I came across this spider, not far from a large tarantula dwelling (I saw and photographed him too) last night. They were on a rock, flat to the rock surface. We were shining a light on one and at some point one of them basically made a run right at us, which I was surprised by...
They were both about an inch in diameter. I came across them at the Phoenix Mountain Preserve in the Sonoran Desert near my house.
Any help would be much appreciated. Thanks!
These might be wall crab/flat spiders, Solenops spp. (family Solenopidae) - see http://tinyurl.com/ra397q for an example. They are ambush hunters that come out at night to lay in wait for something eatable to come along; they are harmless to humans.
