Thread subject: Diptera.info :: Anyone for this species?

Posted by gardensafarinl on 22-01-2006 19:51
#1

In my archive I found these two pictures of a species I haven't been able to identify. Some details are visible, many are not, but maybe someone knows. I would be grateful and I settle for genus or family as well.

Cheers,

Hans

www.gardensafari.net/temp/diptera_sp_ha2_3223.jpg

www.gardensafari.net/temp/diptera_sp_ha2_3225.jpg

Posted by Kahis on 22-01-2006 23:43
#2

Siphona (Tachinidae)?? This genus is normally very easy to identify by the long and folded proboscis, but in this case the mouthpart are in use and so extended that I'm not sure about anything. The head and antenna shape isn't the most typical for Siphona so this may be one of the other small, grey tachinids.

Edited by Kahis on 22-01-2006 23:43

Posted by gardensafarinl on 23-01-2006 06:55
#3

Dear Kahis,

You could be right indeed. It does look very much like the one in the picture below (Siphona geniculata), which is located at BioImages. Even the hairs on the abdomen seem te be corresponding. Funny thing is that the beak is in the same position as in my picture.
There are quite a number of species in this genus. Could I be safe calling mine a Siphona, or are there yet other similar groups?

Thanks a lot,

Hans

www.bioimages.org.uk/MMWSt/NikonD100+T90/2005/05-08/05-08-06/05H06A_1.jpg

Posted by Zeegers on 23-01-2006 21:58
#4

Hi guys,

Those are Siphona indeed. As easy they are to identify to genus level, as difficult it is to identify them to species level. Siphona is notorious for that. Really one cannot make certain ID's from pictures.
The good news: the 2 above are indeed S. geniculata
the bad news: the third one is definitely NOT.

My guess would be: Siphona cristata.
But don't kill me if I'm wrong !


Theo Zeegers

Posted by gardensafarinl on 23-01-2006 23:21
#5

Dear Theo (and the others, of course),

Thanks for id-ing the flies. I am very happy to know what they are. Leaves us with the problem of the 3rd one as seen in BioImages. For non-experts like me this site has a feel and look of authority about it. On the site is the following information about the species considered to be S. geniculata:


BioImages: The Virtual Field-Guide (UK)
Siphona geniculata (DeGeer, 1776) (a parasitic fly)

Date: 6 August 2005, VC: Berks, UK, Ref: 06/08/2005[A]
Female imago

Record Summary: visiting Marsh Ragwort

Identification Notes: 4 post-sutural DC, T1+2 with pair of median marginals

Although Belshaw's key only works for males, S. geniculata is by far the commonest species (CMTR, pers comm).


At this address: http://www.bioimages.org.uk/HTML/R159651.HTM

As I am no expert in this field at all, I leave it to your discretion to get in touch with them or not. Either way suits me. I think they had some doubts themselves considering the last remark. Still I think that a site which is considered to be an authority can not base themselves on whether an animal is commonest or not....
Oh, hell, why are flies so darned difficult indeed?!

Cheers,

Hans

Posted by Kahis on 24-01-2006 21:39
#6

Gardensafari wrote:
Oh, hell, why are flies so darned difficult indeed?! Cheers, Hans


They are?:o That's news to me:D

I'd say flies are easier than for example micro-moths! I challenge you to identify Coleophora species or fritillaries from photographs of upper wing surface:p

The ID problems are simply caused by the unpopularity of this group among entomologists (especially amateurs) and the large number of species. Once you have the literature many flies are quite easy to identify.

Posted by Zeegers on 24-01-2006 21:56
#7

Right, Kahis,
but be warned: Siphona are not easy, even if you try hard.
Nevertheless, some things can be sure even in Siphona, and the third picture is not S. geniculata.
As said, if I was forced to shout a name mine would be cristata.
it's a male, by the way (though easily mistaken), so the disclaimer on Belshaw's key is not relevant either.

