Age and Dietary Differences of Recently Extinct Indian Ocean Tortoises (Geochelone s. lat.) Revealed by Carbon Isotope Analysis

摘要: All but one of the seven or eight species giant tortoise (Geochelone) in southwest Indian Ocean became extinct by mid-nineteenth century, leaving many aspects their history and biology unknown. Radiocarbon dating fossil remains indicates that population G. gigantea on small island Assumption was a natural one, predating European activity area. It also confirms two known from Mauritius, inepta triserrata, were indeed synchronous this true pair found Madagascar, grandidieri abrupta. Survival both latter well into first millennium A.D. is demonstrated, suggesting they still present when human colonists arrived perhaps exterminated them. Stable carbon isotope ratios indicate that, apparently unlike other tortoises, ate high proportion plants with C$_{4}$ metabolism. This may have reduced potential competition sympatric