Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Phaennidae ( Family )
            Xanthocalanus ( Genus )
Xanthocalanus claviger  (T. Scott, 1909)   (M)
Syn.: Amallophora claviger T. Scott, 1909 (p.124, Descr.M, figs.M)
With, 1915 (p.239, figs.M, Rem.); Sewell, 1948 (p.501); Bradford & al, 1983 (p.71)
Species Xanthocalanus claviger - Plate 1 of morphological figuresissued from : T. Scott in Ann. Mag. nat. Hist., 1909, 8 (3). [Pl.III, Figs.1-11]. As Amallophora claviger.
Male (from 59°36'N, 07°W): 1, habitus (lateral); 2, rostrum (frontal view); 3, A1; 4, A2; 5, Md (mandibular palp); 6, distal portion of Mx2; 7, Mxp; 8, P1; 9, P2; 10, P3; 11, P4.

Nota: A1 25-segmented (1st and 2nd segments somewhat dilated, the next four small, subequal, the 6th to the 12th more or less coalescent, 13th and 14th small, the 15th to 19th rather longer than the precedin two segments or those that follow; proportional lengths of successive segments: 1 (17), 2 (12), 3 (7), 4 (8), 5 (7), 6 (8); 7-12 (38), 13 (9), 14 (9), 15 (14), 16 (15), 17 (16), 18 (15), 19 (15), 20 (12), 21 (9), 22 (8), 23 (11), 24 (11), 25 (6). Endopod of A2 much shorter than exopod. gnathobase of Md small, narrow, elongated, distal end somewhat constricted, biting end obliquely truncated and armed with small denticles. Mx2 small, furnished with a dense fascicle of sensory filaments and a number of setae. Mxp small, elongated, and sparingly setigerous. The P1 to P4 somewhat similar to those in Sars.

Species Xanthocalanus claviger - Plate 2 of morphological figuresissued from : T. Scott in Ann. Mag. nat. Hist., 1909, 8 (3). [Pl.IV, Figs.13-17]. As Amallophora claviger.
Male: 13, Md (masricatory blade); 14, P5; 15, end segment of long branch of P5 (enlarged); 16, idem (another view); 17, urosome.

Species Xanthocalanus claviger - Plate 3 of morphological figuresissued from : C. With in The Danish Ingolf-Expedition, Copepoda I, 1915, III, 4. [p.239, Text-fig. 78].
Male (from 61°30'N, 17°08'W): a, last thoracic segment with P5 and urosome (lateral); b, left P5 (exopodal segments 2 and 3 in situ from left side); c, left P5 (exopodal segments 2 and 3 in anterior view); d, right P5 (exterior view).

Nota : Head without crest.
Head and pedigerous segment 1 fused, 4th and 5th fused.
Prosome 2.4 as long as the urosome. Posterior margins of urosomal segments poorly serrated.
A1 extend to the end of the 2nd urosomal segment. Segments 8-9 are only in front indistinctly separated from segments10-12, which are completely fused ; these segments are fairly well separated from segment 13, which is well separated from segment 14 ; the following segments are well separated from each other ; a complete ‘’trithek’’ is found in segments 3-9 ; aesthetascs are found in segments 10-19, but are wanting in segments 20-24 ; small proximal setae are seen in segments 12, 14, 16 and 18.
Exopodite of A2 1.5 as long as the endopodite, which has 6 setae in the outer lobe and 8 in the inner lobe of the 2nd segment.
The manducatory part of M dis soft-skinned and very long and slender, with delicate but distinct teeth.
Mx1 : the outer lobe has 7 long powerful and 2 short btristles ; the innerlobe is only a little longer than wide, with at least 9 bristles, which are long, broad, somewhat lamellous and distinctly plumous ; the inner lobe 2 has 4 short setae ; the inner lobe 3 has 4 fiarly long, partly plumous setae ; the 3rd lobe has 5 setae. The endopodite seems only to possess 10 setae, and so does the exopodite.
Mx2 : ratther soft-skinned ; the 1st lobe has 4 rather slender setae, the lobe 2-3 have 3 each ; the 4th lobe has 2 slender plumous bristles and a long, broad, strongly plumous seta, the 5th lobe has a single shorter one of similar structure in addition to 2 fairly strong plumous setae and a very delicate one. The endopodite has 2 vermiform setae, 5 rather slender brush-shaped ones, and a curious globular appendage scarcely twice as long as wide, with terminal almost circular opening and striated wall.
Mxp scacely different from those of X. borealis.
P5 extends beyond the end of urosome. Right P5 short and somewhat convex outwards, but extends distinctly beyond the end of the 1st basal segment ; it consists of 4 segments, of which the last one shows trace of further segmentation, and is terminated with a short tooth. Left P5 consists of 3 elongated proximal segments, 1st segment has inwards on the anterior surface a short keel fig.a-c) ; the 4th segment is much shorter than the preceding ones, an dis somewhat enlarged towards the middle, where a process with 2 groups of about 10 bristles, beyond this process the segment is hollowed with a concavity facing inwards, and has about 6 setae along the outer margin, as well as a tuft of 5 more slender ones and 1 stronger seta terminally (fig.b,c), apparently articulated to this segment a short’’segment’’ with a tuft of hairs ; the terminal segment has along the one margin in the middle 5 fairly strong spines, and terminally a hooked spine, at the base of which 4 moderately slender setae.

NZ: 2

Distribution map of Xanthocalanus claviger by geographical zones
N Scotland, S Iceland
N: 2
(7) M: 4,55; {M: 4,55}
Rem.: For With (1915, p.240) the male of this species, especially characterized by the curious development of the left P5, is identical with Scott's Amallophora claviger.
Last update : 02/02/2015
    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 July 20, 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