Then there is some confusion on the names, thanks to Anderson.
Anderson proposed to call cristata auct. geniculata and geniculata auct. urbana. This proposal has been suppressed. The old names, used for more than 100 years, are fixed.

So maybe the third picture was identified as geniculata sensu Anderson, in which case we do agree, since

geniculata sensu Anderson = cristata

Anyway, the first two pictures are from a different species than the third.

I don't kill the messenger, personally I'm against needless changing well established names exactly because of this type of confusion.


Theo Zeegers

Posted by Kahis on 24-01-2006 22:45
#8

Theo, I know and that's why I sent my Siphona to Bergstr?m (who took them to Anderson) for identification. Good thing too since there was an apparently undescribed species among them. Unfortunately only one male, fortunately the collecting site isn't that far from where I live and I can try to collect some more specimens this spring.

Edited by Kahis on 24-01-2006 22:46

Posted by Zeegers on 26-01-2006 23:16
#9

Hi Kahis,


Looking forward to again a new species from FennoScandia.
However, I should warn you that even Anderson (whom I consider to be a much bigger expert in Siphonini than myself) made some mistakes in the past by jumping to conclusions (martinii for instance).

So do collect more (males !) and let's see if the spec. nov. sticks.

You will have to wait a little while, I guess,

your waxwings are still in our gardens in Holland


theo

Posted by ChrisR on 31-01-2006 15:24
#10

Hi folks - i will pass on your comments to Malcolm Storey, who maintains BioImages. I have proferred a few identifications in the past, based on the specimen (not the photo), but in this case it looks like it was ambiguous. However, I note Belshaw's key comments that (in the UK) median marginal bristles on T1+2 are unique to geniculata and setosa, though Theo might have an opinion on whether that is in fact the case :)

Best wishes, Chris R.

Posted by gardensafarinl on 31-01-2006 18:42
#11

Dear Chris,

Thanks for passing this on to Malcolm, who I don't know personally. I do admire his site though and the site is considered to be an authority by most amateur biologists. But sometimes even authorities can be wrong, of course. And even the best of keys often are not completely flawless. So give him my regards and tell him to keep up the good work.
I do have one request though. I have the fly on my site as Phiona geniculata at the moment. Should Malcolm or any of his experts still disagree with Theo, please let me know, for in that case I will probably put my fly on the site as just a Phiona species. After consulting Theo, of course.....

Regards,

Hans

Posted by Zeegers on 31-01-2006 22:07
#12

The presence of marginals on T 1&2, both central and lateral, is indeed an important feature in Siphona. However, the central pair is unstable in S. cristata: it can be from completely absent up to completely developed.
The picture is not taken dead lateral, but it looks like the parafacialia are narrow and bare no hairs. Moreover, the vertex is quite golden yellow. All this clearly suggests S. cristata.
As I have explained before, this equals S. geniculata sensu Anderson
(now suppressed).
But to me the ID is not sure, just likely.0


Theo

Posted by ChrisR on 14-02-2006 20:59
#13

I passed the info on to Malcolm of BioImages and this is his reply:

"Thanks for sorting out my Siphona geniculata/cristata. I've changed it
in the database; the website will be updated next time it's rebuilt.
(Probably late March)

Apart from adding lots more pictures, the site has changed little since
it began nearly ten years ago. Am currently in the middle of a major
revamp which will add literature and predator/prey parasite/host
relationships. I'd like to include Theo's comments in the notes on
Belshaw's key if that's OK.

Thanks again for your comments.

Malcolm Storey
www.bioimages.org.uk"

Posted by gardensafarinl on 15-02-2006 18:14
#14

That's great indeed. I suppose we are all happy now. If only all people of the world would show this kind of attitude... The world would be a better place to get bitten by a mosquito in!

Cheers,

Hans

Posted by Zeegers on 15-02-2006 20:04
#15

Dear Malcolm


If I say something in public, you are welcome to quote me.
Just be sure to get the message across:
in most cases Siphona cannot be identified from pictures.
The matter on nomenclature has been published by O'Hara and others.
You can find a reference in Tachinid Times (see links)


Theo