Copyright: Per Hoffmann Olsen

Cordulegaster bidentata (Selys, 1843)

Cordulegaster bidentata

Flight-period Central Europe: from June to August

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Imago

Conservation Status in Austria: Vulnerable (VU)

  NE DD LC NT VU EN CR RE EX
Austria
Europe

English:Sombre Goldenring
German:Gestreifte Quelljungfer
Danish:
Date:17/07/2017
Location:Austria, Niederösterreich, Ober-Danegg
 
Copyright:Per Hoffmann Olsen
Camera:Canon EOS 50D
Lens:Sigma 150mm 1:2.8 APO Macro
 

Identification Help

The root triangle on the backwings have 5 cells instead of 3, which could make it C. boltonii instead of C. bidentata. But according to this document http://www.libellula.org/wp-content/uploads/2016/10/30_1-2_Pix_a.pdf there is about 3% possibility that it is the C. bidentata, when looking on the backwing cells alone. They do variate from 2 to 6 cells where 3 cells is the most common.

Cordulegaster_bidentata_D_290717C.gif

But before concluding that its a C. boltonii you have to look at two other characteristics of the C. boltonii, first: that the triangle behind the eyes is yellow instead of black like on the C. bidentata - here it seems to be black.

Second: The C. boltonii also has a weak very fine second set of yellow stripes on the abdomen - which seems to be missing here as well. 

So this must be the C. bidentata.

More information information on the C. boltonii here: https://www.natur-in-nrw.de/HTML/Tiere/Insekten/Libellen/TL-26.html (in German)

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