Sorry - haven't seen this as didn't get alerts while website access what down the past few days.
Has to be a stinkpot. Sternotherus oderatus The pictures are dark and can't see head/neck striping, but with the overall look and seperations in the plastral scutes, has to be sternotherus. With the absence of keel, dark coloring, and pointy nose - odoratus.
It's a little mud turtle, it's full grown too. I'm not familiar with proper or specific names but I used to catch them all the time in the creeks of east Texas as a good, as hatchlings their the size of a coke bottle lid. Not sure of regulations on selling them.