I'm not a reviewer Cheetah, but that is a nice still-life. Watercolor, right? It does show that you can do realistic/believable light and shadows to convey form.
From what I've heard about the review process, you CAN include things in your application that wouldn't necessarily go in your AS gallery, like human figures to show that you can do anatomy. I don't think it's the -best- choice if you can do something more 'on-topic,' but I think as long as you also show that you can do anthros and whatnot, and you're just using this to show that you can also do lighting, you'll be okay.
Don't take my word for it, though- that's just my opinion on it. You'll want to get an actual reviewer cheetah to confirm it- and like I said, it'd definitely be better for you if you could apply the same principles to an anthro or animal.