“Fantastic giant tortoises” thought to be extinct still live, scientists know

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Scientists were shocked in 2019 when a unique female turtle was discovered on the volcanic island of Fernandina in the western Galápagos archipelago.

This is because the last time a Chelonoidis fantasticusor “fantastic giant tortoise”, was found in 1906.

“All we knew about this species said it was extinct,” said Stephen Gaughran, a postdoctoral researcher in ecology and evolutionary biology at Princeton University The guard.

“It was almost too good to be true that there was a turtle living on Fernandina,” Evelyn Jensen, lecturer in molecular ecology at Newcastle University in the UK, told CNN. “We were all so excited.”

When the turtle, named “Fernanda” after the island where it was found, was compared to the deceased male specimen kept in a California Academy of Sciences museum collection, scientists thought they had a problem. That’s because Fernanda doesn’t look like the male.

But by sequencing the genomes of both Fernanda and the museum specimen, and comparing them to the other 13 species of Galápagos giant tortoises, Gaughran was able to determine that the two known Fernandina tortoises are indeed members of the same species.

Gaughran is co-author of an article in the current issue of communication biology Confirmation of the continued existence of Fernanda’s species.

“Like many people, my initial suspicion was that this was not a native Fernandina Island turtle,” Gaughran said in a statement. “We saw – frankly, to my surprise – that Fernanda was very similar to the tortoise they found on this island more than 100 years ago, and both were very different from any tortoises on the other islands.”

How Turtles Arrived in the Galápagos Islands

Turtles are not native to the Galápagos Islands, nor can they swim. But they swim.

Scientists believe that sometime between 2 and 3 million years ago, a violent storm carried giant tortoises from South America to the Galápagos Islands. The turtles then bred with each other on the islands they landed on, leading to rapid evolution. This crossing resulted in the 14 species.

The biggest difference in these turtles is their shell shape. Some of the tortoises have a convex upper shell. Others, like the male Fernandina, have a saddleback-style carapace that arches over the turtle’s head and neck.

“The arc in the shell gives these turtles a much greater range of motion with their necks, allowing them to reach higher to eat plants off the ground, so it may have evolved to access more food,” said Jensen, who wrote it is co-author of the article in communication biologyaccording to CNN.

Why Fernanda is different

The male turtle, found in 1906, had a shell with an extreme saddleback shape and prominent flaring at the edges, which is why it was named “Phantasticus,” Jensen continued.

On the other hand, Fernanda, thought to be over 50 years old, has a smaller, smoother carapace than the 1906 male. However, she is also smaller, which the scientists hypothesize could be due to the limited vegetation on the island. Their stunted growth may also have contributed to the distorted shape of their carapace.

Are there others like Fernanda?

The question that worries the scientists is: Are there other turtles like Fernanda on Fernandina Island?

That’s hard to answer.

The island remains largely unexplored, with extensive lava fields blocking access to its interior. Alleged turtle droppings, however, were not spotted by planes until 2014.

“Fernandina is the highest of the Galápagos Islands, is geologically young and consists mostly of a huge pile of jagged brown blocks of lava,” explained Peter Grant, professor emeritus of zoology for the Princeton class of 1877 and professor emeritus of ecology and evolutionary biology at Princeton University. “At lower elevations, vegetation occurs in island-like clumps in a sea of ​​recently solidified lava. Fernanda was found in one of these, and there is evidence that some relatives may exist in others.”

Fernanda now resides at the Galapagos National Park’s Fausto Llerena Giant Tortoise Breeding Center, a rescue and breeding facility. If more tortoises like Fernanda are found, conservationists could start a captive breeding program to keep the species alive.

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