I'm clueless what I have here. It looks somewhat like a widow, but the stripe is orange, not red, and doesn't quite match the size and shape that I see on the various widows. It also looks something like an antmimic, but again the stripe seems too short. I'm including a second image, which shows a side view of the spider crawling down a rock. This view clearly shows white markings along its side, which are barely visible on the top view. It was very fast and I had a hard time keeping up with it to try to even get a photo. I blew on it a couple times to get it to stop just to get something. The habitat was lakeside on large quartzite boulders strewn along the shore and hillside. Any help would be appreciated.