Hello,

You have a male Great Basin collared lizard there. My guess would be collected from Nevada. I do notice that his tail is slightly thin. These wild caught collareds will go down hill fast if there stressed out and there captive needs are not met. It sounds like you have the right idea with the size of your enclosure and vapor bulb. If you have anyway to get him some natural sunlight for a period of time that would benefit that little guy the best. I would also soak him in a little water and let him hydrate.