This is a fossil dugong (Metaxytherium Floridanum) rib section that was recovered from the Peace River in the Bone Valley formation of Florida (Miocene Period, approx. 7-14 million years old). This is a long section that shows the natural curvature of the rib cage. This piece measures approx. 6 inches in length and is very heavy.
Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown.