Species Card of Copepod
Cyclopoida ( Order )
    Oithonidae ( Family )
        Oithona ( Genus )
Oithona dissimilis  Lindberg, 1940   (F,M)
Syn.: Oithona dissimilis oceanica Lindberg, 1947;
O. hebes : Wellershaus, 1969 (p.276, figs.F,M)
Lindberg, 1940 (p.519, Descr.F,M, figs.F); Sewell, 1948 (p.430); Lindberg, 1955 a (p.467: Rem.); Gonzalez & Bowman, 1965 (p.270, Rem.); Ferrari, 1977 (p.400, Redescr., figs.F, M, Rem.); Nishida, 1985 (p.138, 141); 1985 a (p.142, 143); Chihara & Murano, 1997 (p.937, Pl.198,202: F,M); McKinnon, 2000 (p.108, Rem.); Cornils & Heckmann, 2015 (p.243, Fig. 2, molecular biology)
Species Oithona dissimilis - Plate 1 of morphological figuresissued from : F.D. Ferrari in Proc. Biol. Soc. Washington, 1977, 90 (2). [p.401, Fig.1]. From Tutuila Island, American Samoa.
Female: A, habitus (lateral left side); B, idem (dorsal); C, urosome (ventrolateral left side).
Nota: Metasome segments 1-4 each with a pair of dorsal sensory hairs, (segmet 2 with 2 pairs). Excluding terminal spine, exopod of P1-P4 with 1-1-3, 1-1-3, 1-1-3, 1-1-2 external spines, respectively; 1-1-4, 1-1-5, 1-1-5, 1-1-5 internal setae, respectively. Endopod P1-P4 with 0-0-1, 0-0-1, 0-0-1, 0-0-1 external setae, respectively and 1-1-5, 1-2-5, 1-2-5, 1-2-4 internal setae, respectively.

Male: D, habitus (dorsal); E, idem (ventrolateral right side); F, detail of cephalosome (ventrolateral); G, urosome (ventrolateral left side).
Nota: Prosome laterally with a very complex group of integumental organs in an area comprising posteroventral part of cephalosome and posterior extension or flap of cephalosome overlapping following segment.

Species Oithona dissimilis - Plate 2 of morphological figuresissued from : F.D. Ferrari in Proc. Biol. Soc. Washington, 1977, 90 (2). [p.403, Fig.2]. From Tutuila Island, American Samoa.
Female: A, caudal ramus (ventral); B, Md.

Male: C, Md; D, caudal ramus (ventral); E, A1.

Species Oithona dissimilis - Plate 3 of morphological figuresissued from : F.D. Ferrari in Proc. Biol. Soc. Washington, 1977, 90 (2). [p.405, Fig.3]. From Tutuila Island, American Samoa.
Female: A, Mx2; B, P4 (anterior).
Nota: Three large spines of Mx2 with notch on 2/3 dorsal margin.

Species Oithona dissimilis - Plate 4 of morphological figuresIssued from : S. Wellershaus in Veröff. Inst. Meeresforsch. Bremerh., 1969, 11 (2). [p.277, Fig.88-102]. As Oithona hebes.
Female (from Cochin Backwater, S. India): 88, habitus with ovisacs (dorsal); 90, urosome (ventral); 93, A1 (one terminal seta deformed); 96, A2; 97, Md; 99, P1; 100, P2; 101, exopod of P3; 102, P4 (in endopod onlly the specialized setae fully drawn).
Nota: Eye blue. 5th thoracic segment without hairs on theposterior margin. Caudal rami longer than the 5th thoracic segment; length: breadth = 2.50-2.88. Proportions of the urosomal segments 12, 33, 14, 14, 13; caudal rami 14 %/

Male: 89, habitus (dorsal); 91, urosome (dorsal); 92, urosome (juvenil; dorsal); 94, A1 (sheath not dotted; n = notch; aesthetasc on the end); 95, A2; 98, Md.
Nota: A1 twice geniculated; the proximal geniculation is surrounded by a sheathdistal geniculation with a notch in the segment. Proportions of the urosomal segments: 19, 19, 16, 13, 10, 11; caudal rami 13 %.
Scale : single line = 0.1 mm ; double line = 0.05 mm.

