Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Euchaetidae ( Family )
            Euchaeta ( Genus )
Euchaeta marinella  Bradford, 1974   (F,M)
Syn.: Euchaeta concinna : C.B. Wilson, 1950 (p.212, figs.F)
Ref.:
Bradford, 1974 (p.168, figs.F,M, fig.7, Rem.); Bradford & al., 1983 (p.20, figs.F,M, Rem.); Park, 1995 (p.17, Rem.F, figs.F)
Species Euchaeta marinella - Plate 1 of morphological figuresissued from : J.M. Bradford in Pacific Science, 1974, 28 (2). [Fig.4, p.165; Fig.6, p.166].
Female: genital segment: i, dorsal view; j, left side; k, right side; l, ventral view.
Nota: Genital segment in dorsal view with out projection on left; right side with long flat projection which does not obscure more ventral, triangular projection (fig.4, i).

Male: e, P5 (sp.: spermatophore); f, serrate lamella of left P5 exopod segment 2.
Nota: Thin-skinned lobe on distal part of left exopod segment 3 of P5 arises very close to group of spines on that segment and barely extends beyond base of terminal spiniform process. Serrate lamella of exopod of segment 2 with distalmost part bordered by small teeth flanked distolaterally by larger teeth. Thick spine arising at base of serrate lamella ore than 1/2 length of lamella.


Species Euchaeta marinella - Plate 2 of morphological figuresissued from : T. Park in Bull. Scripps Inst. Oceanogr. Univ. California, San Diego, 1995, 29. [p.115, Fig.5].
Female: a, forehead (left side); b, urosome (left side); c, genital somite (left side); d, idem (tilted clockwise); e, genital somite (right side); f, idem (tilted clockwise); g, genital somite (dorsal); h, idem (ventral view); i, idem (tilted counterclockwise); j, first leg (anterior); k, second leg (anterior).
pgf = posterior lobe of genital flange.

Nota: Laterally, rostrum relatively large, pointing at an angle of about 20° with respect to anterior dorsal wall of forehead.
In both dorsal and ventral vioew, left side of genital somite smoothly curved (as in E. rimana).Ventrally, right side of genital somite with a tubercular outgrowth at middle, which in lateral view appears as a rounded ridge posterior to genital flange. Left genital flange smaller than right and deeply divided into 2 lobes (as in E. marina); the posterior lobe is almost hidden behind the anterior lobe when viewed laterally but is clearly visible when the somite is tilted clockwise. Right genital flange in lateral view single-lobed and nearly rounded. Ventrally, two opposing genital flanges extending mediad to meet each other without leaving a gap in between (as in E. rimana.
Cephalosomal appendages as in E. marina except that all terminal setae of the 4 proximal lobes of Mx2 are furnished with long spinules in addition to rows of fine spinules (as in E. indica).
Swimming legs similar to those of E. marina but 2nd outer spine of 3rd exopodal segment of P2 barely reaching midway to base of 3rd outer spine and marginal lobe bearing 2nd outer spine is separated from segment by a relatively shallow incision.


Species Euchaeta marinella - Plate 3 of morphological figuresissued from : J.M. Bradford, L. Haakonssen & J.B. Jillett in Mem. N.Z. Oceanogr. Inst., 1983, 90. [p.21, Fig.6].
Female: A, habitus (lateral right side); B-E, genital segment (dorsal, left lateral, right lateral, ventral, respectively); F, exopod of P1; G, exopod segment 3 of P2.
- P1 exopod: Bb ≥ 1/2 BC; Cc ≥ BC.
- P2 exopod: Aa ± 3/4 AB; Bb ≤ 1/2 BC; Cc ≤ 1/2 CD. (see code of lengths outer spine in the Genus' figure of Paraeuchaeta, or in Paraeuchaeta sp. A).

Male: H, habitus (lateral left side); I, P5; J, terminal part of left P5 exopod.


Species Euchaeta marinella - Plate 4 of morphological figuresissued from : J.M. Bradford in Pacific Science, 1974, 28 (2). [p.166, Fig.5, c].
Female: c, genital field and right border of genital segment.

Nota:
Genital field in ventral view with genital pads not meeting in midline, gap between them about 1/2 width of right pad.


