Yesterday Paul Murdoch sent me this photo of vertebrae that he collected at the Lee Creek Mine in North Carolina. They were all found together in a block of sediment, most likely the Early Pliocene Sunken Meadow Member of the Yorktown Formation.
These are the tail vertebrae from a whale, most likely a large baleen whale. In fact, the five small vertebrae at the top are the very last bones in the backbone. The last few vertebrae in a whale’s tail are modified to have a rectangular rather than round shape; these are the vertebrae that support the large flukes at the end of the tail that the whale uses for swimming (the flukes themselves are made of soft tissues and don’t fossilize.)
As large as these vertebrae are, they are from a very young whale. Notice the separate plates of bone sitting on each vertebrae; these plates are called vertebral epiphyses. In a fully grown animal the epiphyses fuse to the main part (the “centrum”) of the vertebrae. Moreover, in whales the epiphyses don’t all fuse at the same time. The first ones to fuse are in the neck and the tip of the tail. In this specimen we have loose epiphyses all the way to the tip of the tail, indicating that the whale was very young when it died.
Thanks to Paul for sending us the photo of these interesting vertebrae.