Diptera.info

Posted by Stephen R on 24-01-2010 19:03

I posted these photos in October, when I found this moribund Coenosia, but later deleted the post after there were no takers. Now I am the proud possessor of an antique Nikon stereo microscope from Ebay and a copy of Muscidae of Central Europe, so I thought I'd have a go at my only specimen. Unfortunately the key led me to a species (C. emiliae) we don't have in Britain. Is it probable that this fly is one the book doesn't cover, or have I gone horribly wrong somewhere?

The characters are checked were:
No approximated av +ad on t3
no dilated 5th tarsomere
no approximated d+pd on t3
long lower squama
female
no spine-like tip to flagellomere
proepisternum with 2 setae
pd on t3
no ad on t1
femora not entirely yellow

Shall I give up and wait for something easier to fly along?

Edited by Stephen R on 16-07-2010 17:07

Posted by Stephen R on 25-01-2010 22:50

Hi Joke,
The size is 4.5mm. I think my mistake was to say there was a pd on T3 - I think the one I was looking at was truly dorsal. Assuming that, I get through eventually to C. albicornis, provided that you count the white line down the frons as part of the frontal triangle. Here are pictures of the hind tibiae and the thorax. What do you think?

Posted by javanerkelens on 26-01-2010 00:35

#10

When i check everythink with what i can see, ....i also come to C.emiliae Lukasheva 1986 (only found yet in Germany, Czech Republic and Slovakia)
Fore femur infuscated, dorso-apical markings on hindtibia (can see clear the dorsal side of midfemur)
t2 with ad and t3 with 1av+1ad+1pd
The only mistake maybe made , can be the hairs on proepisternum.....then it would be an C.rufipalpis..? (female not always have beginning of abdomen yellow)

And C. albicornis has no pd on t3!
Maybe Nikita or Stephane could say more ....

Joke :)

Posted by javanerkelens on 26-01-2010 16:30

#12

In the beginning i had the most problems, how to place the leg in the right position.
I made from the anterior dorsal a posterior dorsal and from the posterior dorsal a posterior ventral..etc.:o
The hindtibia has for 90 % only av+ad+pd+pv setae and mostly no anterior and posterior seta
(sometimes the pv setae are more in a posterior position, but mostly these setae gives not the most problems)

I think on your species the seta is a pd seta and no posterior seta..

I made a drawing of the setae (maybe helpful) and a example on a fly

Joke :)

Edited by javanerkelens on 26-01-2010 19:59

Posted by jorgemotalmeida on 26-01-2010 17:54

#14

suggestions: the first sketch at the left put below: LATERAL VIEW of the leg.
The middle: SEEN AS ABOVE, as we cut the leg transversally, being the ventral.. the underside of the leg. (exempli gratia, ventral seta/bristle: the insertion of the ventral bristle is located in the underside of the leg (considering the frontal view of the last photo) . So we almost (see below the text) cannot see in this last photo the insertion of ventral setae with the most proximal legs (foreground) to us, the distal ones sometimes show them but not easy to see! However, we can see the point of insertion of ventral bristles IF the leg is twisted like it happens in the hind tibia where we can see av with its insertion point - I'm considering the fly as always being transverse with us.)
The right sketch (above all of them) I would suggest to put below the legend SEEN AS ABOVE , but this time, as we had our fly with the biggest length transversally to us. This view is perfectly showed in the last photo.
(caution: the hind tibia is gently twisted in this view. That's why we see many ad)

Edited by jorgemotalmeida on 26-01-2010 18:15

Posted by Stephen R on 26-01-2010 19:52

#15

Joke and Jorge, many thanks for your illustrations and explanations, which are very clear. From what you say there should be a 90 degree difference between an av and a pd, and this looks right for the fly in your picture - there are no bristles on the line going down from the very tip of the knee; but in my fly the bristle seems only 45 degrees round from the ad bristles. Does this not make it dorsal?

Posted by javanerkelens on 26-01-2010 20:06

#16

Always very difficult to explane, because the legs are never clear in dorsal, anterior, etc. view (on photos)
Maybe everyone is already tired of all the drawings :o , but a last one to give it a try.....

From what you say there should be a 90 degree difference between an av and a pd

Not always, because you can see there is a relative wide area where a pd or ad can be in the posteriordorsal and anterior dorsal area.
So if the ad almost is standing near the "dorsal line" and the pd is also more near the "dorsal line"....the differents can be less 90 degree !

