Species Card of Copepod
Calanoida ( Order )
    Clausocalanoidea ( Superfamily )
        Aetideidae ( Family )
            Bradyidius ( Genus )
Bradyidius similis  (Sars, 1902)   (F,M)
Syn.: ? Bradyanus armatus Vanhöffen, 1897 a (p.280, figs.); Mrazek, 1902 (p.521);
Undinopsis similis Sars,1902 (1903) (p.34, figs.F,M); Sars, 1925 (p.44); Rose, 1933 a (p.92, figs.F,M); Kovalev & Schmeleva, 1982 (p.83); Mikhailovsky, 1986 (p.83, Table 1, ecological modelling); Gaard & al., 2008 (p.59, Table1, N Atlantic Mid-Ridge);
Undinopsis armatus : Vanhöffen, 1907 (p.517, Pl.21: fig.24, Pl.22: figs.28-30); With, 1915 (p.88, Rem.)
Vervoort, 1952 b (n°43, p.3, figs.F,M); ? C.B. Wilson, 1950 (p.173, fig.M); Park, 1966 (p.810, Rem.F,M); Bradford, 1976 a (p.6: Rem.); Shih & al., 1981 (p.1079, figs. F,M, juv.); Gardner & Szabo, 1982 (p.208, figs.F,M); Othman & Greenwood, 1987 (p.1137); Markhaseva, 1996 (p.79, figs.F,M); G. Harding, 2004 (p.42, figs.F,M); Yamaguchi & al., 2005 (p.835, Tabl. VIII)
Species Bradyidius similis - Plate 1 of morphological figuresissued from : E.L. Markhaseva in Trudy Zool. Inst. RAN, St. Petersburg, 1996, 268. [p.83, Fig.60].
Female. P.md: mandibular palp; R: rostrum (anterior).

Nota: Cephalothorax 3.2-3.3 times longer than urosome.
Rostrum with slightly divergent rami (in some specimens nearly non divergent).
Points of last thoracic segment reaching or exceeding the midlength of genital segment.
A1 24-segmented, reaching nearly the end of cephalothorax.
Mx1 gnathobase with 4 posterior setae; endopd with 15-17 setae; 2nd internal lobe of Mx1 with 4 setae (5 for Shih & al., 1981).

Species Bradyidius similis - Plate 2 of morphological figuresissued from : E.L. Markhaseva in Trudy Zool. Inst. RAN, St. Petersburg, 1996, 268. [p.84, Fig.61].
Male. Ce: forehead (lateral); R: rostrum (anterior).

Nota: Right A1 23-segmented; left 24-segmented, reaching urosomal segment 4; penultimate segment of right A1 with group of denticles.
Oral parts rudimentary compared to those of females.
Exopod of left P5 2-segmentd; right P5 3-segmented.

Species Bradyidius similis - Plate 3 of morphological figuresissued from : G.O. Sars in An Account of the Crustacea of Norway. Vol. IV. Copepoda Calanoida. Published by the Bergen Museum, 1903. [Pl.XXI]. As Undinopsis similis.
Female & Male.
pr = corner of the last thoracic segment; M = Md (mandibular palp).

Species Bradyidius similis - Plate 4 of morphological figuresissued from : C.-t. Shih, L. Rainville & D.C Maclellan inCan. J. Zool., 1981, 59 (6). [p.1089, Figs.79-92].
Female (from Saguenay fjord and adjacent waters of the St. Lawrence River): 79-80, habitus (dorsal and lateral, respectively); 81, rostrum (frontal view); 82, same (lateral); 83, A1; 84, A2; 85, Md and enlarged distal part of gnathobase); 86, Mx1; 87, Mx2; 88, Mxp; 89-92, P1 to P4.
Scale A for appendages; scale B for figs 79-80.

Species Bradyidius similis - Plate 5 of morphological figuresissued from : C.-t. Shih, L. Rainville & D.C Maclellan inCan. J. Zool., 1981, 59 (6). [p.1090, Figs.93-108].
Male: 93-94, habitus (dorsal and lateral, respectively); 95, rostrum ( frontal view); 96, same (lateral); 97, anal somite and caudal rami (dorsal); 98, A1; 99, A2; 100, Md (gnathobase entirely degenerated); 101, Mx1; 102, Mx2; 103, Mxp; 104-108, P1 to P5.
Scale A for appendages and rostrum; B for figs.93-94 and 97.

