Very clean, the only thing that bugs me is the back muscle... Just seems off... i dont know why. Otherwise I think this is a very good model and texture.
I think the issue is spines are actually more recessed, with the thickness of the back more around the actual shoulder joint. The center of the back should be more concave, where in your model you have it bulging outward too much.
Hehe, I always wanted to keep away from anatomy, but this character (my first which I make completely alone) is more like an anatomy study than a character for my game :-)
So, back and color variation are the next steps, thanks for the input.
Ha, you can't really get around anatomy with characters (unless you only draw mechanical things, like some crazy people...). It's one of those things where it's way easier to see that something is wrong than know what is right.