423-million-year-old fish fossil sheds light on evolution of animals’ jaws

A 423-million-year-old fossil is rewriting the history of how jaws evolved, according to a team of Swedish and Chinese researchers who published their findings Friday in the journal Science.

The fossil was discovered in China’s Yunnan province and belonged to Qilinyu rostrata – a bottom-dwelling, armored fish that belongs a prehistoric class known as placoderms. Although scientists have believed placoderms to be an evolutionary dead end, this fossil’s jaw bones suggest the fish could have played a key role in vertebrate evolution.

“Anything from a human being to a cod has recognizably the same set of bones in the head,” study coauthor Per Ahlberg, a paleontologist at Uppsala University in Sweden, told Science News. “Where did these bony jaws come from?” READ MORE.