Joke
(Jorge, i made some changes in my first drawing..;))

Edited by javanerkelens on 26-01-2010 20:23

Posted by javanerkelens on 27-01-2010 00:43

#18

Maybe a little exaggerated (mostly the setae is standing nicely in a ad and pd position)
But sometimes they have a little differents.
I just mean to say, it is not always precise 90 degree.
There is some variation to it.
When i look at the chaetotaxy from 5 the same species, the chaetotaxy can be a bit different each species. But mostly the numbers of hairs are the same (for instance 1av+2ad+1pd+7pv)
Sometimes the av is close to the ad and sometimes they are far apart and you almost think the av it is a pv....:D
Nice hobby we have....:o:D:D:D

Joke

Edited by javanerkelens on 27-01-2010 00:46

Posted by Stephen R on 27-01-2010 13:21

#21

Thanks for the reassurance, Oxycera - I thought my pig-headedness must be irritating everone :o Now I can see myself as the grain of sand in the oyster stimulating the production of pearls of great price B)

Joke, Figure 44b in M of CE is of the hind tibia of C. flavicornis. It looks similar to this one, and the seta in question, which must be the one the key refers to as a posterodorsal, is labelled 'dorsal' in the diagram. This illustrates that a seta may be morphogenically posterodorsal but appear in a more or less dorsal position. Have I got the point?

We seem to have proved that this fly is either an anomalous individual or from a species not covered in the key (apart from being far outside its known range, emiliae doesn't seem to have f1 grey). I'll try to catch some more when they re-appear - I think I saw quite a few of these last summer. It's a pity it wasn't albicornis, because the description of the frontal triangle fits exactly, as does everything else in the description in my book, except that the fore-femur should be dark dorsally and yellow ventrally whereas this one looks grey all over. Oh, and it has a pd on t3 :D

Very many thanks, Joke. You can have your life back now :)

Stephen.

Edited by Stephen R on 27-01-2010 13:24

Posted by Stephen R on 02-02-2010 20:53

#22

I'm very sorry for re-opening this thread, but this Coenosia is keeping me awake at night :o - and it's not even Halloween.

My question is (still): is it at all possible that the authors of MCE have interpreted the bristle in question as a dorsal pre-apical and not as a (sub-median) posterodorsal? My reasons for thinking that this may be so are:

1: the diagrams (44c,d) illustrating the species (means, tigrina) with 'approximated pre-apical dorsal and posterodorsal setae' show these at a distance from the tibial apex which is similar to the position of this one - so this could be interpreted as 'pre-apical'. Also it looks like the last in a series with the other pre-apical bristles.

2: Although the bristle points in a somewhat posterodorsal direction, its origin is on a row of setulae which go straight to the point of the knee: almost exactly on the dorsal line.

3: The couplet (75) which separates trilineella, flavicornis and emiliae, which have the posterodorsal, from the rest, including albicornis and lineatipes, which do not, calls for '1 or more submedian posterodorsal setae', and the diagram for C. emiliae (44e) shows the pd higher up the tibia, almost level with the ad.

4: If you accept the above, the fly could be either C. albicornis or (perhaps more likely?) C. lineatipes; if the seta has to be a sub-median pd, there is nothing in the key that it could reasonably be.

I add some photos of a living fly (5mm) from earlier in the summer which I believe is of the same species:

Edited by Stephen R on 02-02-2010 21:05

Posted by javanerkelens on 02-02-2010 22:09

#25

Just lets go again though the key (and forget for now all the setae :S)

1 Costa extending ot apex of M1 = correct (go to 2)
2 Hind tibia without approximated av and ad setae in middle = correct (go to 10)
10 Last tarsomere not dilated on any pair of legs = correct (go to 14)
14 Hind tibia whit preapical dorsal + pd close together = wrong(they have to be very close and on the same level, and we see on photo 3 they are not !)
So....Hind tibia without strong and long closely approximated preapical dorsal+pd seta = correct (go to 17)
17 Lower squama usually much longer than upper one = correct (go to 27)
27 it is a female = correct (go to 67)
67 flagellomere without prominent dorsal tip = correct (go to 71)
71 Proepisternum with 2 setae (you sad..) = correct (go to 75)
75 hindtibia with 1 or more submedian pd = correct (go to 76)
76 fore tibia without distinct ad seta = correct (on photo 1 you can see an posterior seta on tibia 1) (go to 77)
77 femora partly darkened (fore femur is dark) , mid and hind femora darkened apically and flagellomere dark = correct ..........so must be C.emiliae

But i see also on tibia 2 an pd or posterior seta and in the discription is standing ..female has strong ad....and no mention about pd or posterior.

Just save it for now as a C.emiliae.
Than forget the fly for 14 days (have fun, go out, drink wine, etc..:D:D)
And after 14 days just try again and maybe you will see the fly as new and see things you don't see right now!

Joke :)

Edited by javanerkelens on 02-02-2010 22:11

Posted by Stephen R on 02-02-2010 23:28

#26

It's couplet 75 I have trouble with, because I don't think this is a submedian pd. Look at the diagram of C. emiliae, plate 44e - the seta is in the wrong place. Surely 'submedian' means 'not quite at the middle', rather than 'beyond the middle' of the tibia? And as I said above, this is more 'dorsal' than 'posterodorsal'.

