The discovery of a 423-million-year-old fossil in China has shed light on the evolution of the tripartite (three-part) jaw, revealing a previously unknown stage of jaw evolution in placoderms, an extinct group of early fishes. Life reconstruction of Qilinyu along with Guiyu and Entelognathus in Silurian waters. Image credit: Dinghua Yang. Jaws are an iconic and defining feature, not only of our own anatomy but of all jawed vertebrates. Jaws first...
