/ 17 March 2022

New giant tortoise species found on Galápagos after DNA study

Wild Galapagos Giant Tortoise (geochelone Elephantopus), Santa Cruz Island, Galapagos Islands, Unesco World Heritge Site, Ecuador, South America
Diversity: Giant tortoises on Galápagos Islands of Ecuador are under scientific scrutiny since scientists found they may have misnamed one of them. (Michael Nolan/Robert Harding Premium/AFP)

A new species of giant tortoise has been discovered in the Galápagos after DNA testing found animals living on one island had not yet been recorded, Ecuador’s environment ministry said.

Researchers compared the genetic material of tortoises living on San Cristóbal with bones and shells collected in 1906 from a cave in the island’s highlands and found them to be different. 

The 20th-century explorers never reached the lowlands, where the animals live today and, as a result, almost 8 000 tortoises correspond to a different lineage to what was previously thought.

“The species of giant tortoise that inhabits San Cristóbal Island, until now known scientifically as Chelonoidis chathamensis, genetically matches a different species,” the ministry said last week.

The Galápagos Conservancy said in a newsletter that the Chelonoidis chathamensis species is “almost certainly extinct”.

Located in the Pacific about 1 000km off the coast of Ecuador, the Galápagos Islands are a protected wildlife area and home to unique species of flora and fauna. 

The Galapagos, a World Heritage Site, owe their name to the giant tortoises.

The archipelago was made famous by British geologist and naturalist Charles Darwin’s observations on evolution there.

There were originally 15 species of giant tortoise on the islands, three of which became extinct centuries ago, according to the Galápagos National Park.

Millions of years ago San Cristóbal was perhaps bisected by the sea and each part had its own species of chelonian. 

But when the water level dropped, the two islands merged, and so did their turtles.

In 2019, a specimen of Chelonoidis phantastica was found on Fernandina Island more than 100 years after the species was considered extinct.

The study by researchers from Newcastle University in Britain, Yale University in the United States, the American nongovernmental organisation Galápagos Conservancy and other institutions was published in the scientific journal Heredity.

They will continue to recover more DNA from the bones and shells to determine whether the tortoises living on San Cristóbal should be given a new name. — AFP