Jan. 2012 - A Galapagos Islands tortoise species known as Chelonoidis elephantopus, thought to be hunted to extinction over 150 years ago, may still be living in the Islands according to a recent Yale University study[1].
 
Yale researchers from the Department of Ecology and Evolutionary Biology discovered the genetic signature of the C. elephantopus tortoise among blood samples taken from tortoises on Isabela Island, indicating hybridization between species. 
 
Over 1600 tortoises were sampled[2] (approximately 20% of Isabela’s tortoise population), with 84 showing the genetic markers in question.  Of those 84 individuals, 30 were 15 years of age or younger.   As tortoises can live to well over 100 years of age, researchers suspect that there are very likely purebred parents among the older population of tortoises on the island.  Calculations based on genetic markers[3] suggest there may be as many as 30 purebred tortoises on Isabela, although none have yet been identified.
 
If purebreds are found, the goal will be to develop a captive breeding program to restore a population of C. elephantopus to their original home on Floreana Island, 52 kilometers to the south east of Isabela Island.
 
The Chelonoidis elephantopus has a unique saddle shaped shell, one that Charles Darwin studied[4] and noted in his theory of natural selection.