Researchers studying a 400 million year old bony fish from Estonia believe that they have found evidence for the origins of teeth. Using advanced synchrotron microtomography on numerous specimens representing different ages has allowed scientists a rare glimpse into the evolution and formation of teeth. As lead author Donglei Chen explains, “We can watch how fishes initiated and replaced teeth one by one, and how the blood vessels of these teeth were formed, 400 million years ago. It is as if we have traveled through a space-time portal to a living, microscopic world inside the fossil bones.” This research will be presented at the 77th Annual Society of Vertebrate Paleontology meeting in Calgary, Canada.