Ancient fish highlight the strangeness of our vertebrate ancestors

My, what small teeth they had.

A newfound treasure trove of ancient fish fossils unearthed in southern China is opening a window into the earliest history of jawed vertebrates — a group that encompasses 99 percent of all living vertebrates on Earth, including humans. The fossil site, dated from 439 million to 436 million years ago, includes a revealing variety of never-before-seen small, toothy, bony fish species.

The diversity of the fossils at this one site not only fills a glaring gap in the fossil record, but also highlights the strangeness that such a gap exists,…