Researchers studying the genes of a single population of giant tortoises on an island in the Galapagos have discovered that they are actually two separate species.

The first species (Chelonoidis porter), living on the Western side of Santa Cruz Island, is comprised of some 2,000 individuals and protected within a national park. The second, newly discovered species (Chelonoidis donfaustoi), resides on the eastern side and features a population just under 250 individuals. Despite living only a few miles away from each other, the two populations are genetically completely different.

Biologists, writing in the journal Plos One, say the new species designation will go a long way toward helping this small population of giant tortoises survive and grow.

"This is a small and isolated group of tortoises that never attracted much attention from biologists previously," James Gibbs, a conservation biologist at the State University of New York, told the Business Standard. "But we now know that they are as distinct as any species of tortoise in the archipelago. Their discovery and formal description will help these tortoises receive the scientific and management attention they need to fully recover."

Once found all over the world, giant tortoise populations are now confined to specific island regions such as the Galapagos, the Seychelles and Mascarene Islands. Devastated by hunting and a loss of habitat, their populations have since rebounded thanks to widespread conservation efforts.

"The global population was down to just 15 tortoises by the 1960s. Now there are some 1,000 tortoises breeding on their own," Gibbs said in a paper published last year. "The population is secure. It's a rare example of how biologists and managers can collaborate to recover a species from the brink of extinction."