aside from making the jaw thicker and making the eyes a little bit smaller, the only thing i can really think of is that b/c you used a female sprite as the base that might be affecting how you're perceiving it if that makes sense. maybe a few more variations to differentiate it would help? maybe adding more white underneath the snout/making a trail, to give the illusion of a thicker neck?
idk if any of this is what you're looking for or helping at all tho