Xysticus epigynes

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Xysticus epigynes

So, I've got a spider that looks like a female Xysticus cristatus, and that's dead common so it's probably what it is. However, I'm trying to rule out the other species properly. I think I can rule out most except X kochi and X ulmi. But to clinch the deal, I apparently need to make reference to the epigynes.

Unusually, I can see the epigyne on this one pretty well (even with it still being alive it's quite cooperative). But I'm pretty confused about what the differences are. I've got the Collins spider guide by Roberts, which has drawings and helpfully tells me that the epigyne of both kochi and ulmi are "distinctive". Hmm. I've also googled images of the epigynes of all three, and am still pretty flummoxed on what the differences are.

As far as I can see, there's a pair of holes, with a column-like thingie separating them. Not sure what else I should be looking at. 

Does anyone have advice? Perhaps there's a handy online guide somewhere?

Thanks as always



Must admit I find Xysticus very confusing on the few occasions that I've tackled them, which of course means I'm not a very good person to be offering advice, but have emailed you some text from the big Roberts guide. I suspect that this is a genus where specimens really are needed to make progress.

Thanks Martin, much

Thanks Martin, much appreciated! Spiders - they always seem so exciting, then are almost always so flippin difficult!

Thanks Chris - handy sites

Thanks Chris - handy sites indeed, but I still find epigyne diagrams baffling. More practice required I guess...

I would tackle spiders by

I would tackle spiders by starting with the males. The male genitalia diagrams make so much more sense than the epigynes!

ignore Roberts use of the word distinctive

Xysticus is not an easy group and you won't get far with attempting to id live animals (well you might with some of Graemes mega's, but not with the commoner cones) ~ the differences can be subtle and are often obscured by hairs etc. 

Ignore Roberts reckless use of the word distinctive ;)


Thanks all. Love the

Thanks all. Love the description "reckless" - highly appropriate it seems!