Stunning new scan data of an enigmatic fish from the Early Devonian of Australia, Ligulalepis, is identified as a stem osteichthyan, specifically, as the sister taxon to the 'psarolepids' plus crown osteichthyans.

Homology of vertebrate skull structures should be based on evolutionary continuity and an appreciation of germ layer origins and inductive signaling in the embryonic head.

The ancestor of all known jawed vertebrates possessed a maxilla and premaxilla and was similar in morphology to the 'maxillate placoderms' from China.