Dear Rudi,

I think this should be Stictoleptura scutellata (Fabricius, 1781). Compare the shape and outline of the elytra.

http://www.cerambyx.uochb.cz/melascut.htm

Best,

Fabian

Thank you very much, Fabian.

I tried to retrace this with FHL and I could see my failure. Supplemementary, Acmaeops septentrionis has hairy elytra and is also much smaller than St. scutella. What the picture also shows, is the "rough dotted anterior third of the elytra getting more fine to the apex". 

Best wishes

Rudi

Hi Rudolf and Fabian,

I can't see any characters leading to S. scutellata except the black color...  If you compare the "rough dotted anterior third of the elytra" with other pictures of S. scutellata you can find, you will see that your specimen isn't roughly dotted at all. Plus, I've never seen scutellata with a black scutellum, but I heard it's possible sometimes. The light makes it very hard to see the shape of the elytral apex, so really I wouldn't be sure, but maybe you have another picture for that character ?

Could be Letpura aethiops instead ?

Dear Vincent,

Leptura aethiops is of course a possibility and I agree with you that the typical roughly dotted anterior third of the elytra is not visible. However, the specimens of L. aethiops I have seen so far have been much more elongated and much narrower. I have also seen specimens of S. scutellata with black scutellum, yet I have to admit, these originated from Bulgaria and not from Germany.

Best,

Fabian

Hi Vincent and Fabian,

I'll have a look for other pictures, but they are not available at the moment. I think, Leptura aethiops is slimmer and has more curved tibiae at the hind legs. But I don't know if this are species-specific qualities.

I agree that most of L. aethiops look slimmer and elongated, although some large females are stout enough.

I'm not 100% convinced that this is L. aethiops, but I think this is not  S. scutellata either.

I'm investigating other possibilities but a detailled picture of the elytral apex would be of great help.

How about Pedostrangalia pubescens? The dark form obviously, female.

Hi Anders,

We would need a better view of the hind angles of the pronotum to be sure, but here shoulders seem distinctly wider than prothorax, which is not the case for P. pubescens because of its big and acute pronotal posterior angles. 

Could the size of the insect be a discriminating characteristic? Can you tell something about its length? Regards,

Rinaldo

Hello Rinaldo,

to your additional questions: I don't know the real size, but I would estimate it at about 20 mm.

Hello Vincent,

I tried to magnify the hind angles of the pronotum and the elytral apex.

Hello Anders,

Pedostrangalia pubescens is not listed in my key (FHL); I know this species only from "Folia Heyrovskyana", which is no key, there are only very good pictures. Only the male specimen is mapped (as Etorufus pubescens). At all, the shape would fit.

Thank you all for the motivated discussion! Ok, I know what I have to do next year: I have to collect one specimen of this beetle!

Rudi

Hello Rinaldo,

to your additional questions: I don't know the real size, but I would estimate it at about 20 mm.

Hello Vincent,

I tried to magnify the hind angles of the pronotum and the elytral apex.

Hello Anders,

Pedostrangalia pubescens is not listed in my key (FHL); I know this species only from "Folia Heyrovskyana", which is no key, there are only very good pictures. Only the male specimen is mapped (as Etorufus pubescens). At all, the shape would fit.

Thank you all for the motivated discussion! Ok, I know what I have to do next year: I have to collect one specimen of this beetle!

Rudi

Thanks; if you have no other view it's impossible for me to be 100% sure but I still think its a female of Leptura aethiops (like this one http://www.biolib.cz/en/image/id41474/ ) .

Collecting one specimen is always a good a idea to get species level so indeed you know what you have to do next summer :)

My suggestion is to get a series.  You'll have a better chance at species identification.  Some characters tend to be variable (ie:  "ususally", "sometimes", "often" being not uncommon in keys).

Acmaeops septentrionis

Leptura cf. aethiops (surely NOT Acmaeops)

 I think everything has been said already. Just giving a wrong identification with no argument won't help :)

Although it's very difficult to identify a species from a pictures, I'm quite sure that your specimen is a female of Anastrangalia dubia, black form.

Regards...

Indeed that would be possible too. From this 2 pictures only I find it very hard to tell. I preferred Leptura aethiops because of what I can see from the elytral apex, but the stoutness could be in favour of Anastrangalia.

I have collected hundreds of specimens of Anastrangalia dubia for studies on pollination in the Alps, and I've never seen such a dark form so it seems very rare there, but maybe not in Germany ?

In this case pictures aren't enough to give a 100% certain ID I think.

 Leptura aethiops female, without any doubts.

Thank you very much all for your inputs!

Indeed it must be very rare also here where I found it, because I am often on this place and I saw this species only once!

This species is increasingly rare in Luxembourg as well, though small series of 4-5 specimens wee found in Elsaß and Saarland until a few time ago. I could only collect single specimens, only 3 times in different localities, in 7 years of field research throughout the country.