A view of the skeletal structure of the pectoral fin

FILE PHOTO: A view of the skeletal structure of the pectoral fin of the extinct fish Elpistostege watsoni, which lived about 380 million years ago, and that of a person, showing the evolutionary origin of the bones that now make up the human hand is seen in this illustration released to Reuters on March 18, 2020. John Long/Handout via REUTERS