Gaussia sewelli - Species Card - Marine Planktonic Copepods

Gaussia sewelli Saraswathy, 1973 (F,M)

Taxonomy

Order Calanoida

details

Family Metridinidae

details

Genus Gaussia

details list species for this Genus

Abbreviations or symbols

Synonymy

Metridia scotti : Sewell, 1913 (p.354);
Gaussia princeps : Sewell, 1932 (p.270, fig.F,M, Juv.); 1947 (p.173); Brodsky, 1950 (1967) (part., p.312, figs. Ind. Oc: F,M, non figs. NP: F,M, Rem.); ? Tanaka & Omori, 1967 (p.251); Grice & Hulseman, 1967; Saraswathy, 1971

References

List of the studied authors

Saraswathy, 1973 a (p.192, figs.F,M); Björnberg & Campaner, 1988 (p.351, Rem.); Padmavati & al., 1998 (p.347); Soh & al., 1998 (p.172, figs.F,M, fig.7: carte, Rem.); Suarez-Morales, 2007 (40, tabl.2, 3); Stephen ( Data sheets of NIO, Kochi, India (on line, Diagnostic characteristics, figs.F,M).

Figures

Plate 1 Issued from : R.B.S. Sewell in Mem. Indian Mus., 1932, X (continued). [P;.V]. As Gaussia princeps.
Female (from N Indian Ocean): 1, habitus (dorsal); 2, A1; 3, A2; 4, P1; 5, P2; 6, P3; 7, P4.

Species Gaussia sewelli - Plate 2 of morphological figures

Plate 2 Issued from : R.B.S. Sewell in Mem. Indian Mus., 1932, X (continued). [P;.VI]. As Gaussia princeps.
Male: 1, habitus (dorsal); 2, right A1; 4, P5.

Female: 3, Mxp; 4, P5; 5,

Species Gaussia sewelli - Plate 3 of morphological figures

Plate 3 Issued from : R.B.S. Sewell in Mem. Indian Mus., 1932, X (continued). [p.271, Fig.92]. As Gaussia princeps.
Female (from Laccadive Sea): habitus, dorsal (arrangement of the cutaneous pores).

Plate 4 Issued from : R.B.S. Sewell in Mem. Indian Mus., 1932, X (continued). [p.276, Fig.93, a]. As Gaussia princeps.
Female: a, urosome (lateral left side).

Species Gaussia sewelli - Plate 5 of morphological figures

Plate 5 issued from : H.Y. Soh, S. Ohtsuka, H. Imabayashi & S. Sawamoto inSpecies Diversity, 1998, 3. [p.178, Fig.5 G].
Female (from the Indian Ocean): G, distal seta on 3rd exopodal segment of rigt P5.

Species Gaussia sewelli - Plate 6 of morphological figures

Plate 6 issued from : H.Y. Soh, S. Ohtsuka, H. Imabayashi & S. Sawamoto inSpecies Diversity, 1998, 3. [p.180, Fig.6 H].
Male (from the Indian Ocean): H, P5 (posterior; distal two exopodal segments of right leg torted).

Species Gaussia sewelli - Plate 7 of morphological figures

Plate 7 issued from : R. Stephen, 2007 [Data sheets of NIO, Kochi, India (on line)]. After M. Saraswathy, 1973.
Female (from Arabian Sea and Bay of Bengal): a, last thoracic segment and urosome (dorsal).

Male: c, last thoracic segment and urosome (lateral).
Nota: Posterolateral corners of last thoracic segment: Backwardly directed hardly divergent spines.
Genital segment: Symmetrical lateral inflations.
Caudal rami distal protuberance: Barely evident.

Plate 8 issued from : M. Saraswathy in Handbook to the Intern. zoopl. Coll., Cochin-18, Kerala State, India, 1973. [p.193, Figs.4, 5].
Female (from Indian Ocean): 4, P5.

Male: 5, P5.

Species Gaussia sewelli - Plate 9 of morphological figures

Plate 9 issued from : M. Saraswathy & J.M. Bradford in N. Z. Jl mar. freshw. Res., 1980, 14 (1). [p.80, Fig.1].
Male: right A1.
Positions of various integumental structures indicated. A, ventral view; B, dorsal view of proximal part; A, aesthetasc; P, pore; Pr, pits with radiating ridges; Se, seta; Sq, suat appendage.

Species Gaussia sewelli - Plate 10 of morphological figures

Plate 10 issued from : M. Saraswathy & J.M. Bradford in N. Z. Jl mar. freshw. Res., 1980, 14 (1). [p.81, Fig.2].
SEM details of male right A1: A, segment 16 showing aesthetasc (A) and associated pit with radiating pores (x825); B, pit with radiating ridges (x4650); C, segment 11 showing the squat appendage (x860).
Nota: Pits with radiating ridges: These are on the ventral surface, always at the base of an aesthetasc, in the female and the male. The floor of the pit appears to be raised towards the centre and is almost covered in a radial pattern apparently by extensions of the surronding integuments.
Squat appendage on male segment 11: This is on the anterodistal corner of segment 11 of the right A1 and ends in separate hemisperical and cone-shaped protuberances without pores or other external structures. It is apparently articulated with its segment and appears to be a modified seta judging from its position relative to the aesthetasc. This structure was found on all adult males of G. sewelli and G. scotti (= G. princeps).

Complementary References

List of the studied authors

Madhupratap & Haridas, 1986 (p.105, tab.1); Kazmi, 2004 (p.228, as swelli, Rem.: p.232)

Distribution

NZ: 1 + 1 doubtful

Distribution map of Gaussia sewelli by geographical zones

Distribution map of Gaussia sewelli for the Zone Indian Ocean

Additional Maps & Charts

Species Gaussia sewelli - Distribution map 3

Map 3 issued from : H.Y. Soh, S. Ohtsuka, H. Imabayashi & S. Sawamoto inSpecies Diversity, 1998, 3. [p.182, Fig.7].
Zoogeographical distribution of Gaussia princeps, G. sewelli and G.asymmetrica

Species Gaussia sewelli - Distribution map 4

Map 4 issued from : M. Saraswathy in Handbook to the Intern. zoopl. Coll., Cochin-18, Kerala State, India, 1973. [p.193].
Localities from G. scotti (= G. princeps) (black circle) and G. sewelli (white circle) obtained.

Localisations

Geographical glossary

N Indian (Arabian Sea, Bay of Bengal), ? Japan

Quotations

N: 3

Dimensions (mm)

References of the authors concerning dimensions

(44) F: 9,5-9; M: 9,5-8; (94) F: 9,9-9,4; M: 9,6-8,4; {F: 9,00-9,90; M: 8,00-9,60}

The mean female size is 9.450 mm (n = 4; SD = 0.3697), and the mean male size is 8.875 mm (n = 4; SD = 0.7974). The size ratio (male : female) is 0.94..

Remarks

meso-bathypelagic.
A doubt subsists on the identification made by Tanaka & Omori (1967) if one admits G. sewelli.
See remarks in Gaussia princeps.
For Saraswathy (1973 a, p.193) the first record of the genus Gaussia from the Indian Ocean was that of Sewell (1913). There is an erroneous statement in Wolfenden (1911) that Gaussia was obtained in Gardiner's collection from the Indian Ocean. The drawings of Sewell (1932) are clear enough to recognize them as different of G. scotti (= Gaussia princeps) by several authors.

Last update : 13/02/2016

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