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Photo#606625
red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings

red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings
Madrona Marsh Preserve, Torrance, Los Angeles County, California, USA
April 5, 2011
Size: ~ 4 mm
Is this a male gnaphosid ?
And if so, any suggestions toward genus are much appreciated !

I've seen this species more than once; some with darker carapace, some with lighter colored legs, and some with more elaborate dorsal pattern consisting of two curved lines of beige crescents.

I'm also curious as to why the spinnerets are not visible on some gnaphosids.

Images of this individual: tag all
red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings - male red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings - male red-brown Spider with smooth, shiny carapace; abdomen furry dark grey with obscure beige markings - male

Moved
Moved from Spiders.

Moved
Moved from ID Request. Most ground spider do have the spinnerets visible. I don't think your spider is a ground spider. I'd guess it's one of the Hacklemesh weavers. Where do you usually find them?

 
Amaurobidae looks good, Lynette !
I usually find them running on the ground/sand/trail.
But that habitat seems to be shared by Gnaphosids & Amaurobids.

We only have records for three Amaurobid genera in Southern California: Amaurobius, Callobius, & Zanomys.
Our Callobius species are big with body lengths about 1 cm and up.
Our Zanomys species are tiny; all but one with body sizes under 3 mm.
That pretty much leaves Amaurobius, with five species recorded from Southern California, of which two from L.A. County.
A. latescens is quite big (8 to 12 mm) and A. agastus about right (female: 4.8 mm).
I unfortunately don't have access to Leech's 1972 publication, but, if it is indeed an Hacklemesh Weaver, it looks like it has to be A. agastus, based on size alone.

 
Amaurobius agastus
Well now we just need to find a resource with species description to confirm that. Nice research. I don't have Leech 1972 either.

 
Leech 1972
I bought a used copy from Tom Fasulo at Univ. of Florida. He has them listed on Amazon here: http://www.amazon.com/gp/offer-listing/B0006C6YKW/ref=dp_olp_used?ie=UTF8&condition=used. It's a good one, I use it a lot. Pretty much the main revision for Amaurobiidae.

Here's the description of the male A. agastus (from pg.75):

Male: Color - carapace uniformly orange. Legs slightly paler than carapace. Palpi, except for darker tibiae, same as legs. Chelicerae same as carapace. Endites of palpi and labium very pale orange. Sternum yellow, brighter than coxae. Opisthosoma (abdomen) gray streaked. Dorsum marked with 2 pairs of pale spots anteriorly, with incomplete chevrons posteriorly.
..Structure: total length 4.8mm. Carapace 2.55mm long, 1.7mm wide. AME smallest eyes, lateral eyes largest. AME slightly more than a diameter of one AME apart. ALE almost twice as large as AME.
..Distribution: Orange, Monterey, Riverside, & San Diego Counties, California.

Seems sort of fitting, actually.

 
Thanks for the link
I just bought the last copy. =] Do we think this evidence is strong enough to create a guide page?

 
Nice
Glad he had one left! Hmm, I'm not confident of the ID right now... I don't now enough about what the other species look like (not sure that species lists are always 100% accurate anyways... they are only records of the specimens that were collected, so that doesn't mean other species are not in the area, at least that's what I assume most of the time).

I'll email Robin Leech with a link to this page and see if he can help or has any pointers.

Emile, do you happen to have any more images that might show the palps in more detail?

 
Thanks a lot Mandy !
For your help in figuring out this little fella and for the description of the male A. agastus !

And yes, it would be great if you could ask Robin Leech if he would be so kind as to have a look !

I've added a few photos that hopefully show a wee bit more detail on the palps.
Let me know if you'd like me to crop them further around the palps, although there is not much resolution left to play with.

I can also post images of two other specimens, that show different dorsal patterns.

 
From Dr. Leech
Robin's reply was what I think we were expecting: "It could be A. agastus. However, we need to see the palpi to confirm."

Even in the additional shots, I'm not able to see the palpal tibiae in any detail (that's the part we'd need to see in great, even microscopic, detail), so not sure we can confirm anything in this case, sorry. The palpal tibiae of the Amaurobius spp. have branched apophyses that are uniquely shaped in each species. Since Robin said "could be A. agastus," I assume that would mean that at least the genus is right, though. I'll ask around and see if anyone has some images of confirmed A. agastus that we could compare to. Maybe if this one looks exactly like them, it wouldn't hurt to create a new species page for it (pending others' opinion, of course).

 
..
Better yet, simply capture the specimen so that we can get a closer look at the pedipalps under a microscope!

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