Yunnanozoans Are Oldest, Most Primitive Stem Vertebrate, Says Study

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. Vertebrates include all mammals, birds, reptiles, amphibians, and fish but the vast…