sojr's picture

Amaurobius similis?

Observed: 7th November 2013 By: sojrsojr’s reputation in Invertebratessojr’s reputation in Invertebratessojr’s reputation in Invertebratessojr’s reputation in Invertebrates
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mattprince1969's picture

I've agreed with you...

..though I can't see enough detail on the epigyne to rule out a.fenestralis, it is likely to be a.similis.

In IMG_1778 the cribellum can just be seen ahead of the spinners. If you focus on that area you can see a wide slot which when viewed clearly is split down the middle.

The following excellent macro from 'Horizontal Dave' on WildAboutBritain shows the organ very clearly.

sojr's picture


Cheers for the details & link Matt, much appreciated. I've taken a clearer shot of the epigyne which is as good as I can get or see through a hand lens. Don't know if that'll help. (I've now released the spider back outdoors!)

Rich Burkmar's picture


I agree with Matt. You've taken a reasonably good picture of the epigastric area, but I'm not convinced that it's a mature female. I'd expect to see a bit more structure towards the base of the epigyne than I can see here.

Rich Burkmar

sojr's picture

Cheers for the input Rich, I

Cheers for the input Rich, I had a feeling it was an immature despite the size. Just couldn't make out the epigyne any clearer than a hairy patch!

mattprince1969's picture

You may well be right..

Its not always easy to tell with amaurobius because of the hairs that obscure the epigyne.

The legs look just a little translucent so I wouldn't want to bet against Rich on this one.

What is good with your new shot is the cribellum , which is clearly visible just in front of the spinners. To see that its divided you need to look at it from behind.

If you want to be absolutely certain of a species then the males are easier, as you can concentrate on the palpal apophyses from above...

sojr's picture

I did wonder if that (the

I did wonder if that (the cribellum) was what I could see but didn't feel confident enough having never used that part of the body as an id 'marker'

mattprince1969's picture

the cribellum is useful

The cribellum is a difficult one in the early part of the family key - but it is useful for the split between amaurobius and coelotes which are easily confused as a beginner (in my experience).

(The FSC key to families is a better starting point than Roberts btw)

sojr's picture

Thanks for all your help,

Thanks for all your help, I'll have to look up that Fsc key.