I’m thinking maybe deer pelvis. I’m guessing it’s a subfossil and not as old as the shark teeth you were after. As for preservation, it will probably flake as it dries out, so you could use a consolidant to prevent that. At the museum, we use something called B-72. Here’s a page with more info https://www.floridamuseum.ufl.edu/vertpaleo/amateur-collector/preparation/