Species Card of Copepod
Monstrilloida ( Order )
    Monstrillidae ( Family )
        Cymbasoma ( Genus )
Cymbasoma gigas  (A. Scott, 1909)   (F)
Syn.: Thaumaleus gigas A. Scott,1909 (p.240, figs.F); Davis, 1949 a (p.250); Lacroix & Filteau, 1971 (p.718); Isaac, 1975; Tremblay & Anderson, 1984 (p.8, Rem.); Bernier & al., 2002 (p.651, tab.1)
Suarez-Morales, 2001 a (p.53, Redescr.F, figs.F); 2011 (p.9)
Species Cymbasoma gigas - Plate 1 of morphological figuresIssued from : A. Scott in The Copepoda of the Siboga Expedition Part I. Siboga-Expeditie XXIX a., 1909. [Pl. LVIII, Figs.9-10]. As Thaumaleus gigas.
Female (from off North Ubian, Sulu Islands) ): 9, habitus (dorsal); 10, P5.

Nota: Cephalic segment very long, two and one-third times longer than the posterior end.
The first segment is contracted in front and much inflated behind.
Frontal margin narrow and slightly concave.
Abdomen 2-segmented. Genital segment sub-quadrangular in shape., slightly longer than the anal segment and is traversed by a distinct suture.
Anal segment rather shorter than the genital segment. It is very narrow in front and is much expanded at the posterior end.
Caudal rami nearly as long as the anal segment; each caudal ramus furnished with 1 marginal seta and 2 apical setae.
A1 short, 4-segmented, and equal to about one-sixth of the length of the cephalic segment.
P5 moderately broad; apex bi-lobed; the inner lobe does not extend beyond the apex of the outer lobe, without setae; the outer lobe furnished with 3 moderately long setae

Species Cymbasoma gigas - Plate 2 of morphological figuresIssued from : E. Suarez-Morales in Bull. Inst. R. Sci. Nat. Belgique, Biologie, 2001, 71. [p.55, Figs.1-6].
Female (from lectotype: coll. Siboga Expedition, St. 99, Sulu Islands): 1, habitus (lateral); 2, habitus (dorsal); 3, habitus (lateral); 4, oral papilla (lateral); 5, anterior margin of head (lateral); 6, anterior margin of head (lateral).

Nota: Oral papilla lying midventrally 0.95-0.92 of way back along cephalothorax.
A1 4-segmented; ratio of length of segments from proximal to distal: 17.4 : 20 : 15.5 : 47.1 = 100; A1 relatively short, slightly longer than 16% of cephalothorax length, armed with 0, 1; V; I; 6, II setae (Arabic numerals and spines (Roman numerals). Cephalon and 1st pedigerous somite fused, following by 3 free succeding pedigerous somites each bearing a pair of biramous swimming legs. Urosome consisting of 5th pedigerous somite, genital double-somite, and 1 free abdominal somite. Urosome relatively short, excluding caudal rami accounts for 10% of total body length.

Species Cymbasoma gigas - Plate 3 of morphological figuresIssued from : E. Suarez-Morales in Bull. Inst. R. Sci. Nat. Belgique, Biologie, 2001, 71. [p.56, Figs.7-13].
Female: 7, right A1 (dorsal view; marked using setal nomenclature); 8, left A1 (dorsal view; using setal nomenclature); 9, anal somite and caudal rami (ventral view); 10, urosomites showing P5 and posterior processes arrowed (ventral view); 11, intercoxal plate of P4; 12, intercoxal plate of P1; 13, P5 (ventral view).

Nota: Genital double-somite subquadrate, outer margins slightly globose, posterior margin straight; somite with dorsal suture at midlength, with posterior ventral surface rugose, ending in pair of subtriangular processes (arrowed). Double-genital somite representing slightly more than 1/3 length of urosome. Ratio of length of 5th pedigerous somite, genital double-somite and free abdominal somite: 34.7 : 39 : 26.3 = 100.Medial portion of genital double-somite moderately swollen on ventral anterior margin, probably representing base of ovigerous spines (absent in the lectotype). Anal somite much narrower than genital double-somite, with notched lateral margins. Caudal rami rectangular, 2 times longer than wide, moderately divergent, bearing 3 terminal setae (broken off on lectotype).

Species Cymbasoma gigas - Plate 4 of morphological figuresIssued from : E. Suarez-Morales in Bull. Inst. R. Sci. Nat. Belgique, Biologie, 2001, 71. [p.57, Figs.14-19].
Female: 14, 4th pedigerous and urosomites (lateral); 15, P1 showing peculiar spine on 1st exopod (arrowed); 16, exopod of P3; 17, exopod of P2; 18, P4; 19, P5 (modified from A. Scott's illustration, showing position and length of fifth leg's setae.

Species Cymbasoma gigas - Plate 5 of morphological figuresIssued from : E. Suarez-Morales in Bull. Inst. R. Sci. Nat. Belgique, Biologie, 2001, 71. [p.54].
Female: Armature of swimming legs.
Number of setae: Arabic numerals; number of spines: Roman numerals.

Compl. Ref.:
Grygier, 1994 a (p.28, 45, 65, Rem.); Suarez-Morales & Palomares-Garcia, 1999 (p.197, tab.1)
NZ: 3

Distribution map of Cymbasoma gigas by geographical zones
Sulu Is. (off N Ubian), G. of St. Lawrence, Baie des Chaleurs, Red Sea.

Type locality: Sulu Islands.
N: 4
(5) F: 8; (875) F: 8,2*; {F: 8,00-8,20}
*: measured from anterior end of head to posterior margin of anal somite (caudal rami excluded)
Last update : 02/01/2015
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Razouls C., Desreumaux N., Kouwenberg J. and de Bovée F., 2005-2023. - Biodiversity of Marine Planktonic Copepods (morphology, geographical distribution and biological data). Sorbonne University, CNRS. Available at http://copepodes.obs-banyuls.fr/en [Accessed March 31, 2023]

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