I've been trying to figure this one out for a couple of weeks now. I called Prehistoric pets and the person I talked with did not know what it was or where it came from. So, I then emailed them asking for more pictures. They sent me a plastral shot and a partial head shot showing the underside and right side of the neck and head.
It could possibly be a Chinemys X Mauremys hybrid of some sort. But I'm almost possitive that it's Chinemys nigricans. It's definately not Orlitia, Rhinoclemmys, or Sibenrockiella.