A sulcatta is also known as an african spur thigh. They get gigantic. The reason I suggested it may be a sulcatta is the similarity in the shell.. My eyes aren't real good so I can't see it real well. You can look them up on line. Sulcattas are commonly kept as pets and almost as commonly dumped when they get to large to house easily. There are several sulcatta breeders in the states. You can see them sold by the dozens as hatchlings at any reptile show of any size.I have always wanted one. I also have a box turtle, but thought you were inquiring about the big guy.
Have a great day