Diptera.info :: Identification queries :: Diptera (adults)
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 New Lindneromyia for the Netherlands? (Platypezidae)
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| weia |
Posted on 09-10-2012 11:31
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Member Location: Posts: 390 Joined: 11.07.11 |
Last week I was able to take two pictures of a small fly (3.6 mm) running fastly on a leaf in the garden, Utrecht, Netherlands. The venation was typical and after a long search through pictures (I don't have literature, dragonflies are my thing) I came to the Platypezidae and genus Lindneromyia. Because only one of that genus is known from the Netherlands it should be L. dorsalis. But a Dutch dipterist questioned my identification and indeed it seems to be L.hungarica. Unfortunately I have only these two pictures, no head from the front for example. A difference exists in the width of the frons between the eyes, I can only show the upper part of the head and indeed this seems quite narrow. So please dipterists, have a close look so we can confirm hungaica or not.
weia attached the following image:  [149.13Kb] |
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| weia |
Posted on 09-10-2012 11:32
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Member Location: Posts: 390 Joined: 11.07.11 |
Second picture:
weia attached the following image:  [186.17Kb] |
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| Paul Beuk |
Posted on 09-10-2012 12:33
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 Super Administrator Location: Netherlands Posts: 19268 Joined: 11.05.04 |
You might be right but I am not familiar with the species. Let's wait for michal tkoc (if it lasts too long, send him an PM  ).
Paul - - - - Paul Beuk on https://diptera.info |
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| weia |
Posted on 09-10-2012 16:06
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Member Location: Posts: 390 Joined: 11.07.11 |
I have contacted him and he said that it looks good, coloration for example. But certainty is something else. I hope the width of the head between the eyes contains a clue. |
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| Paul Beuk |
Posted on 09-10-2012 17:13
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Super Administrator Location: Netherlands Posts: 19268 Joined: 11.05.04 |
Yes, well, go out and collect a few and send them over... We should have a couple of nice days still ahead of us.
Paul - - - - Paul Beuk on https://diptera.info |
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| weia |
Posted on 13-10-2012 17:29
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Member Location: Posts: 390 Joined: 11.07.11 |
Chandler 2001 contains a drawing of the head and here the only structural difference for females hungarica/dorsalis can be found. I obtained the drawing and text of Chandler via a Dutch dipterist. The text says '[hungarica] "Frons narrower than an eye, at most 0.3 head width"; [dorsalis] "Frons nearly equal to maximum eye width".' The drawings suggest the difference also results in a difference on top of the head. More about this in a moment. By the way: I never saw the fly again although more than thirty mushrooms of the right genus are peresent (Agaricus). weia attached the following image:  [102.19Kb] |
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| weia |
Posted on 13-10-2012 17:50
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Member Location: Posts: 390 Joined: 11.07.11 |
I have no picture from the frons, often those are difficult to make in real life. More likely a picture from above can be made. Is the difference than still visible? I collected pictures of hungarica and dorsalis from the web and put them in two folders according to the coloration of the body: clearly striped versus hardly striped. Most happily the coloration of the bodies correlated completely: much grey / less grey. Also the gap between the eyes correlated: narrow grey gap between the red yes versus quite broad gap. So the folders were ungarica and dorsalis. None of the pictures (very very few of hungarica unfortunately) showed the frons, none is giving a perfect perpendicular look on the head. I took two ones close to perpendicular, drew a line touching the front ocell and measured the width of the gap and the width of the eyes. Due to perspectivical distortion both eyes give different measurements, the mean of them is a better measure (but still affected by distortion). Now for hungarica the gap is about 0.75 of eye width, or in words: the gap at the height of the ocell is clearly narrower than eye width. (I forgot whose pictures I've used.) weia attached the following image:  [74.85Kb] Edited by weia on 13-10-2012 17:50 |
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| weia |
Posted on 13-10-2012 17:57
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Member Location: Posts: 390 Joined: 11.07.11 |
For dorsalis the measurement gives: gap width 1.14 of mean eye width. Or in words: gap at the height of the ocell a bit wider than eye width. Note by the way that the eye has no fluent contour, it is a bit pointed (lower picture). It seems most dorsalis females have this and hungarica hardly so. Now look at my upper picture, closer to 0.75 or to 1.14? The gap is clearly much narrower than eye width, notwithstanding all perspectivical distortion. weia attached the following image:  [112.19Kb] Edited by weia on 13-10-2012 17:59 |
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| michal tkoc |
Posted on 21-11-2012 18:45
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 Member Location: Prague, Czech Republic Posts: 237 Joined: 07.11.06 |
The first two pictures are for sure L. hungarica, but I am afraid, that you cannot publish, since you do not have any voucher specimens. If you want to know, why is this L. hungarica just tell me please.
Curator of Diptera, Entomology Department, National Museum Prague. PhD. Student, Charles University. Prague, Czech Republic. |
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