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Marine Planktonic Copepods
Oithona pacifica  Nishida, 1985   (F,M)
Taxonomy
Order Cyclopoida
Family Oithonidae

Synonymy

Paroithona pacifica Nishida, 1985 a (p.109, Descr.F, figs.F, p.112-113 Rem: historical account); Ferrari & Böttger, 1986 (p.277, figs.F,M, Rem.: polymorphism)

References

Boxshall & Halsey, 2004 (p.611: Rem.)

Figures

Plate 1 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.276, Fig.1]. As Paroithona pacifica.
Female (from N Red Sea): A, habitus (lateral right side); B, urosome (lateral left side); C, urosomal segments 1-2 (dorsal); D, forehead (dorsal); J, genital segment with spermatophore (lateral right side).
Nota: Rostrum absent. Forehead (dorsally) with internally with paired clusters of polygonal cells. A1 (apparently 9-segmented). Caudal ramus length 1.7 width, armed with 1 lateral seta, ventral surface hairs, 1 dorsal and 4 terminal setae

Male: E, habitus (lateral left side); F, urosome (lateral right side); G, urosomal segments 1-3 (dorsal); H, forehead (dorsal).
Nota: Rostrum absent. Forehead (dorsally) with internally small clusters of polygonal cells internal to upper lip.
Plate 2 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.278, Fig.2]. As Paroithona pacifica.
Female: A, A1; B, caudal ramus.

Male: C, A1; D, caudal ramus.
Plate 3 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.280, Fig.3]. As Paroithona pacifica.
Female: A, P1; B, P2.

Male: C, P1; D, P2.
Plate 4 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.281, Fig.4]. As Paroithona pacifica.
Female: A, P3; B, P4.
Nota: P3 and P4 exhibit variability in the number of external spines on exopods (dettection of such variability is complicated by the small size of these spines). 22 specimens specimens with symmetrical exopods on legs 3 and 4 had 3 armament types: (14 specimens) P3: 1-0-2; P4: 1-0-2; (7 specimens) P3: 1-0-2; P4: 1-0-1; (1 specimen) P3: 1-1-2; P4: 1-1-1. 6 specimens had asymmetrical armament on 1 pair of legs 3 and 4 (left/right) : (1 specimen) P3: 1-1-2/1-0-2; P4: 1-0-2; (1 specimen) P3: 1-1-2/1-0-2; P4 broken off; (1 specimen) P3: 1-0-2/1-0-1; P4: 1-0-2; (2 specimens) P3: 1-0-2; P4: 1-01/1-0-2; (1 specimen P3: 1-0-2; P4: 1-0-2/1-0-1.

Male: C, P3; D, P4.
Plate 5 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.282, Fig.5]. As Paroithona pacifica.
Female: A, Md; B, Mx1.

Male: C, Md; D, Mx1.
Plate 6 issued from : F.D. Ferrari & R. Böttger in Proc. Biol. Soc. Washington, 1986, 99 (2). [p.283, Fig.6]. As Paroithona pacifica.
Female: A, A2; B, Mx2; C, Mxp.

Male: D, A2; E, Mx2; F, Mxp.
Plate 7 Issued from : S. Nishida in Bull. Ocean Res. Inst., Univ. Tokyo, 1985, No 20. [p.110, Fig.64]. As Paroithona pacifica.
Female: a, habitus (dorsal); b, forehead (lateral); c, P5; d, A2; e, Md; f, Md (biting edge); g, Mx1.
Proportional lengths of urosome segments and caudal ramus 12:35:15:18:11:9. Thoracic segment 5 produced laterally toward posterior end. Anal segment short, length 0.8-0.9 times width, posterior margin not concave but slightly produced posteriorly, with setules ventrally. Caudal ramus very short, length 1.1-1.5 times width, 0.7-0.8 times anal segment. Basipodal segments 1 and 2 of A2 fused, with 2 marginal setae, medial and distal.
Plate 8 Issued from : S. Nishida in Bull. Ocean Res. Inst., Univ. Tokyo, 1985, No 20. [p.111, Fig.65]. As Paroithona pacifica.
Female: a, Anal segment and caudal rami (dorsal); b, idem (ventral); c, A1; d, Mx2; e, Mxp; f, P1; g, P2; h, P3; i, P4.
Nota: A1 short, without posteroventral row of minute teeth, length 0.8-0.9 times prosome

Distribution

NZ: 3

Distribution map of Oithona pacifica by geographical zones


Localisations

Red Sea, G. of Aden, W Indian, SE Pacif.

Quotations

N: 2

Dimensions (mm)

(627) F: 0,46-0,41; (657) F: 0,47-0,43; M: 0,4-0,37; {F: 0,41-0,47; M: 0,37-0,40}

Remarks

epi-mesoplanktonic.
Nishida (1985, p.112) points to this species is distinguished from pulla Farran (1913) and flemingeri Ferrari & Bowman (1980) in having 2 inner marginal setae on A2 and 1, 0, 2 outer marginal spines on exopod of P3 and P4.
Last update : 24/01/2015

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