hydrobiologia, 1994, 292/293. [p.73, Fig.5].
Female: A, P5.
Male: B, P5.

- P5 female: symmetrical; 3-segmented, both coxal segments fused; basis oblong with 1 small seta on outer margin at about distal 2/3; base of terminal segment slightly swollen, tapering distally, with a distinct suture at midlength, portion distal to suture serrate.
-P5 male: Right and left coxal segments fused. Right leg basis with seta at distolateral corner; 1st exopodal segment with 1 long slender seta, 2nd exopodal segment with an oblong inner lobe bearing 1 spine, 3rd segment curved with 1 thick spine at midlength on medial margin and another at tip. Left leg basis more than twice as long as broad with outer seta at midlength; 1st exopoal segment short and unarmed, terminal segment medial margin with proximal tuft of hair, 1 spine embedded in a membraneous sheath, the sheath produced and of irregular shape and flanked on distal side by a recurved spine; tip of segment bifurcate, outer process much longer than inner process.

Espèce Acartia (Euacartia) southwelli - Planche 6 de figures morphologiquesIssued 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.

Espèce Acartia (Euacartia) southwelli - Planche 7 de figures morphologiquesissued from : R.B.S. Sewell in Fauna of the Chilka Lake, 1924, 12. [Pl. XLV, Fig.6].
Female and Male (from Chilka Lake).

Espèce Acartia (Euacartia) southwelli - Planche 8 de figures morphologiquesissued 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.

Espèce Acartia (Euacartia) southwelli - Planche 9 de figures morphologiquesIssued 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

Ref. compl.:
Subbaraju & Krishnamurphy, 1972 (p.25, 26 ); 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); Varadharajan & Soundarapandian, 2013 (p.2: occurrence vs stations)
NZ: 2

Carte de distribution de Acartia (Euacartia) southwelli par zones géographiques
Espèce Acartia (Euacartia) southwelli - Carte de distribution 2issued from : C.T. Achuthankutty, N. Ramaiah & G. Padmavati in Pelagic biogeography 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, Porto Novo, G. of Mannar, Sri Lanka Pearl Banks, Pointcalimere-Mallipattinam, Godavari estuary & coastal, Kakinada Bay, Chilka Lake), Bay of Bengal, China Seas (Bohai Sea)
N: 19
(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.: estuaire-néritique.
Les tailles semblent corrélées avec la salinité. 15 à 35 p.1000 in Cochin and the Mandovi-Zuari estuaires
W. Zhang confirme la présence de cette espèce dans les mers de Chine (comm. pers., 2006).
Voir aussi les remarques en anglais
Dernière mise à jour : 06/06/2020

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Razouls C., Desreumaux N., Kouwenberg J. et de Bovée F., 2005-2023. - Biodiversité des Copépodes planctoniques marins (morphologie, répartition géographique et données biologiques). Sorbonne Université, CNRS. Disponible sur [Accédé le 02 juin 2023]

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