‘Extinct’ giant tortoise was relaxing on an island

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A presumed extinct giant tortoise from the Galapagos Islands was found alive in 2019, and a new DNA study confirms the female tortoise is the same species as an animal collected more than a century ago. “Fernanda”, as they call her, is the only living turtle on Fernandina Island (Chelonoidis phantastica) known and only the second member of the species ever recorded.

The Galapagos archipelago, birthplace and testing ground for Darwin’s theory of natural selection, is dazzled by giant tortoises, some of which have become extinct since their discovery. The most famous of these animals is undoubtedly Lonesome George, the last (or ‘final’) tortoise on Isla Pinta, who was around 100 years old when he died in 2012, marking the extinction of that species.

Fernanda (‘Fern’ for short) represented a shocking discovery when researchers discovered her in 2019 on the volcanic island of Fernandina. Only now has a team of researchers extracted DNA from the tortoise and confirmed that it is, in fact, a tortoise from Fernandina Island. Your study is publish in Current Biology.

“Because tortoises can occasionally move between islands, we were not sure if Fernanda was in fact a native tortoise on Fernandina Island or if it had migrated to Fernandina from a different island in the Galápagos,” said Stephen Gaughran, a zoologist with the Princeton University and co-author of the recent paper, in an email to Gizmodo. Although the turtles cannot swim, they do float (despite their weight) and can be transported to adjacent islands during severe storms. Humans have also moved turtles between islands.

“To test this, we took a blood sample from Fernanda and sequenced her genome,” Gaughran added. “We then compared her genome to the genome of a museum specimen of a Fernandina tortoise collected over 100 years ago, and to the genomes of all other Galapagos giant tortoise species.”

The team’s analysis revealed that Fernanda was in fact the same species as the holotype specimen discovered in 1906, which until now was the only known tortoise from Fernandina Island. The two tortoises were genetically distinct from the 12 extant Galapagos tortoises, as well as from the extinct Pinta Island tortoise.

Image for article titled 'Extinct' Giant Tortoise  he was relaxing on an island

Interestingly, genetic analysis revealed that tortoises from Fernandina Island were most closely related to tortoises from Española Island, one of the furthest islands from Fernandina. It is unknown how exactly Fernanda’s ancestors came to vwestern volcano.

Fernanda’s existence raises hope that other tortoises on Fernandina Island are still alive. Fern is over 50 years old, but small for her size, perhaps due to the scant vegetation available on Fernandina. It has been relocated to Galapagos National Park Turtle Centerwhere experts can take care of Fern instead of having to fend for herself on the inhospitable island.

“At lower elevations, vegetation occurs in island-like clusters in a sea of ​​recently frozen lava,” said Peter Grant, an evolutionary biologist at Princeton University who is not affiliated with the recent paper but has worked extensively on the Galapagos. , in a statement from the university. “Fernanda was found in one of these, and there is evidence that some relatives may exist in others.”

This is not the first time that a species of Galapagos tortoise has been presumed extinct, only for evidence to the contrary to appear. Ten years ago, the same year Lonesome George died, a team of researchers argued than the tortoise on Floreana Island (Chelonoidis elephantopus) was probably still alive, based on genetic fingerprints of the species in hybrid turtles.

Of course, we can never prove that an animal is really extinct; it is more of a very careful guess made after numerous searches yielded no results. But several of the article’s co-authors are planning expeditions to search Fernandina for Fernanda’s relatives. Even a male tortoise would make the recovery of the species infinitely more likely, barring biological miracles.