Diptera.info

Posted by conopid on 05-10-2007 20:33

One for Nikita and Igor?

I cannot decide which UK Sciapus this is. I think it might be Sciapus longulus. None of the tarsi appear to be modified, all tarsi are dark, and it has a fairly metallic face.

All help appreciated.

Posted by conopid on 05-10-2007 23:18

Thanks Kahis,
My key to British Dolichopidiae says that zonatulus fly has long yellow hairs on the ventral side of the front femora, but the hairs on this fly appear to be quite short and dark. Is this a problem for S. zonatulus?

Posted by Kahis on 06-10-2007 00:23

Hmm. Meuffels & Grootaert (1990) says for S. zonatulus "Femur I without bristles or setae, bearing only very short white hairs; posteriorly near tip a few black bristlelike setae".

How old is your key? The names in this difficult group have been shuffled a few times before 1990. S. contristans sensu d'Assus-Fonseca 1978 is the real S. contristans which is not synonymous with S. zonatulus.

The male of S. longulus has long, strong bristles on the fore femur (length >2x width of the femur). More likely is S. basilicus, which is very close to S. zonatulus. The two species differ in the position of the small setae of fore basitarsus (barely visible in the pictures), details or male genitalia, and size. The last two characters can not be judges from your photos.

Cheers,
Jere K.

Posted by conopid on 06-10-2007 10:34

Hi Jere,
I have Fonseca's 1978 British Doli key. So presumably it lists the true contristans, although the latest UK check list has zonatulus as synonymous with contristans - confusing!

My specimen has no pale hairs on the ventral side of Femur 1, just the short dark hairs in the photo. I think I'll try running it through the key again to see if I have made an elementary mistake somewhere. ;)

Cheers
Nigel

Posted by Igor Grichanov on 06-10-2007 13:49

#10

Sciapus zonatulus (Zetterstedt,1843) [Psilopus] (Bezzi,1903: Katal. palarkt.Dipt. 2: 292) *
=Psilopus zonatulus Zetterstedt, 1843: Dipt.Scand. 2: 628 // probable syn. of Sciapus contristans (Wiedemann, 1817) (Lundbeck, 1912: Dipt.danica 4: 36); rest. Meuffels & Grootaert, 1990: Bull.Inst. r.Sci.nat.Belg., Entomol., 60: 164 ** Palaearctic: Belgium, England, Finland, Germany, Poland, Spain, Sweden, Switzerland, Netherlands * Sciapus

Posted by conopid on 06-10-2007 14:23

#11

Jere and Igor,
Thanks for your helpful responses. Okay, I have had another look at the fly and I cannot get a match with any of the species described in Fonseca. The only possibility might be S loewi (now also listed as a synonym of contristans)! However I cannot detect any obvious modification of the mid tarsus apical segment. So a question, is the lateral flattening of the apical segment slight and not very obvious? If this is the case, then I think my fly is likely to be Fonseca's S loewi. (now S contristans)

The fly certainly has extensive white dusting over the frons, thorax and abdomen. Does S contristans have such dusting?

Another feature of my fly, is that the face is actually glistening bright white, rather than metallic. I moved the light around to see this effect, which I had previously not noted.

I need a good reference collection! :D

Sorry I am getting very confused. But I now think this fly is S contristans (named as S loewi in Fonseca 1978) :@

Any comments?

Edited by conopid on 06-10-2007 14:33

Posted by David Gibbs on 06-10-2007 15:07

#12

Nigel, forget Fonseca for the constrians group of Sciapus, you need to get a copy of Meuffels & Grootaert (1990). i would have thought your specimen would run to maritimus in Fonseca's key, which includes maritimus, zonatulus and basilicus.

although the latest UK check list has zonatulus as synonymous with contristans - confusing!

no, constrians is listed as : authors misident meaning that someone, in GB literature, used the name constrians for what later proved to be zonatulus.

you specimens looks identical to my specimens of zonatulus but always as well to check genitalia.

Posted by Kahis on 06-10-2007 15:18

#13

Here's the full reference:
Meuffels, H. J. G. & Grootaert, P. 1990. The idenitity of Sciapus contristans (Wiedemann, 1817) (Diptera: Dolichopodidae), and a revision of the species group of its relatives. Bull. Inst R. Sci. Nat. Belg., Ent., 60: 161-178.

Posted by Kahis on 06-10-2007 15:22

#15

conopid wrote:
Thanks for your helpful responses. Okay, I have had another look at the fly and I cannot get a match with any of the species described in Fonseca.

This is exactly what should happen, as your specimen represents a species missing from Fonseca's key! It runs to couplet 7 and then fails to match either choice - as it should.