Tiny 436-Million-Year-Old Fossil Recasts the Origin of Bony Vertebrates
A 436-million-year-old bony fish fossil, Eosteus chongqingensis, from China’s Chongqing Lagerstätte, is the oldest near-complete articulated osteichthyan and shows bony-fish traits emerged earlier than thought; a second find, Megamastax amblyodus from ~423 million years ago, reveals a large Silurian predator with early bony-fish dentition, helping place these early fishes on the osteichthyan stem and filling gaps in pre-Devonian vertebrate evolution.