I saw this critter outside my apartment in Ann Arbor, MI tonight. I have lived in Michigan for 22 years and have never seen this before. Though I recently moved to Ann Arbor from near Detroit. There are a lot more trees and rivers here. There is about an 8 foot wide stream about 100 feet from my front door so I assume that is where they live. I saw all the photos but this once seems to have good detail of the wings if you want to use it. It took ten tries to get a clear picture at night.
The female Dobsonfly can be identified by her far less impressive, but considerably more formidable mandibles.