Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Aetideidae ( Family )
            Bradyidius ( Genus )
Bradyidius angustus  (Tanaka, 1957)   (M)
Syn.: Undinopsis angustus Tanaka, 1957 a (p.45, Descr.M, figs.M)
Bradford, 1976 a (p.6: Rem.); Othman & Greenwood, 1987 (p.1137); Markhaseva, 1996 (p.70, figs.M); Chihara & Murano, 1997 (p.683, Pl.27: M); C.-Y. Lee & al., 2009 (p.151, Tab.2); Lim & al., 2011 (p.39, Redescr.M, figs.M, Rem.)
Species Bradyidius angustus - Plate 1 of morphological figuresissued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1957, VI (1). [p.46, Fig.29]. As Undinopsis angustus.
Male: a, habitus (dorsal); b, forehead (lateral); c, last thoracic segment (lateral); d, rostrum; e, A2; f, P1; g, P2; h, P4; i, P5.
Nota: Head and 1st thoracic segment fused, 4th and 5th fused. Proportional lengths of urosomites and furca 14:32:19:19:3:13 = 100. A1 extends to distal margin of 2nd urosomal segment. Mx2 much reduced.

Species Bradyidius angustus - Plate 2 of morphological figuresissued from : B.-J. Lim, Song S.J. & Min G.-S. in Korean J. Syst. Zool., 2011, 27 (1). [p.40, Fig.4].
Male (from 36°05'N, 131°40'E): A, habitus (dorsal); B, rostrum (frontal view); C, A1; D, A2; E, Md; F, Mx1; G, Mxp.
Scale bars: 0.5 mm (A); 0.1 mm (D , E, G); 0.05 mm (B).

Nota : Prosome about 2.3 times as long as urosome.
Cephalosome and 1st pedigerous somite fused.
Posterior corners of last pedigerous somite extending to distal margin of 1st abdominal somite.
Rostrum bifurcate and weakly divergent.
A1 22-segmented, reaching posterior border of genital somite.
Md : Basis with 2 short setae. Endopodal segment with 8 setae. Exopod indistinctly 4-segmented, 1st segment unarmed.
Mx1 : Arthrite unarmed. Coxal endite degenerate. Coxal epipodite with 4 large and 1 minute setae. Basal endites with 1, 2 setae respectively. Endopod with 9 setae. Exopod with 7 setae.
Mx2 strongly reduced in size and structure.
Mxp : Coxa with 1distal seta. Basis with 2 medial setae. Endopod 6-segmented, 1st segment with 1 seta, 2nd to 6th segments with 4, 3, 2+1, 2, and4 setae respectively.

Species Bradyidius angustus - Plate 3 of morphological figuresissued from : B.-J. Lim, Song S.J. & Min G.-S. in Korean J. Syst. Zool., 2011, 27 (1). [p.41, Fig.5].
Male: A-C, P1 to P3; D, P5.
Scale bar: 0.1 mm (A-D).

Nota : P5 uniramous and asymmetrical. Right and left exopod without seta and spine ; 3rd segment of right exopod spiniform, about 2.4 times longer than 2nd segment ; 3rd segment of left exopod forming a sharp process with 1 subdistal seta.

Species Bradyidius angustus - Plate 4 of morphological figuresissued from : B.-J. Lim, Song S.J. & Min G.-S. in Korean J. Syst. Zool., 2011, 27 (1). [p.42].
Male: Armature formula of swimming legs P1 to P3 (P4 missing).
Roman numerals = spines; Arabic numerals = setae.

Compl. Ref.:
Markhaseva, 1998 (p.250, Fig.2)
NZ: 2

Distribution map of Bradyidius angustus by geographical zones
E Korea, Japan (Sagami, Suruga), NW Taiwan
N: 4
(39) M: 1,37; (1090) M: 1,57; {M: 1,37-1,57}
Rem.: Mesopelagic.
Last update : 07/01/2020
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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 May 25, 2024]

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