Thread subject: :: Ulidiidae - Seioptera vibrans or Homalocephala biumbrata?

Posted by Marion Friedrich on 24-05-2022 22:11


I found this fast fly on a dead Aspen in a forest. Is species ID possible?

Thank you, Marion

Germany, Saxony, ca. 350 m, 22.05.2022.

Edited by Marion Friedrich on 24-10-2022 13:31

Posted by Marion Friedrich on 24-05-2022 22:12

2nd picture

Posted by Marion Friedrich on 08-07-2022 22:14

In the meantime I took some more fly photos on the same aspen which may be helpful for ID.

Posted by Marion Friedrich on 08-07-2022 22:17


Posted by Marion Friedrich on 08-07-2022 22:18


Posted by tristram on 09-07-2022 10:13

Maybe Ulidiidae

Posted by Jan Maca on 09-07-2022 11:11

Yes, I would say it is Seioptera vibrans.

Posted by Marion Friedrich on 09-07-2022 14:37

Thank you very much.
Seioptera vibrans seems to be variable in colour. I overlooked it in the gallery because of the relatively dark and less reddish frons of my flies.

Greetings, Marion

Posted by Marion Friedrich on 24-10-2022 13:38

I looked at Seioptera vibrans again. In the Seioptera vibrans pictures in the gallery veins R4+5 and M1 converge to the wing tip. In my pictures, the veins R4+5 and M1 are almost parallel at the tip. So I suspect it might be a different species.
The tribe Seiopterini includes in Europe Seioptera vibrans, Pseudoseioptera demonstrans and some species of the genus Homalocephala (Fauna Europaea). Together with Seioptera vibrans Homalocephala albitarsis, H. biumbrata and H. mamaevi are recorded in Germany.
In the key of UK species is mentioned that larvae of Homalocephala biumbrata develop under the bark of fallen aspen.
The 2 UK species differ in the color of legs (H. albitarsis: completely reddish and H. biumbrata: dark-brown to black) and in the restriction of brown coloration to cell Sc (H. albitarsis) or further extension to r-m (H. biumbrata).
Could the flies shown here belong to the genus Homalocephala, perhaps H. biumbrata?
If so, the yellow halteres would speek for biumbrata and exclude H. mamaevi with dark brown halteres.(Homalocephala key of E. P. Kameneva & V. A. Korneyev)
But H. biumbrata I could neither find in the Catalogue of Life nor in Systema Dipterorum. A search for the basiomym Psairoptera biumbrata Wahlberg, 1839 in Systema Dipterorum resulted in the valid name Homalocephala albitarsis Zetterstedt.
Now I am puzzled.