Thanks Jeff. It looks a lot like the images I found on the net, but most of the images were from other parts of the world. I did find this one from Samford University in Alabama.

We certainly see why Jeff called this Tmarus. Our spider reference - the World Spider Catalog list a half dozen species for USA (angulatus, floridensis, minutus, rubromaculatus, salai, and unicus) but angulatus seems most common (likely?). We checked out the image Jeff suggests as the male of the species , but it seems different enough to confuse us. Checklist of Kansas crab spiders says "Front of carapace strongly protruding, abdomen truncate with dorsal tubercle at posterior end." We don't see it, but maybe Kansas is just talking about the female. Great image and great ID.

is angulatus.
The males resting stance and leg formation (legs 1 and 2) are why I think it is Tmarus. The small shrivled abdomen may not be an accurate indicator.

Thanks everyone for the help getting the species on this spider. It's moved to the new species page.