Species Euchaeta marinella - Plate 5 of morphological figuresEuchaeta marinella Female:
1 - See Key to marina species Group.
2 - Laterally, genital somite less than 1.5 times as long as deep (Fig.5-b).
3 - In P2 exopod, 2nd outer spine of 3rd segment shorter than outer spine of 2nd segment (Fig.5-k).


Species Euchaeta marinella - Plate 6 of morphological figuresissued from : J.M. Bradford in Pacific Science, 1974, 28 (2). [p.164, Fig.3].
Comparison between exopods of P1 and P2 female of Euchaeta marina (a, b), Euchaeta rimana (c, d) and Euchaeta marinella (e, f).

Nota: Exopod of P1: Bb ± 2/3 BC, Cc ± 4/3 BC. Exopod of P2: Aa ≤ AB, Bb ± 1/2 BC, Cc ≤ CD.
In E. rimana P1 exopod: Bb ±2/3 BC, Cc ≥ BC.
In E. marinella exopod of P1: Bb ≥ 1/2 BC, Cc ≥BC; exopod of P2: Aa ± 3/4 AB, Bb ≤ 1/2 BC, Cc ≤ 1/2 CD.


Species Euchaeta marinella - Plate 7 of morphological figuresissued from : J.M. Bradford in Pacific Science, 1974, 28 (2). [p.167, Table 2]
Female and Male: comparison between Euchaeta marinella and allied forms.

Compl. Ref.:
Dessier, 1983 (p.89, Tableau 1, Rem. p.97 & al., %); M. Lefèvre, 1986 (p.33, 40); Dessier, 1988 (tabl.1); Heinrich, 1990 (p.17); Suarez-Morales & Gasca, 1998 a (p.109); Hernandez-Trujillo & Esqueda-Escarcega, 2002 (in Appendix); Razai & al., 2004 (p.490, tab.2); Satapoomin & al., 2004 (p.109, tab.6); Rezai & al., 2005 (p.157, Table 5: spatial & temporal variations); W.-B. Chang & al., 2010 (p.735, Table 2, abundance); Maiphae & Sa-ardrit, 2011 (p.641, Table 2, 3, Rem.); Melo Jùnior & al., 2013 (p.363, Table 2, egg production);
NZ: 6

Distribution map of Euchaeta marinella by geographical zones
Species Euchaeta marinella - Distribution map 2issued from: J.M. Bradford in Pacific Science, 1974, 28 (2). [Fig.7, p.167].
Distribution of Euchaeta marina, E. rimana and E. marinella based on specimens seen by the author.
Species Euchaeta marinella - Distribution map 3Issued from : A. Dessier in Oceanol. Acta, 1983, 6 (1). [p.100, Fig.8 A].
Geographic distribution of Euchaeta marinella along the transect Noumea (New Caledonia) to Panama.
black square: more than 18 organisms; black point inside square: 1 to 18 organisms.
Nota: Sampling by net (mesh aperture = 330 µ) between depth 5 and 10 m, 34 hours after sunset. From November 1977 to September 1981 (90 % of samples obtained since 1979).
Species Euchaeta marinella - Distribution map 4Issued from : J.M. Bradford, L. Haakonssen & J.B. Jillett in N. Z. Oceanogr. Inst. Memoir 90, 1983 [p.128, Top left, 129].
Distribution of Euchaeta indica, E. marinella and E. rimana in the south-west Pacific.
Loc:
NE Indian (off Phuket), Straits of Malacca, Pacif. (tropical), Taiwan (south), Philippines, New Caledonia, New Zealand, NE Easter Is., NE Tuamotu Is., Moorea Is. (lagoon), Pacif. (SE (ropical), W Mexico, ? NW Pacif.

Type locality: 23°01.2'S, 166°19'W.
N: 11
Lg.:
(3) F: 3-2,86; (53) F: 2,68-2,35; M: 2,55-2,3; {F: 2,35-3,00; M: 2,30-2,55}

The mean female size is 2.723 mm (n = 4; SD = 0.2808) and the mean male size is 2.425 mm. The size ratio (male : female) is estimated about 0.93 (0.89-0.96), or ± 93 % before other measures.
Rem.: For Park (1995, p.14) this species belongs to ‘’marina’’ Group. And found this species only in the central South Pacific at 25°S, 155°W.
This species corresponds to numerous citations of E. marina in the Pacific.
Satapoomin & al. (2004) report this species in the NE Indian Ocean.
Last update : 19/07/2021
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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 December 03, 2024]

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