This is a great photo, but appears to be let down by the fact that you are saving the image with too much compression. This has introduced artefacts around some of the edges. If you're interested, there's an article in the tutorial section on how to use Photoshop to prepare images and it covers saving jpeg files to make the most of the 150k limit available to us. Even though you might not be using Photoshop, similar actions are available in other (some even free) image editing applications.
But now for some comments on the photo:
I think that you have picked a very interesting subject, which many people may never have seen before. This should do well in this challenge. The lighting of the subject is very good - with no obvious bright or distracting hightlights. The background colour compliments your subject well. Despite the jpeg artifacts I mentioned earlier, I think that this image still holds up extremely well against the rest of the competition.
Looking at this for the third time now I know what it is that bothers me - it looks way oversharpened in sme parts and left alone in others. The detail looks applied rather than shot.