A fascinating morning spent at Kerne Bridge on the Wye with Cyril Bennett of the Riverfly Partnership looking for the "country's rarest upwinged fly": Potamanthus luteus. It also used to breed in the Usk but now is only thought to exist in the Wye.


The nymph is, like the Mayfly, a silt burrower but completely different looking.



The dun is similar to a Yellow May, hatching from early June, but the three tails, brown streak along the back (as the nymph) and clear spots along the side of the body give it away as something rather unusual.



I would be interested to hear of any sightings to establish its current extent.

P

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Trout fishermen revere the trout; trout, on the other hand, unaware of their sublime standing in man's world, revere nothing, including man, a creature they seem to view with special contempt. Nihilism is a rare trait in fish but trout are full of it. The old men liked that.

Bill Griffiths, the ghillie at the Carrots, and I, saw the dun only this week. Bill asked me "What type of fly's that?" as neither of us could recognise it. There aren't many around. The dun was actually perched on the wing mirror of our vehicle.

I have seen them occasionaly, usually in full sunlight on warm days and usually during the day. Now that I know what to look for, I'll keep you posted.

Johnny

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I won a £1,000,000 and spent most of it on prostitutes, drink,trout fishing, cars, cocaine, cigars and the rest I wasted...

Not this fly but I saw a couple of specimens of a fly at Tregate yesterday that were new to me. Unfortunately I couldn't get a photograph but it was a large spinner, getting on for danica spent size, which had a very distinct yellow blob towards the head and appeared to have over large wings. Any ideas?

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“There is no more lovely country than Monmouthshire in early spring. Nowhere do the larks sing quite so passionately, as if somehow inspired by the Welsh themselves. There is a blackbird on every thorn and a cock chaffinch, a twink as they call him there, on every bush...... It moved me profoundly. I had been spared to see another spring, and I thank God for it.”

Oliver Kite
“A Spring Day on the Usk”
A Fisherman’s Diary

Quote/
It also used to breed in the Usk but now is only thought to exist in the Wye.


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Cricky, not only is it rare then its a tenacious little beast if it can survive the Wye water and not the Usk.!

Seekit - previously Seeker.

thanks, Macsas

dunno, Paul - will think on't

takes one to know one, Geoff

__________________
Trout fishermen revere the trout; trout, on the other hand, unaware of their sublime standing in man's world, revere nothing, including man, a creature they seem to view with special contempt. Nihilism is a rare trait in fish but trout are full of it. The old men liked that.

Well done Mr. P,it's all downhill now then - at least up to the point where you discover a previously thought to be extinct species!

I hear there may be a population of Yellow Mayfly on the upper Taff, perhaps the Merthyr boys will keep a look out for this one - something for Gareth L's MTAA website perhaps?

PS
Background much improved, good effort.

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Musha rig um du rum da

Just to be pedantic I believed Arthroplea congener Britain's rarest.


Potamanthus luteus is rather larger than Heptagenia sulphurea (Yellow May Dun) which it resembles; however both duns and spinners differ from that species in having a distinct brownish stripe running the length of the body dorsal surface.
According to Prof J R Harris (Trinity College, Dublin) they have been found on a few occasions in the south of England on the Thames in July.


The photo certainly fits Kimmins' description with its brown stripe. I'll now keep an interested eye open when I visit the area at the end of this month.

A quick internet check didn't reveal much. However this was interesting:

http://nabs.confex.com/nabs/2007/techprogram/P1044.HTM

Luteus is Europe's only member of the Potamanthidae.
Knopp & Cromier's 'Mayflies', an US publication list several Anthopotamus species. I suspect the genus name has recently changed.



EDIT: Only changed for the 4 North American species.

Having looked through the various guides it seems that a female pale watery spinner might fit the bill in most respects, especially with its bright yellow eyes that fit my description. My only problem would be that this species should be smaller than the fly that I saw. It certainly seemed bigger than any other fly that it was in company with however I might have been generous with the original estimate on size.

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“There is no more lovely country than Monmouthshire in early spring. Nowhere do the larks sing quite so passionately, as if somehow inspired by the Welsh themselves. There is a blackbird on every thorn and a cock chaffinch, a twink as they call him there, on every bush...... It moved me profoundly. I had been spared to see another spring, and I thank God for it.”

Oliver Kite
“A Spring Day on the Usk”
A Fisherman’s Diary

you don't make it easy, Paul

there's a big size difference between a Mayfly and a Pale Watery!!

__________________
Trout fishermen revere the trout; trout, on the other hand, unaware of their sublime standing in man's world, revere nothing, including man, a creature they seem to view with special contempt. Nihilism is a rare trait in fish but trout are full of it. The old men liked that.