The first jaws: A fossil fish helps to explain how jaws first evolved

Dinosaurs were once widely considered an evolutionary dead end without much bearing on the evolution of living animals. Yet, today it is clear that theropod dinosaurs gave rise to birds, and that dinosaurs are therefore still alive today. Similarly, placoderms, a group of extinct armored fishes, long held little or no interest to evolutionary biologists. However, discoveries from China are changing that by showing how important placoderms are to understanding the early assembly of the vertebrate body plan. On page 334 of this issue, Zhu et al. (1) report the discovery of a placoderm from Qujing in Yunnan, China, that fills a big gap in our understanding of how vertebrate jaws evolved.