Monitor Tegus and Dwarf Tegus =)

Just wondering if anyone knew anything about these guys. This is just out of curiosity, I saw some pics on a website, and when I tried to find info (because I had never heard of them) there was nil for both common and scientific names. The scientfic name for the monitor tegu is Callopistes flavipunctatus, and the dwarf tegu (which was particularly striking, actually :) ) is Callopistes maculatus. One very brief thread I found said they are a type of amieva, but they don't have the same genus or species name.