Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Aetideidae ( Family )
            Gaetanus ( Genus )
Gaetanus brevicornis  Esterly, 1906   (F,M)
Syn.: Gaetanus hamatus A. Scott, 1909 (p.50, figs.juv.F); Björnberg, 1973 (p.323, 386);
G. rectus Wolfenden, 1911 (p.232, figs.F); Sewell, 1929 (p.105); 1948 (p.500, 520, 545);
G. ascendens Esterly, 1913 (p.182, figs.F); Sewell, 1948 (p.556, 563); Brodsky, 1950 (1967) (p.166, figs.F); Vives, 1982 (p.291);
G. curvispinus C.B. Wilson, 1950 (p.229, figs. F,M)
Esterly, 1906 a (p.56, Descr.F, figs.F); Sewell, 1947 (p.58, 60, figs.F); Brodsky, 1950 (1967) (p.165, figs.F); Marques, 1953 (p.98, figs.M, Rem.); Vervoort, 1963 b (p.128, Rem.); Tanaka & Omori, 1970 (p.133, figs.F); Park, 1975 a (p.23, figs.F); Bradford & Jillett, 1980 (p.48, figs.F,M, Rem., distribution chart); Markhaseva, 1996 (p.187, figs.F,M); Chihara & Murano, 1997 (p.687, Pl.43: F); Bradford-Grieve & al., 1999 (p.879, 922, figs.F,M)
Species Gaetanus brevicornis - Plate 1 of morphological figuresissued from : E.L. Markhaseva in Proc. Zool. Inst. RAN, St. Petersburg, 1996, 268. [p.188, Fig.146].
Female (specimen from NW Pacif.: Marian Trench). Ce: forehead (lateral and dorsal, respectively); Pmd: mandibular palp; GntbMd: gnathobase of Md (partial).

Species Gaetanus brevicornis - Plate 2 of morphological figuresissued from : E.L. Markhaseva in Proc. Zool. Inst. RAN, St. Petersburg, 1996, 268. [p.189, Fig.147].
Female (specimen from NW Pacif.: Marian Trench). P1-P4: legs 1-4.
Male (from C.B. Wilson, 1950).

Species Gaetanus brevicornis - Plate 3 of morphological figuresissued from : T. Park in Bull. Mar. Sci., 1975, 25 (1). [p.22, Fig.7].
Female: A, B, habitus (lateral, dorsal, respevtively); C, D, posterior part of metasome and urosome (dorsal, lateral); E, forehead (lateral); F, Mx2; G, coxa of Mxp; H, P1 (anterior); I, P2 (anterior); J, coxa of P4 (partial, posterior). P1, P2, P4: legs

Species Gaetanus brevicornis - Plate 4 of morphological figuresissued from : J.M. Bradford & J.B. Jillett in Mem. N.Z. oceanogr. Inst., 86, 1980. [p.49, Fig.31].
Female: A, habitus (dorsal); B, idem (lateral left side); C, basipod 1 of Mxp; D, exopod of P1; E, internal edge of basipod 1 of P4.

Species Gaetanus brevicornis - Plate 5 of morphological figuresissued from : R.B.S. Sewell in The John Murray Expedition, 1933-34, Scientific Reports, VIII (1), 1947. [p.61, Fig.9].
Female (from Arabian Sea): A, P1; B, basal portion of Mxp.

Nota: Proportional lengths of cephalothorax and abdomen as 77 to 23. The proportional lengths of the various segments of the body (cephalon to caudal rami) as 518:74:74:94:90:47:33:33:37 = 1000. Head and 1st pediger segment fused, 4th and 5th fused. The lateral horns on the 5th thoracic segment are rather short and stout, directed somewhat outwards and upwards.2nd and 3rd urosomal segments fringed along their posterior margins with closely apposed, short, hair-like spines. A1 reaches back to about the end of the caudal rami, 8th and 9th segments fused, 24th and 25th separate. In A2 the proportional lengths of the exopod and endopod as 42 to 32; the proximal seta arising from the 2nd segment of the exopod springs fom a raised papilla. Mxp with the great length of the free process of the lamella on the basal segment ( this reaches to well beyond the distal margin of the segment).In P2, a gland opens to he surface at the base of the marginal spine on the 1st and 2nd segments of the exopod and near the base of the 3rd marginal spine on the 3rd segment.

