Paleontologists have traced the origins of humans and other vertebrates to a worm that swam in the oceans half a billion years ago, said a study published Monday.
A new analysis of fossils unearthed in the Canadian Rockies determined that the extinct Pikaia gracilens is the most primitive known member of the chordate family, which today includes fish, amphibians, birds, reptiles and mammals.
The research published in the British scientific journal Biological Reviews identified a notochord or rod that would become part of the backbone in vertebrates, and skeletal muscle tissue called myomeres in 114 fossil specimens of the creature.
They also found a vascular system.
“The discovery of myomeres is the smoking gun that we have long been seeking,” said the study’s lead author, Simon Conway Morris of the Cambridge University.