Diptera.info

Posted by Juergen Peters on 26-11-2008 11:38

Hello, Roger!

rogerthomason wrote:
Found wandering around at Scatsta Airport. What's its name?

It's a male Amaurobius (Amaurobiidae), most likely A. similis (often in houses).

Posted by Smoggycb on 26-11-2008 15:58

If the white on the palps is not an artifact of the flash, then this is A. ferox (see image here http://www.afblum...aufero.JPG). The other two British species don't have this.

Edited by Smoggycb on 26-11-2008 16:03

Posted by Roger Thomason on 26-11-2008 17:50

Thanks Juergen and Chris for your replies. Those white marks on the palps are present on this spider, and look like teeth or claws which are retracted. Can't show a close up as this system only allows 1 photo per thread:(. which is why I am sending split images. So this will be A.ferox then?
Unless J.B. pipes up again:D. This is not on my Checklist
Regards Roger

Posted by Smoggycb on 26-11-2008 17:59

If those white marks are there (it's actually the palpal 'bulb', the part of the palp that contains the working parts like sperm ducts and the like), then this is A. ferox - congratulations!

Posted by Juergen Peters on 27-11-2008 01:13

Hello!

Smoggycb wrote:
If the white on the palps is not an artifact of the flash, then this is A. ferox (see image here http://www.afblum...aufero.JPG). The other two British species don't have this.

Maybe A. ferox is much paler in Britain. Here at our house (both species are abundant) A. ferox is mostly very dark (often nearly black, the opisthosoma markings scarcely visible - and differently shaped). A. similis is mostly light brown like Roger's spider. In the key from http://www.araneae.unibe.ch/ the white on the palps is not mentioned as characteristic for one species (?).

Here some (confirmed) A. ferox and similis from our house in northwest Germany (A. fenestralis mostly only occurs in the forest here and is much smaller/more fragile):

A. ferox male:
http://insektenfo...adid=14056
A. ferox female:
http://insektenfo...adid=20589
A. similis males:
http://insektenfo...adid=11374
http://insektenfo...adid=11494

And for completeness: A. fenestralis:
http://insektenfo...enestralis
http://insektenfo...enestralis
http://insektenfo...enestralis

Posted by Smoggycb on 27-11-2008 09:05

All the specimens of A. ferox I have seen before have also been very dark, but certainly in Roberts 'Spiders of Britain & Northern Europe' the illustration of male A. ferox looks closer to Roger's spider than to other males I have seen, as does the spider in the link (on my first entry) above. And both Roberts and Jones 'Spiders of Northern Europe' mention the conspicuously white palpal bulb among British Amaurobius. My knowledge is limited to the British fauna, so maybe there are other white-palped species in Europe. If in doubt, catch it and get it under a micropscope if possible!

Edited by Smoggycb on 27-11-2008 09:06

Posted by Roger Thomason on 27-11-2008 15:07

Oh dear, seems like there's disagreement among the ranks :|.I've looked at photo's of both species and it does look more like A.similis but even among those there are variations. I suppose we could come to a compromise and call it Amaurobis sp., or you guys could have a fight in a carpark of your choosing :). I could make a few quid on ticket sales...hmm, I do need a ring-flash for my camera....