can anyone identify this iguana?

when this iguana was a baby he looked just like the rest of the babys, bright green. the others, which were all the same size as him, are all about 2ft. long, but he is only about 15in. (due to a once broken tail, but now grown back) and he is very dark. I have no idea what type he is, so if you can give me any information on him it would be most appriciated.
thanks