Geochelone robusta (Adams 1877) : an insular giant?

Abstract

Giant size is probably plesiomorphic among insular giant tortoises, that is they are probably descended from a giant tortoise ancestor that reached the island overland or by making a sea-crossing. Geochelone robusta is unlikely to have evolved giant size in Malta as most of the known fossil European species of Geochelone were giant tortoises and the ancestor of G. robusta is thus likely to have been a giant tortoise. This species was a palaeotropical relict, that is a survival from the time, earlier on during the Tertiary, when the climate of the region was warmer. Geochelone robusta survh:ed the cold stages of the pleistocene and Quaternary because the climate in Malta during the very coldest stages did not include prolonged, severe frosts.