Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Scolecitrichidae ( Family )
            Amallothrix ( Genus )
Amallothrix gracilis  (Sars, 1905)   (F,M)
Syn.: Scolecithricella gracilis Sars, 1905 b (p.21, Rem.F); A. Scott, 1909 (p.93, figs.F); Sewell, 1948 (p.530); Tanaka, 1962 (p.60, figs.F,M, Rem.); Furuhashi, 1966 a (p.295, vertical distribution in Oyashio/Kuroshio transitional area, Table 8); Vives, 1982 (p.292); Shih & Young, 1995 (p.73); Lidvanov & al., 2013 (p.290, Table 2, % composition);
Scolecithrix globiceps Farran, 1908 b (p.54, Descr.F, figs.F);
Scaphocalanus globiceps : With, 1915 (p.199, figs.F,M; at 62°49' N)
Ref.:
Sars, 1925 (p.176, figs.F); Rose, 1933 a (p.152, figs.F); Jespersen, 1934 (p.89, fig.M); 1940 (p.37); Lysholm & al., 1945 (p.28); Sewell, 1947 (p.154, 161, Rem.); Owre & Foyo, 1967 (p.68, figs.F); Bradford, 1973 (p.143); Bradford & al., 1983 (p.78, 82, figs.F,M, Rem.); Vyshkvartzeva, 1999 (2000) (p.235); Vives & Shmeleva, 2007 (p.734, figs.F,M, Rem.)
Species Amallothrix gracilis - Plate 1 of morphological figuresissued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1962, X (1). [p.61, Fig.139]. As Scolecithricella gracilis.
Female (from Izu region): a, habitus (dorsal); b, forehead (lateral left side); c, last thoracic segment and urosome (lateral left side); d, rostrum (dorsal view); e, Mx2; f, Mxp; g, P1 (posterior aspect); h, P2; i, P5.
Mx2 has 5 small bud-like, and 3 long worm-like sensory filaments on the endopod.

Male: j, last thoracic segment and urosome (left lateral side); k, masticatory edge of Md; l, P5.

Nota Female:
- Head and 1st thoracic segment fused, pediger segments 4 and 5 incompletely fused, the line of fusion faintly visible in dorsal aspect.Lateral margin of the last thoracic segment rounded, but the posterior corner slightly produced.
- Cephalothorax and abdomen in the proportional lengths 78 : 22.
- Forehead narrowly rounded in dorsal aspect, but obtusely rounded when viewed from the lateral.
- Rostrum bifurcate, basal portion swollen and the terminal filaments tapers into fine point.
- Abdomen 4-segmented; Segments and caudal rami in the proportional lengths 42 : 23 : 17 : 4 : 14 = 100.
- Genital segment slightly produced ventrally.
- Abdominal segments 1 to 3 fringed with fine teeth on the distal border.
- Caudal rami 1.3 times as long as wide.
- A1 23-segmented; extends the end of the caudal rami by distal one segment.
- A2 exopod 1.1 times as long as endopod.
- Mx1 with 9 setae on the outer lobe; 9 setae on exopod; 8 setae on endopod; 5 setae on the 2nd basal; 4 setae on the 3rd inner lobe; 2 setae on the 2nd inner lobe; 12 setae on the 1st inner lobe (= praecoxal arthrite).
- Mx2 with 5 small bud-like, and 3 long worm-like sensory filaments on endopod.
- Mxp slender.
- P1 exopod 3-segmented, endopod 1-segmented. 1st exopodal segment with 1 outer edge spine which exceeds the distal margin of the 2nd exopodal segment.
- P2 with a moderately long and curved outer edge spine on the 1st exopodal segment; the 2nd exopodal segment has a double row of spinules near the distal border; terminal spine of exopod with 24 trrth.
- P3 with 19 teeth on the terminal exopodal spine.
- P5 not articulated. Inner marginal spine strong and coarsely serrated along anterior margin. Terminal spine about 194 the length of the inner marginal spine. Outer marginal spine small and arises opposite to the inner marginal spine. The segment furnished with 2 groups of spinules.

