This spider was originally submitted to WhatsThatBug.com back in 2008 and since we really need images of it here, I contacted Daniel and he helped me get copies of the images to post here. Here's the original post at WTB: http://www.whatsthatbug.com/2008/01/18/fishing-spider-from-arizona-dolomedes-gertschi-perhaps/.

Note from the photographer:
"I found this strange spider in the Sabino Canyon near Tucson. It was June, nearly 110°, and the water ponds in the canyon bottom were decreasing at a high pace. Around one of the ponds some of these spiders were sitting and some had amphibia larvae in their fangs. Strange, they rather looked like giant crab spiders; the one on the photo also moved like a crab. Do you have any idea what that might be? Thanks a lot!
Greetings from Daniel Jestrzemski (who really enjoyed his time in the US Southwest)"