Heloderma suspectum
Helodermatidae is the only family of venomous lizards in the world. Venom is secreted from glands in the lower jaw and delivered through grooves in the teeth.
This one is a juvenile and was only about 8 inches long, very similar in size to the one I photographed last week. This one was not as aggressive as the one from last week. Kind of ironic that it's taken me a couple of years to locate and photograph one of these magnificent lizards in Sabino Canyon, and suddenly I get a chance to see two of them in different parts of the canyon within one week. Very cool.