Thread subject: Diptera.info :: Elgiva cucularia? --> Dichetophora sp. (cf. finlandica?)

Posted by ukursawe on 10-10-2021 11:42
#1

Hi,

Few days ago I took a few pictures of a longish, medium-sized fly on a leaf of one of our garden shrubs.

The appendices on the antennae seems to suggest it might belong to the family Sciomyzidae. My best guess would be Elgiva cucularia. Is it possible to confirm or reject that speculation based on the picture below?

Germany, Garden in Southern Bavaria, Munich (-West), 25.09.2021, app. 6-8 mm

Greetings, Uli

Edited by ukursawe on 10-10-2021 14:27

Posted by ukursawe on 10-10-2021 12:00
#2

Second image

Posted by Nikita Vikhrev on 10-10-2021 14:15
#3

No, Dichetophora (finlandica?)

Posted by ukursawe on 10-10-2021 14:26
#4

Hi Nikita,

thanks for the correction. I didn't know that species, but it is obviously a better match, especially with respect to the regular pattern on the outside (front) edge of the wings.

Thanks & greetings, Uli

Posted by ukursawe on 10-10-2021 16:54
#5

Hi,

from what I gathered in the Web, the number of "postalar bristles" seems to be a criterium to distinguish D. finlandica (1 pt bristle) from D. obliterata (2 pt bristles).
I tried to extract a few views from that region from my images, but, since I don't have any experience, I can't make a clear diagnosis from these rather grainy and blurry images (sorry for that).
Is it possible to make the distinction here?

Greetings, Uli

PS: In the posterior view I have marked the region, where I think these postalar bristles could be located. I count two there :)

Edited by ukursawe on 10-10-2021 16:57

Posted by Nikita Vikhrev on 11-10-2021 13:01
#6

Uli, I could not and still can not say 2 or 1 postalar bristle.
There are other characters: in D. finlandica:
1. Thoracic patternmore greish
2. Antenna longer

Posted by ukursawe on 11-10-2021 14:15
#7

Hi Nikita,

thank you for your explanations. The thorax was rather light gray and not light brown, but colors in an image depend on a lot of factors (monitor calibration, white balance etc.), so it is probably not 100% reliable.
Anyway, I am quite happy with the genus and an optimistic "cf. finlandica", maybe.

Thanks & Greetings, Uli

Posted by eklans on 11-10-2021 15:22
#8

Hi Uli and Nikita, I'm not 100% sure, but my first D. obliterata was from 2016 and I noted: "femora whitish yellow, tip orange" while finlandica the femora are completely orange.
Here's a couple obliterata from this afternoon 2021-10-11 on my housewall:

Posted by ukursawe on 11-10-2021 15:55
#9

Hi Eric,

I remember I read something similar in the german Wikipedia-Entry for D. obliterata:

https://de.wikipe...obliterata

Unfortunately, only the german version mentions that "the apical sections of the femora are noticeably red, which distinguishes the species from the very similar species D. finlandica".
I hope my translation is correct, but of course, generally, the reliability of Wikipedia entries can be questionable.

This publication here mentions at least three criteria to distinguish the two species:

Sciomyzidae Fallén, 1820 (Diptera) collected in the Mercantour National Park, France
Jean-Claude Vala, Christopher D. Williams 2015

Citation:
"The species (Dichetophora finlandica) has been often confused with the second Palaearctic species mentioned below. However, it differs by the presence of only one pair of post-alar setae, the third antennal segment elongated and very acute, and the yellow femur III."

I am in no position to judge if these claims are valid or not, even though I am still wondering, why I found that specimen in a garden at the perimeter of a huge city like Munich. No streams/ponds in the immediate vicinity, as far as I know.

Greetings, Uli

Edited by ukursawe on 11-10-2021 15:58

Posted by Nikita Vikhrev on 11-10-2021 16:42
#10

Hi Eric, I agree that colouration is variable. Also D. obliterata is mostly W-European species and I examined only few specimens.
However, the length of antenna on your image seems to me shoter than that on Uli's images.
Anyway, I do not insist that Uli's fly is finlandica.