Scientists Offer New Theory for Evolution of Human Skeleton

For years, there was a scientific consensus that origins of the human skeleton had its roots in extinct predatory creatures known as conodonts -- eel-like beings that lived between the Late Cambrian and Late Triassic periods.

But new research published in the journal Nature suggests that the human skeleton and all of its characteristic bony tissues did not evolve from conodonts. The conodonts, the researchers contend, evolved independently of other vertebrates, rather than sharing any evolutionary lineage.

The origins of the human skeleton, on the contrary, can be traced to the armor of ancient mud-slurping creatures who evolved the armor to protect itself from predators such as the conodonts.

By studying ancient skeletons with high-energy X-rays, a team of paleontologists from University of Bristol, Peking University and the US Geological Survey were able to show that the tooth-like structures found in the mouths of conodonts evolved within their own evolutionary lineage, rather than in an ancestor shared with other vertebrates.

"We were able to visualize every tissue, cell and growth line within the bony teeth, allowing us to study their development. We compared the tooth-like skeleton of conodonts to that of their 'paraconodont' ancestors and to teeth in living vertebrates, demonstrating that the tooth-like structure of conodonts was assembled through evolutionary time independently of other vertebrates," said the lead study author Duncan Murdock of the University of Bristol.

Philip Donoghue of the Department of Earth Sciences at University of Bristol said: "This removes a key piece of evidence from the hypothesis that teeth evolved before the skeletal armor, and suggests that the common ancestors of conodonts and other vertebrates likely lacked a mineralized skeleton. Rather, it seems that teeth evolved from the armor of our meek filter-feeding ancestors."