Jawed dominance a longtime coming

摘要

The first jawed vertebrates, or gnathostomes, were vastly outnumbered by their jaw-less relatives. Today, more than 99% of vertebrates have jaws. It is therefore tempting to conclude that the evolution of jaws was key to the rise of the vertebrates. But matters might have been more complicated, according to a quantitative biomechanical analysis of early gnathostome mandibles. Anderson et al. show that early jawed vertebrates had many jaw designs, but ended up with a few tried-and-tested, conservative forms long before the jaw-less vertebrates went into decline.