Conodonts have been studied for almost 150 years, but for most of that time, nobody knew what animal they came from, although several possibilities were proposed - they were only ever found as isolated elements or as small assemblages.
In the 1980s some exceptionally well preserved specimens from Scotland emerged which showed the conodont animal with teeth in situ.
These incredible specimens showed that the conodont animal was a small eel-like animal that lacked a proper jaw yet had an assemblage of tooth like elements inside its mouth for either filter feeding or catching food items.
Because it has a dorsally located stiffening rod called a notochord and block like arrangement of muscles these animals are taxonomically placed within the vertebrates. However their exact relationship to other vertebrates is still not fully resolved.