Conodonts were tiny fish-like animals that were very abundant in the shallow seas of the Paleozoic Era. The animals were about 1/4 inch in length and had no hard parts except for their teeth. Conodont teeth are very common fossils in the Ordovician, Silurian, Devonian, Mississippian, and Pennsylvanian rocks in Kentucky. Conodont teeth fossils are microscopic and are studied by micropaleontologists, who use them to establish relative ages of the rocks in which they were found.
The conodont animals are probably descendants of the animals that gave rise to the vertebrates (animals with backbones) and are, therefore, distantly related to us. They became extinct during the Triassic Period.