Yunnanozoans Are Oldest and Most Primitive Stem Vertebrate, Researchers Conclusively Identify

A group of scientists have identified that the fossil records of yunnanozoans, an extinct creature that lived 518 million years ago in the Cambrian Period, are the oldest known stem vertebrates. Stem vertebrates refer to creatures that were vertebrates, i.e. possessing a spinal column, but have now gone extinct though have closely related living vertebrates.