hunanensis likely looked like, Philip Donoghue, a professor of paleobiology at the University of Bristol in England, told Live Science. .Donoghue and his collaborator Xi-ping Dong, a professor in the School of Earth and Space Sciences at Peking University in Beijing, have examined many of these embryos over the years, but this is the first time they've found one with preserved brain tissue hidden inside.Historically, reports of scientists finding fossilized brain tissue have been controversial because it was once thought that nervous tissue couldn't fossilize, Live Science previously reported."That seems to me, inescapably, a tissue that is not muscle — and it's not gut either, so what could it be?" Strausfeld told Live Science.Compared with what the team typically observed, the embryo that contained traces of nervous tissue looked starkly different.
That embryo bore a clear, organized structure in its head, which the team interpreted to be the animal's ring-shaped brain.
hunanensis to animals like penis worms and mud dragons, scientists could reasonably expect its brain to be ring-shaped, so the authors' interpretation of the fossil makes sense, Strausfeld told Live Science.Notably, this is the first time fossilized nervous tissue has been found in a so-called Orsten-style fossil, the authors added.
Such fossils are usually less than 0.08 inch (2 mm) long, are found locked in nodules of limestone and are preserved through a mineralization process whereby the animals' tissue is replaced by calcium phosphate."The most interesting thing about our paper is perhaps what it tells us about the potential for future discoveries," Donoghue said.