A 200-year-old South African cave painting made by the region’s first inhabitants, the San people, appears to depict an animal that has been extinct for over 200 million years. A long-bodied animal with downward-turned tusks, the warm-blooded, lizard-like creature called a dicynodont (two-toothed dog) roamed the area before the first dinosaur appeared and died off at the end of the Triassic. If the artwork from the cave’s Horned Serpent panel at La Belle France (Free State Province, South Africa) is of this extinct species, its creation would predate the first known scientific classification of a dicynodont by at least a...