Nota Male:
- Cephalothorax about 2.83 length of abdomen.
- Head and 1st pediger segment incompletely fused (lige of fusion visible in the middorsal region), pediger segments 4 and 5 fused.
- Rostral filament rather short.
- Abdomen 5-segmented; segments and caudal rami in the proportional lengths 15 : 29 : 25 : 20 : 3 : 8 = 100.
- 2nd to 4th abdominal segments finely serrated on distal border.
- A1 21-segmented on the left side (segments 20 and 21 fused on the right side), reaches back to the end of abdomen.
- A2 exopod about 1.3 times as long as endopod. 1st basal segment with a tuft of hairs on posterior surface.
- Md with a broad 2nd basal segment; biting part slender.
- Mx2 as in female.
- Mxp slightly transformed.
- P1 to P4 as in female, but spinulation on the posterior surface of the various segments reduced.
- P5 long, exceeds the end of the caudal rami. In right leg the 1st exopodal segment has a triangular process on the inner margin about the middle of the segment; 2nd exopodal segment with a small triangular process on the outer distal corner; 3rd segment lanceiform. Endopod of the left leg 2-segmenyed, and shorter than the 3rd segmented exopod; distal segment provided with a small spine at apex.


Species Amallothrix gracilis - Plate 2 of morphological figuresIssued from : J.M. Bradford, L. Haakonssen & J.B. Jillett in Mem. N.Z. oceanogr. Inst., 1983, 90. [p.84, Fig.47].
Female: A, habitus (lateral left side); B, endopod of P2; C, P5; D, P5 (specimem from another station).

Male: F, P5


Species Amallothrix gracilis - Plate 3 of morphological figuresIssued from : G.O. Sars in Résult. Camp. Scient. Prince Albert I, 69, pls.1-127 (1924). [Pl.XLIX, figs.9-21]. As Scolecithrix gracilis.
Female: 9, habitus (dorsal); 10, idem (lateral left side); 11, rostrum; 12, A2; 13, Md; 14, Mx2; 15, distal segments of Mx2, with bud-like setae (enlarged); 16, Mxp; 17, P1; 18, P2; 19, P3; 20, P4; 21, P5.

Nota Female (as Amallothrix gracilis) :
- Rotrum prominent, strongly notched asfar as base in two narrow points endind in two filaments.
- Posterolateral corner of last thoracic segment not salient and rounded at apex.
- A1 lond about the body length.
- 4th and 5th pediger segments completely fused .
- Cephalothorax about 3 times the length of urosome.
- Genital segment length lesser than the succeeding two segments together, slightly swollen in its proximal part.
- Caudal rami slightly longer than wide and little divergent; second inner seta the longes, more longer than urosome.
- A1 24-segmented.
- A2 with exopod and endopod almost of the same length.
- Mx2 with 5 lobes from the same length on the basal segment; distal part with 3 sensory filaments, long and simple, and 5 shorter filaments bud-like (or amalla).
- P5 with 2 transverse rows of rigid hairs. The end of the segment slightly conical with 3 spines of unequal length, one inner very strong and thick , another much shorter at apex, a very little spine (tooth-like)on the outer margin, opposite to the inner spine.


Species Amallothrix gracilis - Plate 4 of morphological figuresissued from : R.B.S. Sewell in The John Murray Expedition, 1933-34, Scientific Reports, VIII (1), 1947. [p.162, Fig.43].
Female (from Central part of Arabian Sea): A, A2; B, Mxp; C, P2; D, P3; E, proximal part of P4; F, P5.
Nota: The number of setae from the various parts of Mx1: outer lobe (-); inner lobe 1 (12), inner lobe 2 (2), inner lobe 3 (4): basal segment 2 (5); endopod (8); exopod (9).


Species Amallothrix gracilis - Plate 5 of morphological figuresissued from : A. Scott in Siboga-Expedition, 1909, XIX a. [Plate XXXI, Figs.10-18]. As Scolecithricella gracilis.
Female (from Halmahera Sea): 10, habitus (dorsal); 11, forehead (lateral); 12, last thoracic and genital segments (left side); 13, rostrum; 14, A1; 15, Mx2 (distal portion); 16, P2; 17, P4; 18, P5.


Species Amallothrix gracilis - Plate 6 of morphological figuresissued from : G.P. Farran in Fish. Ire. Sci. Invest., 1906, II [1908]. [Pl. V, Figs.8-13]. As Scolecithrix globiceps.
Female (from W Ireland): 8, P1; 9, P2; 10, Mx1 (terminal part); 11, Mxp; 12, Mx2; 13, habitus (dorsal).


Species Amallothrix gracilis - Plate 7 of morphological figuresissued from : G.P. Farran in Fish. Ire. Sci. Invest., 1906, II [1908]. [Pl. VI, Fig.8]. As Scolecithrix globiceps.
Female: 8, P5.


