We found a skeleton July 4th on the rocks next to the Stones River East Fork in Rutherford County, Tennessee. The skull was missing. There were four or five FLAT "ribs" about 1 1/2 inch wide  and 3 to 6 inches long. Where they joined were protuberances or ridges. Connected to the last "ribs" was a triangular shaped "pelvis" that had a small round hole on each side at the pointy end. Connected to that was a curved "tail" that looked like a typical mammal's spinal column. The "ribs" section was maybe 14 inches long, the "pelvis" 7 inches long, and the "tail" 20 inches long.
This wasn't an old skeleton. It didn't seem to have been there for more than a couple of weeks. A few hours afterward, we both drew sketches of it and we saw the same thing. What could it be? There are farms along this stretch and alligator turtles and gar and of course catfish, but none of these seem to fit.