Onchocalanus cristogerens - Species Card - Marine Planktonic Copepods

Species Card of Copepod

Calanoida ( Order )	details
Clausocalanoidea ( Superfamily )	details
Phaennidae ( Family )	details
Onchocalanus ( Genus )	details	List species for this Genus

Onchocalanus cristogerens Markhaseva & Kobosokova, 1998 (M)

Abbreviations or symbols

Syn.:

Onchocalanus cristatus : Harding, 1966

Ref.:

(

List of the studied authors )

Markhaseva & Kobosokova, 1998 (p.48, Descr.M, figs.M)

Species Onchocalanus cristogerens - Plate 1 of morphological figures

issued from : E.L. Markhaseva & K.N. Kosobokova in Zoosyst. Ross., 1998, 7 (1). [p.49, Figs.22-31].
Male (80°55'N, 122°39'E): 22, anterior part of the body (lateral); 23, forehead (dorsal); 24, rostrum (frontal view); 25, pediger segment 5 and urosome (dorsal); 26, pediger segments 3-5 and urosome (lateral); 27, A2; 28, Md (mandibular palp); 29, Mx1; 30, Mx2; 31, Mxp.
Scale bars: 0.1 mm.

Nota : Prosome nearly 3.8 times as long as urosome. Crest moderately pronounced. Rostrum with thin fimaments terminally. Pediger segments 4 and 5 incompletely fused ; posterior corners of pediger segment 5 rounded in lateral view and triangular in dorsal view. A1 as long as body A2 exopodite 1-2 without seta, exopodite 7 with 3 long terminal setae. Md palp with 2 minute setae at the basis, endopodite 1 with 2 setae, endopodite 2 with 9 setae ; exopodite 1-4 segments with 1 seta each, exopodite 5 with 2 terminal setae. Inner lobe 1 setation reduced, without well developed spines ; inner lobe 2 without setae ; inner lobe 3 with 3 setae ; inner lobe 4 with 4 setae ; endopod with 8 setae ; exopod with 11 setae ; outer lobe 1 with 7 setae. Mx2 lobe 5 with 1 of 3 setae as spine-like ; distal part with 1 worm-like and 6 brush-like setae (probably 7th brush-like seta typical of Phaennidae is broken).

Species Onchocalanus cristogerens - Plate 2 of morphological figures

issued from : E.L. Markhaseva & K.N. Kosobokova in Zoosyst. Ross., 1998, 7 (1). [p.50, Figs.32-37].
Male: 32, P1; 33, P2; 34, P3 (incomplete); 35, P4 (incomplete); 36, P5; 37, right P5 and P5 left first segment.
Scale bars: 0.1 mm.

Nota : P5 uniramous ; left leg 5-segmented, slightly more than 2 times as long as urosome ; right leg 4-segmented, reaching the distal border of the 1st segment of the left leg.

Compl. Ref.:

(

List of the studied authors )

Kosobokova & Hirche, 2000 (p.2029, tab.2); Kosobokova & Hopcroft, 2010 (p.96, Table 1, fig.7); Kosobokova & al., 2011 (p.29, Table 2, Rem.: Arctic Basins)

NZ:

Distribution map of Onchocalanus cristogerens by geographical zones

Loc:

(

Geographical glossary )

Arctic (Canada Basin, Makarov Basin, Amundsen Basin, Nansen Basin)

Lg.:

(

References of the authors concerning dimensions )

(779) M: 5,1; {M: 5,10}

Rem.:

In vertical haul from Eastern Eurasian Basin: 3566-2000 m.
After Markhaseva & Kosobokova (1998, p.51) the genus Onchocalanus was registered in the Arctic Basin by Harding (1966) and Dunbar & Harding (1968) ; they referred to the species as Onchocalanus cristatus (Wolfenden, 1904), but mentioned : the form recorded in the Arctic Ocean has probably diverged somewhat and should be given a variety or other subspecific status. Comparison with the redescriptions of O. cristatus (Park, 1983 ; Tanaka, 1992) prove their supposal. Markhaseva & Kosobokova consider the Arctic form as a separate species. The shape and the rate of crest development distinguish O. cristogerens from O. cristatus and O. subcristatus.

Last update : 27/01/2015


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