It looks like a modern snake vertebra.

Snake vertebra are fairly rare, unless they're still in the snake.

I have a few fossil snake verts. The majority that I have found are sea snake verts from the Eocene, but I have found a couple from Pleistocene land deposits. The land verts came from deposits that seem to have been swamps. If you think about it most snakes live on land in dry areas which diminishes their chances of becoming fossils. Snakes are tasty treats for a lot of land carnivores as well as birds of prey which also greatly diminishes their chance of becoming fossils. Snake vertebra are fairly fragile so they can be easily crushed, dissolved in acidic ground, or eaten by small rodents for their calcium content. Rodents looking for calcium is one of the reasons that you don't often see antler sheds laying around in the woods. The reason fish bones are relatively common is that they are deposited in water and are covered up by mud or sand which helps to preserve them, and even if 99% of all fish bones don't fossilize there will still be a lot of fish bones just due to the fact that there are a lot of fish constantly dying and leaving bones in the mud.

I don't have any snake verts posted, but I found a site for you to look at. There is a super fossil snake at this link. http://www.sheppeyfossils.com/pages/julians_snake.htm