Species Card of Copepod
Calanoida ( Order )
    Metridinidae ( Family )
        Metridia ( Genus )
Metridia asymmetrica  Brodsky, 1950   (F,M)
Brodsky, 1950 (1967) (p.300, figs.F,M); Minoda, 1971 (p.35); Vaupel-Klein, 1970 (p.4, 34, Rem.); Chihara & Murano, 1997 (p.837, tab.6); Markhaseva, 2001 (p.47, figs.F,M)
Species Metridia asymmetrica - Plate 1 of morphological figuresissued from : E.L. Markhaseva in Zoosyst. Rossica, 2001, 9 (1). [p.63, Figs.111-120].
Female (from off cape Shipunsky, Kamchatka): 111, habitus (dorsal view); 112, cephalosome (right lateral view); 113, posterior somite of prosome and urosome (dorsal view); 114, idem (left lateral view); 115, genital somite (ventral view); 116, idem (right lateral view); 117, first leg (coxopod and basipod); 118, first leg (exopod); 119, first leg (endopod); 120, first legs.

Nota : Prosome nearly wice as long as urosome. Rostrum of 2 well developed filaments. Genital somite 1.7-1.8 times as long as wide, asymmetrical, with round spermathecae situated asymmetrically, left one directly above right one. Caudal rami about 2 times as long as wide. A1 24-segmented, reaching anal somite or nearly the middle length of caudal rami. Oral parts and Mxp as described for M. pseudoasymmetrica. P1 very similar to that of M. pseudoasymmetrica.

Species Metridia asymmetrica - Plate 2 of morphological figuresissued from : E.L. Markhaseva in Zoosyst. Rossica, 2001, 9 (1). [p.64, Figs.121-131].

Female: 121, right A1 (segments 1-6); 122, idem (segments 7-9); 123, left A1 (segments 1-4); 124, idem (segments5-9); 125, second leg; 126, second leg (endopod.1); 127, third leg (exopod).

Male: 128, cephalosome (dorsal view); 129, idem (left lateral view); 130, posterior somite of prosome and urosome (dorsal view); 131, idem (left lateral view).

Species Metridia asymmetrica - Plate 3 of morphological figuresissued from : E.L. Markhaseva in Zoosyst. Rossica, 2001, 9 (1). [p.65, Figs. 132-147].
Male: 132, left A1 (segments 1-9); 133, idem (segments 10-15); 134, idem (segments 16-20); 135, idem (segments 17-19, other view); 136, fifth legs; 137, right fifth leg; 138, idem (coxopod, basipod and exopod.1); 139, idem (exopod.2-3); 140, idem (exopod.3); 141, idem (distal part of exopod.3); 142-143, left fifth leg (different positions); 144, left fifth leg (basipod and exopod.1); 145, idem (exopod.1); 146-147, idem (exopod.2-3, different positions).

Nota : Prosome 1.8-2.0 times as long as urosome. Urosomal somite 2 with small anterior swelling covered with spinules on the left and on the right ; urosomal somite 3 with short spinules in left lateral anterior part. Caudal rami about 1.9 times as long as wide. Left A1 20-segmented, geniculated, reaching uromite 4 ; right A1 reaching caudal rami. Shape of P5 segments strongly varies depending of the view.

Species Metridia asymmetrica - Plate 4 of morphological figuresIssued from : K.A. Brodskii in Calanoida of the Far Eastern Seas and Polar Basin of the USSR. Opred. Fauna SSSR, 1950, 35 (Israel Program for Scientific Translations, Jerusalem, 1967) [p.299, Fig.205].
Female (from NW Pacific): habitus (dorsal and lateral left side); S2En1, hooks on endopodal segment 1 of P2; S5, P5.

Male: habitus (dorsal); Ve, urosome (ventral); S5 (Le: left leg; Ri: right leg).

Compl. Ref.:
Minoda, 1958 (p.253, Table 2, abundance); Yamaguchi & al., 2002 (p.1007, tab.1); Yamaguchi & al., 2004 (p.480, tab.2); Ikeda & al., 2006 (p.1791,Table 2); Galbraith, 2009 (pers. comm.); Homma & Yamaguchi, 2010 (p.965, Table 2); Homma & al., 2011 (p.29, Table 2, 3, 4, abundance, feeding pattern: suspension feeders); Takenaka & al., 2013 (p.201, DNA sequences vs luciferase)
NZ: 3

Distribution map of Metridia asymmetrica by geographical zones
off SE Hokkaido, off SE Kuril Is., Station Knot, Okhotsk Sea, Bering Sea, S Aleutian Basin, S Aleutian Is., Station "P", off British Columbia
N: 14
(22) F: 4,2-3,9; M: 3,9-3,6; (205) M: 3,45; (208) F: 4,2; M: 3,86-3,6; (823) F: 4,2-3,9; M: 3,5-3; {F: 3,90-4,20; M: 3,0-3,90}

The mean female size is 4.080 mm (n = 5; SD = 0.1643), and the mean male size is 3.559 mm (n = 7; SD = 0.2995). The size ratio (male : female) is about 0.87.
Rem.: meso-abyssal.
Last update : 11/02/2016
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Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2024. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed May 18, 2024]

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