In principle, they breed only with others on their own island, speeding up evolutionary divergence, a process also observed in Galápagos finches. Since Galápagos tortoises don’t like swimming, they spread to other islands in the archipelago only by rare accident. The initial migration landed on one of the archipelago’s oldest islands, either Española or San Cristóbal. Two to three million years ago, a storm swept a tiny population of mainland giant tortoises (or possibly just one pregnant female) across from South America. Either way, they are all descended from a single ancestor. Some consider the dozen subspecies of the Galápagos tortoise distinct enough to label them separate species. They diverged from their closest living relative, the much smaller Chaco tortoise from Paraguay and Argentina, between 6 and 12 million years ago. The giant tortoises of the Galápagos are not related to the giant tortoises still extant on the Seychelles. Both are distinct from the other 11 surviving subspecies.Ĭollected in 2019, Fern resurrected an entire subspecies of giant ghost tortoises just by being alive. In other words, she belongs to Chelonoidis niger phantasticus, the same subspecies as a specimen collected on the island in 1906. However, in May 2022, genome sequencing finally established that Fern is indeed a native of Fernandina. Tortoise scat and other circumstantial evidence Its lava flows don’t just impede human exploration and settlement they had also cast doubt on the survival of a separate subspecies of the Galápagos tortoise on the island. Dominated by an active volcano, Fernandina is said to be the largest pristine island on Earth. The fifty-something female is the first of her kind to be found in over a century, living proof that her subspecies is not extinct.įernanda, or “Fern” for short, was collected in February 2019 on Fernandina Island, the third largest of the 21 islands in the Galápagos archipelago, off the coast of Ecuador. ( Credit: Aaron Logan, CC BY 2.0)Ī rock star among animal species, the Galápagos giant tortoise ( Chelonoidis niger) has produced a power trio of global celebrities: Lonesome George, the last of his kind Diego the Playboy Tortoise, the first of many of his kind and Harriet - formerly Harry - collected by Darwin himself, who died at 176, the oldest known specimen of its kind. Iguanas sunning on Fernandina Island, home to a wide range of endemic species, including a recently rediscovered subspecies of the Galápagos giant tortoise.
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