Nota: left A1 24-segmented; right 23-segmented (segments 8-9, 20-21 fused), reaching nearly to posterior margin of 3rd thoracic segment. 1st thoracic segment completely fused with cephalosome. A2 exopod slightly longer than endopod. Md exopod 4-segmented with 3 terminal setae; gnathobase degenerated. Mx1 reduced in size, segmentation and armature; 1st outer lobe with 5 setae; exopod not reduced, with 10 setae; endopod 2-segmented with 4 and 5 setae respectively; 1st inner lobe degenerated, 2nd inner lobe reduced, with 3 terminal setae and a few spinules on medial and lateral margins, 3rd inner lobe reduced to a small process without setae. Mx2 reduced to a narrow lobulated structure with 2 small setae at distal end. P1 to P4 similar to those of female. Urosome 5-segmented, anal somite very short.

Species Bradyidius similis - Plate 6 of morphological figuresissued from : G. Harding in Key to the adullt pelagic calanoid copepods found over the continental shelf of the Canadian Atlantic coast. Bedford Inst. Oceanogr., Dartmouth, Nova Scotia, 2004. [p.42].
Female & Male.

Female with rostrum deeply bifurcate; last thoracic segment with spines thick at base.

Species Bradyidius similis - Plate 7 of morphological figuresBradyidius similis female: 1 - Rostrum with divergent rami.
2 - Points of last thoracic segment not reaching posterior border of genital segment. Exopodal segment 2 of A2 with 2 setae. Exopodal segment 1 of P1 with external spine not reaching the base of external spine of segment 2.
3 - Posterior corners of last thoracic segment nondiverging.
4 - Rostral rami sligtly divergent (compare with B. saanichi), acute angle in their base.

Species Bradyidius similis - Plate 8 of morphological figuresBradyidius similis male: 1 - P5 biramous.
2 - Endopod of left P5 1-segmented.
3 - Points of last thoracic segment reaching or even exceeding posterior urosomal segment 1.

Compl. Ref.:
Maclellan D.C., 1967 (p.101, 102: occurrence); Shih & al., 1971 (p.32, 143); Tremblay & Anderson, 1984 (p.3, Rem.); Shih & Marhue, 1991 (tab.3); Sirenko & al., 1996 (p.345); Markhaseva, 1998 (p.250, Fig.2); Bradford-Grieve, 2004 (p.283); Blachowiak-Samolyk & al., 2006 (p.101, tab.1); Blachowiak-Samolyk & al., 2008 (p.2210, Table 3, as similles, biomass); Hop & al., 2006 (p.182, Table 4); Galbraith, 2009 (pers. comm.); Dvoretsky & Dvoretsky, 2010 (p.991, Table 2); Kosobokova & al, 2011 (p.29, Table 2, 3, Rem.: Arctic Basins)
NZ: 7 + 2 doubtful

Distribution map of Bradyidius similis by geographical zones
North Sea, Norway, Barents Sea, Greenland, Kongsfjorden, Spitzbergen, Laptev Sea, Nansen Basin, NE Atlant., Azores, E Medit. (Ionian Sea), G. of Maine, Nova Scotia, G. of St. Lawrence, Saguenay Fjord, Baie des Chaleurs, Ameralik & Godthaab fjords (W Greenland), Bering Sea, Okhotsk Sea, Queen Charlotte Is., British Columbia, ? Philippines (in C. B. Wilson, 1950)
N: 22
(37) F: 3,24-2,84; M: 2,77-2,4; (65) F: 3; M: 2,4; {F: 2,84-3,24; M: 2,40-2,77}
Rem.: neritic, hyperbenthic, mesopelagic.
The identification from the Philippines seems doubtful and needs confirmation.
Its observation in the Mediterranean Sea needs confirmation.
Last update : 12/11/2018
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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 30, 2024]

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Marine Planktonic Copepods

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