Dinghua Yang
A fossil fish found in Yunnan, China, has filled in a gaping hole in how researchers thought the vertebrate jaw evolved.
The 423-million-year-old specimen, dubbed Qilinyu rostrata, is part of an ancient group of armoured fish called placoderms. The fossil is the oldest ever found with a modern three-part jaw, which includes two bones in the upper jaw and one in the lower jaw. Researchers reported their find on 20 October in Science.
Anna Nowogrodzki, science writer 