Diptera.info :: Identification queries :: Diptera (adults)
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 Tachinidae
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| neprisikiski |
Posted on 12-03-2011 01:46
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Hello, please hellp me in identification of the following specimen. Unfortunately, fly not in a good condition. It is male, collected in the begining of June. Thank you in advance.
neprisikiski attached the following image:  [112.95Kb] Edited by neprisikiski on 12-03-2011 02:23 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:47
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Parafacial with setulae, outlined; eyes with setulae, but mostly damaged
neprisikiski attached the following image:  [100.07Kb] Edited by neprisikiski on 12-03-2011 02:17 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:48
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Wing
neprisikiski attached the following image:  [119.41Kb] Edited by neprisikiski on 12-03-2011 02:07 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:48
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Posterior part of the head with white hairs; prosternum hairy
neprisikiski attached the following image:  [82.87Kb] Edited by neprisikiski on 12-03-2011 02:19 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:49
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Katepisternum with three setae and barette bare
neprisikiski attached the following image:  [110.05Kb] Edited by neprisikiski on 12-03-2011 02:10 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:49
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Four anterodorsal setae on middle leg
neprisikiski attached the following image:  [112.23Kb] Edited by neprisikiski on 12-03-2011 02:14 Erikas |
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| neprisikiski |
Posted on 12-03-2011 01:56
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Syntergite 1+2 hollowed to about the middle
neprisikiski attached the following image:  [145.37Kb] Edited by neprisikiski on 12-03-2011 02:13 Erikas |
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| Zeegers |
Posted on 12-03-2011 11:00
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Member Location: Soest, NL Posts: 7342 Joined: 21.07.04 |
Hwoah, this is going to be though. The arista is bare, is that correct ? Theo |
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| neprisikiski |
Posted on 12-03-2011 16:34
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
I cannot see any hairs on arista; coxa is bare on posterodorsal surface as well. Note that the specimen is not in an optimal condition and something could be misleading.
Erikas |
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| Zeegers |
Posted on 13-03-2011 10:29
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Member Location: Soest, NL Posts: 7342 Joined: 21.07.04 |
so, that was not easy at all. I think it is Ptesiomyia alacris Congratulations Theo |
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| neprisikiski |
Posted on 13-03-2011 18:44
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Dear Theo, I have Ptesiomyia alacris in my collection for a comparison, and it was my original identiication. The latter species have parafacial bare, and this is the main reason why I am looking for a truth. Is it possible, that hairy parafacial is not a stable character? Erikas |
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| Zeegers |
Posted on 13-03-2011 19:10
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Member Location: Soest, NL Posts: 7342 Joined: 21.07.04 |
I noted those hairs on the parafacial as well, though they are difficult to assess. The combination of restricted excavation on syntergite 1, hairy prosternum, 4 post DC and distinct apical scutellar bristles is very unusual indeed. Database by Tschornsig gives only Ptesiomyia. The general head shape is OK as well. I have 1 in my collection, I will check. Theo |
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| neprisikiski |
Posted on 13-03-2011 19:18
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
This specimen was collected in the same locality with other specimens, which I identified as Ptesiomyia alacris, but with clearly bare parafacial! So the locality is the same, but those hairs are obvious, though poorly visible on the photo...
Erikas |
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| Zeegers |
Posted on 13-03-2011 22:16
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Member Location: Soest, NL Posts: 7342 Joined: 21.07.04 |
Mesnil (in Lindner) very clearly states that the parafacial is hairy on 'upper half' in Ptesiomyia alacris, and even more in other species of this genus. This is little more than half, but given all the evidence I still think it is Ptesiomyia alacris. The main question should be: what are these 'Ptesiomyia' with bare parafacials ? Those are the aberrant ones. Theo |
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| neprisikiski |
Posted on 13-03-2011 22:42
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Well, please look to the specimen in a good condition, it has only a few setulae below the lowest frontal bristle.
neprisikiski attached the following image:  [95.15Kb] Erikas |
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| Zeegers |
Posted on 14-03-2011 08:53
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Member Location: Soest, NL Posts: 7342 Joined: 21.07.04 |
Thanks The difference is not that large that is worries me. Moreover, the first one is male (?) and the second one female, could be slightly sexual dimorph ? Maybe someone should compare southern Ptesiomyia with northern, to check that those are really the same species. Wouldn't be the first time that there are actually 2 species. That's all I can say, for the moment Theo |
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| ChrisR |
Posted on 14-03-2011 10:16
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 Super Administrator Location: Reading, England Posts: 6972 Joined: 12.07.04 |
Very interesting find - I've never come across Ptesiomyia 
Manager of the UK Species Inventory in the Angela Marmont Centre for UK Biodiversity at the Natural History Museum, London, Coordinator for the UK Tachinid Recording Scheme, my Diptera blog |
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| neprisikiski |
Posted on 14-03-2011 17:33
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Member Location: Lithuania Posts: 811 Joined: 23.02.09 |
Probably it cannot be nothing else than Ptesiomyia alacris (the same locality), I think that hairy parafacial is not a stable character and need correction in the key. Thank you for your discussion, Theo and Chris.
Erikas |
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