Sistrurus tergeminus — Western Massassauga
Subspecies I've seen:
S. t. edwardsii
Sistrurus tergeminus edwardsii — Desert Massassauga
I was looking for herps on the road at night with Rick McCarthy, whom I had met in a campground in the Chiricahua Mountains. We were both very much hoping to see this species, which is difficult to find in Arizona. We saw a small snake moving on the road, but before we got out to identify it, I noticed that it was awkwardly dragging its tail, and I realized that it had been hit by a car. Then we realized it was the snake we had most been hoping to find, and we were very sad.