Species Oithona dissimilis - Plate 5 of morphological figuresissued from : K. Lindberg in Rec. Indian Mus., 1940, 42 (2). [p.520, Fig.2].
Female (from Oupalom pond, Pondichery): a, anal segment and caudal rami (dorsal); b, 5th thoracic segment and genital segment (ventral); c, A1; d, A2; e, endopod of P4; f, forehead (ventral).
Nota: Ratio lenths cephalothorax: urosome1.17-1.66:1. Forehead without rostrum, as a bilobated mass ventrally. Genital segment slightly longer than the posterior two segments combined; 2nd to 4th abdominal segments following from length slightly equal. Caudal rami strongly diverging, inner margin without hairs. A1 16-segmented, but sutures between 8th and 9th segments, and 13th and 14th more or less distinct, reaching the middle or posterior margin of the 4th thoracic segment. Exopod 3 of P4 about 2 times the length of the endopod 3. Ovisacs large, comprising each 10 to 22 eggs.

Species Oithona dissimilis - Plate 6 of morphological figuresissued from : K. Lindberg in Rec. Indian Mus., 1940, 42 (2). [p.522].
Dimensions from two females I and II.
Longueur = length; Largeur = wide; queue = urosome ; externe = outer; interne = inner; mediane = medial. Soie = seta; Furca = Caudal rami; Cinquième patte = P5.

Compl. Ref.:
Lo & al., 2004 (p.468, tab.2); Ohtsuka & al., 2008 (p.115, Table 5); Maiphae & Sa-ardrit, 2011 (p.641, Table 2, 3, Rem.); Saitoh & al., 2011 (p.85, Table 4, 5); Chew & Chong, 2011 (p.127, Table 2, 3, abundance vs location); Ueda & al., 2011 (p.2069, size vs salinity, speciation)
NZ: 4

Distribution map of Oithona dissimilis by geographical zones
Species Oithona dissimilis - Distribution map 2Issued from : S. Nishida in Bull. Ocean Res. Inst., Univ. Tokyo, 1985, No 20. [p.143, Fig.94].
Indo-Pacific gepgraphical distribution of Oithona dissimilis.
India (Pondichery, Cochin), Straits of Malacca (upper and lower Sangga estuary), G. of Thailand, China Seas (East China Sea), Taiwan (Tapong Bay), Japan, Samoa Is., Palau Is.
N: 9
(172) F: 0,61-0,67; M: 0,58; (279) F: 0,650-0,579; M: 0,57; (635) F: 0,7-0,61; M: 0,72-0,64; {F: 0,58-0,70; M: 0,57-0,72}
Rem.: brackish (Salinity 4 and 32 p.1000), estuaries, coastal.
Ferrari (1977,p.404) points to Lindberg's (1940) description overlooked an external spine on exopod 3 of P1, corrected it (1947) concerning the variety O. dissimilis oceanica in the pelagic waters of the open sea.
See in Oithona robertsoni Table 1 from McKinnon (2000, p.108).
Last update : 01/06/2017
    to add your remark

 Any use of this site for a publication will be mentioned with the following reference :

Razouls C., de Bovée F., Kouwenberg J. et Desreumaux N., 2005-2017. - Diversity and Geographic Distribution of Marine Planktonic Copepods. Available at http://copepodes.obs-banyuls.fr/en 
[Accessed October 19, 2017]

© copyright 2005-2017 CNRS, UPMC

CNRS   Observatoire Océanologique de Banyuls sur Mer - Laboratoire Arago
UPMC - Paris Universitas


Version française
English version



On the WEB of CNRS


Marine Planktonic Copepods

Marine Planktonic Copepods


Imprimer Contact Accueil Plan du site Accès restreint Retour Une du Labo Imprimer Contact Plan du site Crédits Téléchargez les Plug-Ins