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#1 2018-03-11 19:09:33

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1019

Phaonia errans, maybe?

It's a while since I tried to ID a fly. This one, against a dull and complex background, makes it really difficult - weathered wood fencing. The results are not great!
However ... The leg bristles are difficult to discern, which is a bad start. But what I can see otherwise is consistent with Phaonia errans (I think) , and it is a credible candidate if one uses the Fonseca key, and make a few assumptions.

The last image (truly awful) is the only underside/sideways view, but at least it shows that the front femora are mainly dark (though with paler apices), and the mid and hind femora, and tibia, all orange.

Acceptable ID?  Seen March 8th.

Nigel G.


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#2 2018-03-13 15:48:42

AliCullaloe
DF Members
Name: Ali Shuttleworth
From: Fife, VC85
Registered: 2014-08-20
Posts: 81
Website

Re: Phaonia errans, maybe?

One pair of pre-scutellar bristles rather than two says to me "not errans", though I don't have a suggestion for the moment.

Cheers
Ali

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#3 2018-03-13 16:15:32

LisHarris15
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Name: Array Array
Registered: 2017-10-24
Posts: 25

Re: Phaonia errans, maybe?

Need to check pd seta on tibia 3

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#4 2018-03-13 16:49:23

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1019

Re: Phaonia errans, maybe?

I don't have a view of the hind tibia, though not for want of trying.

I did notice the fact that it only has one pair of pre-scutellar bristles, but then I didn't see any reference to those bristles in the part of the key leading up to "errans".

I think this is just another of those "tease" examples, where the conditions for images were far from ideal, and I missed the momentary opportunity to get some side views because I had just glanced at my camera settings, and not kept an eye on the fly as it did a pirouette!

Nigel G.

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#5 2018-03-13 17:54:06

AliCullaloe
DF Members
Name: Ali Shuttleworth
From: Fife, VC85
Registered: 2014-08-20
Posts: 81
Website

Re: Phaonia errans, maybe?

Yeah, it's not mentioned in the key, but its the first thing I check if I think it's errans. I'll have 50p each way on P.valida

Ali

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#6 2018-03-13 19:38:04

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1019

Re: Phaonia errans, maybe?

Thanks for your help and suggestion, Ali.
I am not now going to bet on P. errans, but P. valida (= viarum in the old key), having looked at the differences in the key.

Here is one of several shots I deliberately over-exposed to try to get some better judgement of the parts in shadow.
The bases of the antennae are indeed reddish-yellow. This one shot shows it better, but several with better lighting do confirm that feature. So it can't be errans, which has entirely black antennae.

Additionally, whilst my awful shot of the underside suggests darker front femora, the new image shows at least the visible outer halves of the front femora are orange. Maybe just the bases are darker.

It does indeed look like it could be P.valida.

Nigel G.


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Last edited by Gateside (2018-03-13 20:30:21)

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#7 2018-03-20 13:03:51

AliCullaloe
DF Members
Name: Ali Shuttleworth
From: Fife, VC85
Registered: 2014-08-20
Posts: 81
Website

Re: Phaonia errans, maybe?

Hi again

After keying through a specimen last night and considering this is probably a recent photo (?) I'm going with P.tuguriorum (signata as was). Another feature which rules out errans is the existence of posterior seta on the fore tibia. But valida is supposed to have a conspicuous forward bend on vein M, which this doesn't appear to have. Also it appears to be an autumn fly where tuguriorum is spring-autumn. P.tuguriorum also has yellow antennal pedicel and partly darkened front femora so those features are also good.

Cheers
Ali

Last edited by AliCullaloe (2018-03-20 13:13:45)

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#8 2018-03-20 14:30:04

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1019

Re: Phaonia errans, maybe?

Hi Ali

Thanks for those extra thoughts. I had actually shoved this to one side as not likely to get a definite ID, and will now have another look.

I'd given up on it being P.valida anyway (not happy about the solitary pair of pre-scutellar bristles just for starters), and discounted errans too. P. tuguriorum looks a good possibility, and I have 2 sets of decent photos from previous examples to compare and contrast. Unlike this set ... which I am happy to label as abysmal.  It's not worth submitting images like this in the future.

Nigel

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#9 2018-03-20 15:06:38

AliCullaloe
DF Members
Name: Ali Shuttleworth
From: Fife, VC85
Registered: 2014-08-20
Posts: 81
Website

Re: Phaonia errans, maybe?

"It's not worth submitting images like this in the future."

Not sure about that. Always worth pushing the boundaries. When I come across this cluster of species it'll definitely help to have chewed over the features available for determination. Have a quick look around at P.valida pics. The bend on vein M is really obvious even from a quite oblique angle and it's clearly visible from your pics that it isn't valida. If these features get visited enough times then separating them will become second nature (?!).

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#10 2018-03-20 22:15:56

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1019

Re: Phaonia errans, maybe?

In an ideal world, I might aspire to this:
"If these features get visited enough times then separating them will become second nature (?!)."

The trouble is I'm very much a generalist, and so I get to be familiar with things for a bit, then get diverted into something else ... like plant galls for instance. There's no hope for me!
roll

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