more mystery spiders

[Immortal_sin]

here are two mystery spiders that Mark brought home for me. Unfortunately, all he had was a coke bottle, and they seem to have drowned in coke
I took pics, but my macro sucks on my camera...maybe someone can at least give me some idea though?
The black one is first..built like a widow almost. The specimen he brought home he said was much smaller than the ones he's seen. The brown spider also is a smaller specimen. He says that one gets up to about 2" in legspan.
They are everywhere where he is doing a construction job on a house. BTW, we are in western Oregon, if that helps.
I'm posting the black one first

 

[Immortal_sin]

here's another shot of the black spider

 

[Immortal_sin]

and now for the brown colored one, it's got an interesting pattern on it's abdomen, which probably won't show up here

 

[Immortal_sin]

2nd pic

 

[Arachniphile]

The first spider is from the same family as the Black Widow, Theridiidae. The best I have been able to identify this spider is Steatoda grossa. I have heard it refered to as "False Widow", but that could be tagged to many memebers of that family.
They are quite common in the Pacific North West, but I don't know if they range farther than that. If you look at them from the right angle thier eyes will shine like tiny diamonds.

My best guess for the second spider is a trap door species.

 

[Wade]

Does the black spider have sort of creamish colored markings on the sides of the abdomen? I have some very simmilar widow-lookalikes. As Arachnophile suggested, S. grossa is a good guess, I think mine may be that species, or at least genus. Acording to Levi and Levi (Spiders and Their Kin), S. grossa is "cosmopolitain" in distribution, meaning they're pretty much everwhere.
The second one is trickier...no doubt Alex is working on that, even as we speak

Wade

 

[Alex S.]

Hehehe, here I am

I agree on the first one with Wade and Arachniphile, that it is most likely Steatoda grossa, which can get almost .5" in body length.

The second spider looks to very possibly be of the family Atypidae (purseweb spiders). The cephalothorax, chelicerae, and other body structures look of the family.

Alex S.

 

[Big Mike]

You gotta love it. North America has some of the coolest arachnids!

Big Mike

 

[Immortal_sin]

thanks everyone!
Mark was worried about the black one, he was just sure it's a form of black widow, and very venomous. I told him that it's not. He says there are literally THOUSANDS of them underneath this house he's working on.
And some of them are huge, as are the other brown ones. Do the pursewebs make a web that looks like a sheet? Like a solid web, not an orb? He says there are tons of web sheets too, but that the spiders on them are very tiny.
I told him to capture more, and to make sure this time and empty ALL the coke out of the bottle first

 

[Alex S.]

Atypidae

Purseweb spiders make a tube-like web that extends vertically up the side of an object. It is a solid type of webbing. The spider inhabits the inside of the tube and when an insect lands on the outside of the tube, the spider then attacks it through the webbing and pulls it in. This is why purseweb spiders have such large chelicerae. The tube-web can be anywhere from 6" to 18" long, depending on the species.

Alex S.

 

[Immortal_sin]

thanks Alex, then he must be seeing a 3rd type of spider there too...
What about the false widows, what kind of webbing do they make?
Is there a good site on the net about these types of spiders?
thanks!
Holley

 

[Alex S.]

Hey Holley, the false widows make a web very similar to the Latrodectus (widows), since the false widows and widows are in the same family (Theridiidae), but the false are not dangerous.

As for sites on the net and such, I suggest typing keywords like, false widow, widow, Steotoda, Theridiidae, purseweb spiders, Atypidae etc. into a search engine.

I'll be looking forward to more "mystery spider" photos

Alex S.

 

[Arachniphile]

Holley,

As ALex said the S. grossa has a web almost identical to that of a Black Widow. They tend to find a location between points and "fill the void" with random, paternless, cross sections of webbing inteded on entangling prey. These spiders are harmless.

You are absolutely right about there being a third type of spider there, and I would say several more than that as well. Most likely there are several members of the Tegenaria, the funnel weavers, under there as well. There are atleast 5 different species (that I have seen) of this genus that are quite common under just about every house in Oregon. Yes, it is more than possible that there are Hobos under there, which is the T agrestis. The Tegenaria are the ones creating those "sheet webs". If you look there will be a "funnel" at one end of the web which is where the spider spends a great deal of its time waiting for prey to stumble or fall into it's "net". All species of Tegenaria, save the T. agrestis, are harmless as far as toxicity goes. What I would like to point out about the hobo is, yes, it's bite can be painful and have some very undesireable side effects. BUT it is quite unlikely that it will impose any serious or lasting effects other than discomfort. I have read on several papers about this spider that they more frequently administer a "dry" bite as a defense rather than wasting precious venom. Of the bites where venom was injected it was said that only a small percentage of those developed the most severe of symptoms. This is by no means a standard, but rather some keen observations by others much more qualified than I, I just have done my homework...

Please do post pics of any spiders that need identified, I find it quite challenging and I always learn something I didn't know.