Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Scolecitrichidae ( Family )
            Amallothrix ( Genus )
Amallothrix falcifer  (Farran, 1926)   (F,M)
Syn.: Scolecithrix falcifer Farran, 1926 (p.262, Descr.F, figs.F); Bradford, 1973 (p.143)
Rose, 1933 a (p.155, figs.F); C.B. Wilson, 1950 (p.160, fig.F); Roe, 1975 (p.325, Redescr.F,M, figs.F,M); Park, 1980 (p.51, Rem.); Bradford & al., 1983 (p.78, Rem.); Vyshkvartzeva, 1999 (2000) (p.235); Vives & Shmeleva, 2007 (p.726, figs.F,M, Rem.)
Species Amallothrix falcifer - Plate 1 of morphological figuresissued from : G.P. Farran in Biscayan Plankton collected during a Cruise of H.M.S. 'Research', 1900.- Part XIV. The Copepoda. (Linn. Journ. Zoology, XXXVI, 1926). [p.304, Pl.8, Figs.9-14]. As Scolecithrix falcifer.
Female: 9, habitus (dorsal); 10, last thoracic segment with P5 and urosome (lateral); 11, A2; 12, P2; 13, P3; 14, P5.

Species Amallothrix falcifer - Plate 2 of morphological figuresissued from : H.S.J. Roe in Bull. British Mus. (Natural History) Zool., London, 1975, 28 (7). [p.326, Fig.15a-m].
Female (NE Atlantic): habitus (dorsal); b, forehead and rostrum (right lateral side); c, last thoracic segment and urosome (right lateral side); d, A2; e, mandibular palp; f, Mx1; g, Mx2; h, Mx2 (brush-like seta head); i, P1; j, P2; k, P3; l, P4; m, P5.
Bar scale 0.1 mm unless indicated.
Nota: Forehead rounded with 2 rostral filaments thickened over most of their length.
Cephalothorax 3.8 times as long as the 4-segmented abdomen.
Head and 1st thoracic segment fused, 4th and 5th fused. A1 23-segmented, reaches back to the anal segment.
Mxp with a sensory seta in the middle of the 1st basipodite.
Mx2 with 5 brush-like setae on the endopodite and at least 2 ribbon-like setae.
The hind margin of the cephalothorax slightly indented.
Internal edge of the 2nd basipodite of P2 with a characteristic group of spines.
Surface of P2 and P3 heavily ornamented with spines.
Genital segment almost as long as the combined length of the three subsequent segments.
Caudal rami only slightly longer than wide.

Species Amallothrix falcifer - Plate 3 of morphological figuresissued from : H.S.J. Roe in Bull. British Mus. (Natural History) Zool., London, 1975, 28 (7). [p.326, Fig.15n-r].
Male (NE Atlantic): n, habitus (dorsal); o, Mx2 (endopod); p, P5; q, P5 (last exopodite segment right leg); r, P5 (terminal segments left leg).

Bar scale 0.1 mm unless indicated.
Nota: Cephalothorax 3 times longer than the 5-segmented abdomen.
Head and 1st thoracic segment fused, 4th and 5th fused.
A1 19-segmented, reaches back to the hind edge of the 3rd abdominal segment.
Exopodite of A2 with 3 terminal setae, 1st endopodite segment with a brunch of hairs.
Mx1 slightly variable; in one specimen the 1st outer lobe has 8 setae, in another the 3rd inner lobe has 3, and in both the 2nd basipodite has 5 and the 1st endopodite has 3 setae.
Mx2 lobes 2-5 each has an enlarged seta typical of other Amallothrix males and the endopodite has 5 brush-like setae and 3 ribbon-like setae; two of the brush-like setae are short and one of these is conspicuously larger than the others.
Swimming legs identical to those of females.
P5 reaches back to the end of the abdomen; on the right leg the endopod is a short single segment and the last exopodite segment is leaf-shaped; on the left leg the endopod ends in a flagellum and the 3rd exopodite segment has a row of setae and a lamella.

Compl. Ref.:
Grice, 1963 a (p.495); Grice & Hulsemann, 1965 (p.223); Mazza, 1966 (p.71); Harding, 1974 (p.141, tab. 3, gut contents); Soenen, 1974 (p.120); Deevey & Brooks, 1977 (p.256, tab.2, Station "S"); Vives, 1982 (p.292); Kovalev & Shmeleva, 1982 (p.84); Echelman & Fishelson, 1990 a (tab.2); Gaard & al., 2008 (p.59, Table 1, N Mid-Atlantic Ridge); Belmonte, 2018 (p.273, Table I: Italian zones)
NZ: 5

Distribution map of Amallothrix falcifer by geographical zones
Cape Verde Is., off Mauritania, off W Canary Is., Bay of Biscay, Azores, G. of Mexico, off Bermuda (Station "S"), off E Cape Cod, W Medit. (Algiers Bay, Sardinia , Strait of Sicily, S Adriatic Sea), Red Sea (G. of Aqaba), Philippines (in C.B. Wilson, 1950, p.160)
N: 14
(8) F: 2,2-1,8; M: 2,81-1,98; (38) F: 2; {F: 1,80-2,20; M: 1,98-2,81}
Rem.: bathypelagic. Sargasso Sea: 1500-2000 m (Deevey & Brooks, 1977, station "S"); In vertical tow 4000-3000 m (Harding, 1974).
For Roe (1975, p.327) there are, apparently, two size groups in the males. Two specimens each measured 1.98 mm but the remaining seven were between 2.58 and 2.81 mm in length. There are no structural differences between the large and small specimens.
Last update : 06/02/2020
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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 15, 2024]

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