Only herps I have seen so far this year are a few small black racers and garter's. Unfortunately they were attempting to warm up on the warm road surface and had met their demise. It will be another couple mounths before the Diamondbacks come out to play (I'm not talking spring training here). I generally see a lot (read that as WAY TO MANY) of them when out running the trails. Last year was an exception with 0 sighted. They tend to be most active here when the temps stay between 85 and 95. Any cooler and they are inactive usually coiled on rocks trying to warm up and any hotter and they are smart enough to seek shade (I should learn this some day).
Other reptiles I have come across are lots of lizards including Horned Toads and a few Gila Monsters (the only venomous lizard natural to the U.S.).
Also have seen many coyotes, javelina, deer, a couple of desert big horn sheep (very rare) and a very large mountain lion! This is over the course of about 15 years of trail running.