Species Gaetanus brevicornis - Plate 6 of morphological figuresissued from : A. Scott in Siboga-Expedition, 1909, XIX a. [Plate IX, Figs.16-22]. As Gaetanus hamatus.
Female (from Banda Sea): 16, habitus (dorsal); 17, forehead (lateral); 18, last thoracic and genital segments (left side); 19, rostrum; 20, Mxp (basal portion); 21, P1; 22, P4 (basal portion).

Species Gaetanus brevicornis - Plate 7 of morphological figuresissued from : R.N. Wolfenden in Die Marinen Copepoden der Deutschen Südpolar-Expedition 1901-1903, 1911. [p.232, Fig.18]. As Gaetanus rectus.
Female (from SE Ascension Island): a, forehead (lateral); b, Mxp.

Species Gaetanus brevicornis - Plate 8 of morphological figuresissued from : R.N. Wolfenden in Die Marinen Copepoden der Deutschen Südpolar-Expedition 1901-1903, 1911. [Pl.XXVI, Figs.14)16]. As Gaetanus rectus.
Female: 14, last thoracic segment and urosome (dorsal); 15, idem (lateral, right side); 16, P1.

Species Gaetanus brevicornis - Plate 9 of morphological figuresissued from : C.O. Esterly in Univ. Calif. Publs Zool., 1906, 3 (5). [Pl.IX, Fig.4].
Female (from San Diego, California): 4, dorehead (lateral).

Species Gaetanus brevicornis - Plate 10 of morphological figuresissued from : C.O. Esterly in Univ. Calif. Publs Zool., 1906, 3 (5). [Pl.XII, Fig.55].
Female: 55, 1st basal of Mxp.

Species Gaetanus brevicornis - Plate 11 of morphological figuresissued from : C.B. Wilson in Bull. U.S. natn. Mus., 1950, 100, 14 (4). [Pl. 10, Figs.108-110, 112-113]. As Gaetanus curvispinus.
Female (from 20°29'S, 103°26'W): 108-109, habitus (dorsal and lateral, respectively); 110, basipod of P4.

Male: 112, P5; 113, forehead (lateral).

Species Gaetanus brevicornis - Plate 12 of morphological figuresIssued from : C.O. Esterly in Univ. Calif. Publs Zool., 1913, 11 (10). [Pl. 10, Figs. 1, 3, 6]. As Gaetanus ascendens.
Female (from S. California); 1, abdomen and part of last thoracic segment (lateral view); 3, same (dorsal view); 6, forehead (lateral view).

Nota: A1 a little longer than the cephalothorax.1st segment of Mxp has the characteristic lamella. The 1st basal segment of P4 has the row of hair-like spines.
Unpigmented coloration.

Species Gaetanus brevicornis - Plate 13 of morphological figuresGaetanus brevicornis female:
1 - Anterior part of cephalon with frontal spine.
2 - Exopodal segment 1 of A2 without seta, segment 2 with 2 setae. 2nd internal lobe of Mx1 with 4 setae. Exopod of P1 always with 2 external sopines.
3 - Mxp protopodite with lateral plate.
4 - Exopodal segment 2 of A2 with 2 setae.
5 - Spines on last thoracic segment curved dorsally (lateral view).

