Identification of this spider?

Question

I find these in forests in Oregon, western half, though they're probably on the eastern half as well. They live under pieces of wood and bark, and have a small web across the ground. Mine will eat crickets, but I think they eat carpenter ants, termites, and maybe pillbugs/sowbugs. It seems about an inch long, red on the thorax and legs, and dark grey and slightly hairy on the abdomen. The closest to this spider I've found is sowbug killers -- they're in my backyard, but they're smaller then this spider and also are a light tan on a hairless abdomen, with lighter colored legs. The fangs also seem different shapes but I'm not sure about that.

Answer 1

This is very likely a species in the Amaurobiidae superfamily, and I agree appears to be Callobius severus (the hackled-band weaver or the hackledmesh weaver).

^{Source: Bugguide.net}

^{Source: Kyron Basu 2012}

Moldenke et al. 1987 provide a key to spiders of the Pacific Northwest. Importantly, they note:

adult genitalia are necessary for identifying species and separating Callobius from Amaurobius.

• For example, here is a picture of Amaurobius ferox (Hackledmesh Weaver)

^{© Danny Steaven 2008}

• I've seen numerous sites conflate this species with C severus and actually I've seen sources that identify them both as the "Hackledmesh Weaver".

So although the OP's specimen strongly resembles Callobius severus, a scope is necessary to truly identify to species. This Penn State page provides good information regarding these similar looking species in the superfamily.

Callobius and Amaurobius species have similar life histories and behaviors. They are most often found in damp locations under bark, leaf litter, and stones, as well as in woodpiles and other protected areas.

Stephen Ellis Lew (2011) produced an atlas to the genitalic morphology of the Callobius genus, and he proposed a morphological diagnosis that is more consistent with principles of homology than those previously in use. [See the link for his dissertation on the subject].

Callobius severus

Description:

• Cephalothorax and legs = reddish to dark brown [Source].
• Abdomen = dark to light grey with fine hairs; often with large, bilaterally mirrored paler spots.

Ecology:

• Nesting woodland species commonly seen in the Pacific Northwest

• McIver et al. (1990) suggests that this species of spider is one of many that is characteristic of young forests.

Is it Dangerous?:

• Not according to this Penn state website:

The one verified record of a bite by an immature Callobius species resulted in pain, itching, swelling, redness, and nausea.

• Vetter & Antonelli provide evidence for how to differentiate this species from the "more dangerous" hobo spider.

  

in the side view, the palp of Callobius males has large, conspicuous, pointed projections (Fig. 7).

Answer 2

It look like Callobius severus to me.

Answer 3

I agree with the above that the spider is probably Callobius severus, especially since you found the spider in a forest in Oregon.

The spider in found in parts of the United States and Canada with nests most widespread in the U.S. state of Washington and the states bordering Washington, making them most common in America's Pacific Northwest region.