Species Amallothrix gracilis - Plate 8 of morphological figuresissued from : C. With in The Danish Ingolf-Expedition, Copepoda I, 1915, III, 4. [p.199, Text-fig. 63]. As Scaphocalanus globiceps.
Female (from 61°30'N, 17°08'W): a, forhead (lateral); b, corner of the last thoracic segment and genital segment (right lateral).


Species Amallothrix gracilis - Plate 9 of morphological figuresissued from : C. With in The Danish Ingolf-Expedition, 1915, III (4). [Pl. VII, Fig.10, a-b]. As Scaphocalanus globiceps.
Female: a, labrum (oral surface); b, serrula 6-dentata.


Species Amallothrix gracilis - Plate 10 of morphological figuresissued from : C. With in The Danish Ingolf-Expedition, 1915, III (4). [Pl. VII, Fig.11, b]. As Scaphocalanus globiceps.
Male: b, P5.


Species Amallothrix gracilis - Plate 11 of morphological figuresissued from : C. With in The Danish Ingolf-Expedition, 1915, III (4). [Pl. VIII, Fig.9, a-c]. As Scaphocalanus globiceps.
Male: a, right P5; b-c, right P5 (endopodite in anterior and posterior view).


Species Amallothrix gracilis - Plate 12 of morphological figuresissued from : H.B. Owre & M. Foyo in Fauna Caribaea, 1, Crustacea, 1: Copepoda. Copepods of the Florida Current. [p.68, Figs.439, 440].
Female: 439, rostrum; 440, habitus (lateral).


Species Amallothrix gracilis - Plate 13 of morphological figuresissued from : H.B. Owre & M. Foyo in Fauna Caribaea, 1, Crustacea, 1: Copepoda. Copepods of the Florida Current. [p.24, Figs.105, 106].
Female: 105, distal segment of Mx2; 106, P5.

Nota: P5 unisegmented.


Species Amallothrix gracilis - Plate 14 of morphological figuresissued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1962, X (1). [p.61]. As Scolecithricella gracilis.
Female: Proportional lengths of segments of left A1.


Species Amallothrix gracilis - Plate 15 of morphological figuresissued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1962, X (1). [p.62]. As Scolecithricella gracilis.
Male: Proportional lengths of segments of left A1.
Nota: segments 20 and 21 are fused on the right side.

Compl. Ref.:
Sewell, 1948 (p.330, 502, 521, 546); C.B. Wilson, 1950 (p.161); Mazza, 1966 (p.71); Grice & Hulsemann, 1967 (p.16); Deevey & Brooks, 1977 (p.256, tab.2, Station "S"); Kovalev & Shmeleva, 1982 (p.84); Suarez & al., 1990 (tab.2); Suarez, 1992 (App.1); Suarez-Morales & Gasca, 1998 a (p.111); Holmes, 2001 (p.57); Kuriyama & Nishida, 2006 (p.299: Tab;II; p.306: Tab.III, fig.7); Morales-Ramirez & Suarez-Morales, 2008 (p.522)
NZ: 12

Distribution map of Amallothrix gracilis by geographical zones
Loc:
Brazil (in Björnberg, 1965), Morocco-Mauritania, off Madeira, off Portugal, Azores, Caribbean Sea, G. of Mexico, Florida, off Bermuda (Station "S"), Sargasso Sea, off W Ireland, Davis Strait, S Iceland, Medit. (Alboran Sea, W Basin, G. of Sidra), Arabian Sea, Indian, Indonesia-Malaysia, Philippines, China Seas (South China Sea), Japan (Izu), W Costa Rica, Galapagos, Peru, New Zealand
N: 28
Lg.:
(1) F: 4,25; (5) F: 4; (7) F: 4,48; M: 4,44; (9) F: 4,1-3; M: 3,95-3,3; (24) F: 4,5-4,3; (117) F: 4,13; M: 4,06; (1000) F: 4,2 ±0,2; {F: 3,00-4,50; M: 3,30-4,44}
Rem.: meso-bathypelagic. Sargasso Sea: 1000-1500 m (Deevey & Brooks, 1977, station "S").
Sewell is doubtful wether the form described by A. Scott (1906) is actually of this species contrary to Tanaka (1962, p.62).

For Sars (1925, p.179) this species resembles much to Amallothrix propinqua except P5 which show in the latter a structure bisegmented and and without spine on the outer margin.
Last update : 21/03/2017
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