Abstract

The origin of the jawed vertebrates remains one of the persistent mysteries in vertebrate evolution. Jaws, teeth, and paired fins are widely regarded as vertebrate ‘key innovations’, but their origins remain poorly documented in the fossil record. We know that jawed vertebrates originated more than 420 million years ago, but no fossil intermediates between jawless and jawless vertebrates have ever been confidently identified. Despite remarkable and well-publicised discoveries in recent years, almost none of these have been able to firmly bridge the gap between jawless vertebrate anatomy and modern jawed vertebrates. In this talk, I will present a refreshed view of jawed vertebrate origins and the origins of paired fins, drawing on new fossil data and new interpretations. Debates about the origin of jaws and paired fins have thus been dominated by compelling but speculative theories based on pre-Darwinian ‘idealistic morphology’. By returning to the fundamentals of comparative anatomy, employing high-resolution computed tomography, and integrating biomechanical and comparative developmental knowledge, I will help close the morphological gap between early jawed vertebrates and their nearest jawless relatives. These results will provide surprising new evidence on one of the enduring mysteries of vertebrate evolution: the evolution of a distinct head and shoulder and how this helps us resolve the simultaneous origins of jaws and fins.