Galápagos tortoise
At the end of the 19th century, Georg Baur and Walter Rothschild recognised five more populations of Galápagos tortoise. In 1905–06, an expedition by the California Academy of Sciences, with Joseph R. Slevin in charge of reptiles, collected specimens which were studied by Academy herpetologist John Van Denburgh. He identified four additional populations, and proposed the existence of 15 species. Van Denburgh's list still guides the taxonomy of the Galápagos tortoise, though now 10 populations are thought to have existed.