From 75 I go to 78>79>80>81>84>85>87>88>89>90>C. lineatipes

Good idea about the wine though :D:D

Edited by Stephen R on 02-02-2010 23:51

Posted by javanerkelens on 03-02-2010 01:03

#27

The other option on couplet 75:
Hind tibia without pd setae!
But we have now a very large dorsal seta (you say it is a dorsal seta)
And i don't know a species with 1av+1ad+1dorsal seta on the hind tibia.
And with such large dorsal seta, there would be a mention about in the description of the species.

Coenosia is not an easy family and there is lots of confusion between the species.
Maybe you can save the fly for an expert, such as Nikita Vikhrev, and maybe he wil take a look at your fly!
I also have lots of Coenosia species waiting for a name, but need also some alcohol to begin with....:D:o

I wil take a very large cup of tea now.......and sleep well .....i hope :D

Joke

Posted by Stephen R on 03-02-2010 01:14

#28

Good morning, Joke!

javanerkelens wrote:
And i don't know a species with 1av+1ad+1dorsal seta on the hind tibia.

From fig. 44a, C. bilineella is such a fly, and the description doesn't mention the dorsal seta (I think because pre-apicals don't count. Only trouble is that bilineella has a short lower calypter.

Stephen.

Edited by Stephen R on 03-02-2010 12:07

Posted by javanerkelens on 03-02-2010 12:35

#29

Ok�then the dorsal seta has to be a preapical dorsal seta!
On the photo i added, we indeed can see also a preapical anterior dorsol seta.
Presuming both setae are preapical, there is indeed no posterodorsal present (couplet 75)

Then we can go again from there:

75 Hind tibia without posterodorsal setae = correct (go to 78)
78 Mouthedge seems not projecting beyond level of profrons (what i see) = correct (go to 79)
79 Is the av on t3 in a ventral position....or not (difficult to for me to say)
When it is = it is C.pudorosa
When not = go to 80
80 subcostal cell on wings not darkened = correct (go to 81)
81 antenna entirely black + only one presutural dorsocentral = correct (go to 84)
84 mid and hind femur entirely or predominantly yellow, at most apical half contrasting black = correct (go to 85)
85 hind tibia with only one av = correct (go to 87)
87 posteroventrals on whole length of hindfemur + body longer then 3.5 mm or posteroventrals only in basal half + body at most 3.5 mm
You said the fly was 4.5 mm, so there has to be pv on the whole length of the hindfemur ! = go to 88
88 presutural acrostichals in 2-3 well separated rows + flagellomere about 2.5 times as long as broad+ scutum with 2 distinct longitudinal stripes = seems correct (go to 89)
89 presutural acrostichals in 2 rows = correct (go to 90)
90 frontal triangle reaching anterior margin of frons = C.albicornis
frontal triangle not reaching anterior margin of frons = C.lineatipes
I personally think the frontal triangle is reaching anterior margin (the silvery line going from the triangle to almost the margin of frons)

Possible species C.pudorosa + C. Albicornis + C. Lineatipes
Based on the absent of a dorsal seta you mentioned before

Remember also......this is a female and discription of the females are very poor !!

Succes again....:D
Joke

Posted by Stephen R on 03-02-2010 13:19

#30

Excellent!

I checked the av under the scope, and it is definitely not truly ventral, so I think C. pudorosa is out (also the palpi are black to the base, not brown with yellow base). I thought albicornis at first, but then read in the description of lineatipes 'Frontal triangle ... rarely continuing as an indistinct greyish line in anterior half of frons' and thought this fitted better. Also the female C. lineatipes has 'fore femur often predominantly darkened', whereas in albicornis it should be yellow at least on the ventral side.

I did check the pvs, and they are long along the whole length of the hind femur. So I think everything fits for C. lineatipes :):) AND there is a pinned specimen in the Gallery which looks like a reasonable fit (including the pre-apical dorsal seta :o ).

Thank you again for your saint-like patience! I think we have a result :):)

Stephen.

Edited by Stephen R on 03-02-2010 13:33

Posted by Stephen R on 03-02-2010 16:13

#40

oxycera wrote:
PS
According to the British Check-list, albicornis and lineatipes are synonyms.

Thank you! MCE has a note on this (apparently suggested by Pont in 1986) and maintains that they really are distinct species with different male terminalia. Who knows?

Roger, I haven't touched a drop. Still waiting for that pint of single malt :D As for the diptera, I could stop any time I want. I just don't want to. (Monroe, 1959).

Stephen.

Edited by Stephen R on 03-02-2010 16:17

Posted by Stephen R on 16-07-2010 13:32

#41

After a lot of searching I yesterday caught 2 males in the same location which I believe are of this species: 4.5mm Clitheroe 15 July 2010.

It seems clear from the long narrow cercal plate that this specimen is of Coenosia albicornis. The coloration of the front femur seems to be strongly sexually dimorphic - all the many females I have seen have extensive darkening which seems to continue round the ventral side (though the book says this shouldn't happen). Both the males show darkening on the dorsal side only. Of course there is an outside chance that the females are of one species and the males of another, but I don't believe this! I have sent two females to Stephane, and if he agrees I will ask Paul to change the ident of my gallery photos to C. albicornis.