Compl. Ref.:
Sewell, 1948 (p.330, 529, 531, 540, 541, 552, 556, 562); Grice, 1963 a (p.495); Lee & al., 1971 (p.1151); Deevey & Brooks, 1977 (p.256, tab.2, Station "S"); Heinrich, 1990 (p.17); Shih Young, 1995 (p.67); Suarez-Morales & Gasca, 1998 a (p108); Yamaguchi & al., 2002 (p.1007, tab.1); Galbraith, 2009 (pers. comm.); Homma & Yamaguchi, 2010 (p.965, Table 2); Dias & al., 2010 (p.230, Table 1); Homma & al., 2011 (p.29, Table 2, abundance, feeding pattern: suspension feeders); Teuber & al., 2013 (p.1, Table 3, enzyme activity); in CalCOFI regional list (MDO, Nov. 2013; M. Ohman, comm. pers.); Bode & al., 2018 (p.840, Table 1, respiration & ingestion rates, depth)
NZ: 15

Distribution map of Gaetanus brevicornis by geographical zones
Species Gaetanus brevicornis - Distribution map 2Issued from : J.M. Bradford & J.B. Jillett in New Zealand Ocean. Inst. Memoir, 86, 1980. [p.89, Figs.64].
Distribution of several species of Gaetanus in the Tasman Sea and around New Zealand.
Species Gaetanus brevicornis - Distribution map 3Issued from : M. Bode, R. Koppelmann, L. Teuber, W. Hagen & H. Auel inGlobal Biogeochemical Cycles, 2018, 32. [p.844, Table 1).
Cf. explanations of these measures in Calanoides natalis from the same authors.
Compare with Gaetanus pileatus, G. kruppii.
off Angola, off St. Helena Is., G. of Guinea, off Morocco-Mauritania, Brazil (off Macaé), G. of Mexico, Sargasso Sea, Station "S" (32°10'N, 64°30'W), Arabian Sea, Laccadive Is., Maldive Is., off SW Sri Lanka, Indian, Andaman Sea, Indonesia-Malaysia, Philippines, China Seas (South China Sea), Japan (Izu, Hokkaido), Bering Sea ( S Aleutian Basin), Station Knot, Mariana Trench, off Hawaii E, Vancouver Is., California, off Galapagos, Peru, Pacif. (SE tropical), New Zealand.

Type locality: off San Diego (California).
N: 29
(5) F: 5,4; (10) F: 3,5; 3,7; (11) F: 4,98-4,26; (14) F: 4,65-4,6; (17) F: 4,3; (22) F: 4,3; (37) F: 4,98-3,7; M: 4,25; (40) F: 5,08-4,6; (113) F: 4,8-4,5; (137) F: 4,75; M: 4,25; (144) F: 3,7; (201) F: 4,75; {F: 3,50-5,40; M: 4,25}
Rem.: meso-abyssopelagic. Sargasso Sea: 1000-1500 m.
For Vervoort (1963 b, p.128) hesitates identified Wolfenden's G. rectus and Esterly's G. ascendens because the large discrepancies in size (G. rectus female: 3.50 mm; G. ascendens female: 3.70 mm); there is a great similarity in the shape of the head and the caudal part of the cephalothorax, while the development of the lamella on the coxa Mxp is almost identical in three species mentioned.
Bradford & Jillett (1980, p.48) examine the Wilson's material showing that G. curvispinus is identical with G. brevicornis from New Zealand (41°45'S, 174°55'E).
Observed for the first time by Dias & al. (2010) in Intermediate Antarctic water from off Macaé (S Brazil).
Last update : 23/11/2020
    to add your remark

 Any use of this site for a publication will be mentioned with the following reference :

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 25, 2024]

© copyright 2005-2024 Sorbonne University, CNRS

CNRS   Observatoire Océanologique de Banyuls sur Mer - Laboratoire Arago
Sorbonne Université


Version française
English version



On the WEB of CNRS


Marine Planktonic Copepods

Marine Planktonic Copepods


Imprimer Contact Accueil Plan du site Accès restreint Retour Une du Labo Imprimer Contact Plan du site Crédits Téléchargez les Plug-Ins