Leech ID please

Malcolm Banks · #1 (**permalink**) 22-09-2009, 12:41 PM

Whilst pulling out surplus frogbit from my pond and checking carefully for any "residents" attached, I spotted this leech. I have checked many of the previous WAB threads on leeches and some other Net sites but cannot find an image that looks quite the same.
The leech was a dark olive green and had a distinctive, raised area on the posterior ventral region. I am guessing this is some sort of "brood patch" since, as I handled the leech, several tiny dark reddish worm like creatures (presumably leechlets

) moved from this region onto my hand (one can just be seen, out of focus, in the "u" of the leech.
So, I would be grateful for ideas on ID?
M

Malcolm Banks · #2 (**permalink**) 09-10-2009, 11:29 PM

Any leech boffins out there? I am still in the dark (didn't realise there were so many leeches) about this leech. So, I have posted a few more images in the hope someone may be able to help

M

Adam Cheeseman · #3 (**permalink**) 10-10-2009, 04:53 PM

You might want to check out Theromyzon tessulatum, excuse the spelling if it's incorrect.

Cheers,

Adam

Malcolm Banks · #4 (**permalink**) 12-10-2009, 01:28 AM

Thanks Adam, having seen some of your replies to leech threads before, I was hoping you would pop your head over the parapet. Your suggestion of Theromyzon tessulatum is an interesting one (and your spelling is spot on).
On the one hand, there is more than a passing similarity between my images and those of T. tessulatum posted at Google Image Result for http://www.biopix.dk/Temp/Theromyzon%20tessulatum%2000007.jpg

Looking at the yooung leeches in the T. tesselatum images, it would appear they are at a more advanced stage of gestation than my specimen. The dark patch on some of the images also appear to be on the dorsal surface, whereas the dark patch (I presume the "brood area") on my specimen were on the ventral surface.
What is rather worrying is that T. tessulatum (aka Duck leech) is a parasitic leech that causes serious disease and death in many forms of waterfowl. It has even been recorded as a zoonosis

( http://ukpmc.ac.uk/picrender.cgi?art...8&blobtype=pdf )

If it truly is T. tessulatum this begs the question of not only how it got into my pond, but how is it not just surviving, but breeding. I have never seen ducks in the pond and only ever once seen two ducks on the lawn some 30 metres from the pond. Anyway, rather than speculate I will try and find out more about this interesting beastie.
M