A species of giant tortoise that was thought to have been extinct for greater than century has been discovered alive and well on a tropical island.
The Fernandina Island Galápagos giant tortoise (Chelonoidis phantasticus, or ‘improbable giant tortoise’) was once known only from a single specimen collected during a scientific expedition in 1906.
This was until a female giant tortoise, named Fernanda, was found roaming Fernandina Island in 2019.
Scientists from Princeton University and and Yale University extracted Fernanda’s DNA, together with that of the 116-year-old male specimen.
In a paper published today in Communications Biology, the researchers reveal that the 2 are Chelonoidis phantasticus tortoises, and are genetically distinct from all other species of Galápagos giant tortoise.
Fernanda, the one known live Fernandina Island Galápagos giant tortoise, was present in a clump of vegetation in a sea of recently congealed lava in February 2019
The Fernandina Island Galápagos giant tortoise was once known only from a single specimen collected during a scientific expedition in 1906, before Fernanda was discovered
Peter Grant, Professor of Zoology at Princeton University and expert on the Galápagos, said: ‘For a few years it was thought that the unique specimen collected in 1906 had been transplanted to the island, because it was the one one in every of its kind,
‘It now appears to be one in every of a only a few that were alive a century ago.’
Fernandina Island is an energetic volcano on the western side of the Galapagos Islands, which Charles Darwin visited in 1835, inspiring his theory of evolution.
Minor evidence of living Fernandina Island tortoises was found after the 1906 discovery, for instance 18 scats were seen on the western slopes of the island in 1964.
Other scats and a possible visual remark from an aircraft were reported within the early 2000’s, and one other possible tortoise scat was seen in 2014.
Fernanda was present in a clump of vegetation in a sea of recently congealed lava in February 2019.
Scientists estimate that she is well over 50 years old, but she is small, possibly since the limited vegetation stunted her growth.
When Fernanda was first discovered, many ecologists doubted she was actually a native phantasticus tortoise.
She doesn’t exhibit the unique flaring on the periphery of her saddleback shell that could possibly be seen on the 1906 specimen collected by explorer Rollo Beck.
Saddlebacking is exclusive to Galápagos tortoises, and the phantasticus tortoise shows it more prominently than the opposite species.
Fernanda could have also been transported from elsewhere as, while they can not swim, tortoise’s may be floated between islands during a hurricane or storm, or could possibly be carried by seafarers.
Stephen Gaughran, postdoctoral research fellow in ecology and evolutionary biology at Princeton, said: ‘Like many individuals, my initial suspicion was that this was not a native tortoise of Fernandina Island.’
A male specimen of the Fernandina Island giant tortoise (pictured) was collected in 1906 by explorer Rollo Beck, and for years was the one evidence of the species’ existence
Scientists estimate that Fernanda is well over 50 years old, but she is small, possibly since the limited vegetation available on the volcanic Isla Fernandina stunted her growth
Fernandina Island is an energetic volcano on the western side of the Galapagos Islands, which Charles Darwin visited in 1835, inspiring his theory of evolution
Gaughran sequenced Fernanda’s genome from a blood sample, and compared it to that of the museum specimen in addition to the opposite 13 species of Galápagos giant tortoises with a purpose to rule them out.
Gaughran added: ‘We saw – truthfully, to my surprise – that Fernanda was very much like the one which they found on that island greater than 100 years ago, and each of those were very different from the entire other islands’ tortoises.’
Senior writer and research scientist Adalgisa Caccone from Yale University said: ‘The finding of 1 alive specimen gives hope and in addition opens up latest questions, as many mysteries still remain.
‘Are there more tortoises on Fernandina that may be brought back into captivity to begin a breeding program?
‘How did tortoises colonise Fernandina, and what’s their evolutionary relationship to the opposite giant Galápagos tortoises?
‘This also shows the importance of using museum collections to know the past.’
While the island has remained largely unexplored resulting from extensive lava fields blocking access to its interior, more scats and a few tracks of a minimum of two more tortoises has been found during recent expeditions.
Genetic distances between Fernanda and one another tortoise, between individuals of the identical species, and between individuals of various species. Fernanda and the archive male specimen are in magenta. The genetic distance between the 2 tortoises from Fernandina is smaller than the space between Fernanda and any of the opposite tortoises sequenced
Evolutionary biologist Peter Grant says that Fernanda’s genome suggests that Chelonoidis phantasticus is the product of a combination of various Galápagos species.
He said: ‘The closest relatives will not be on the closest very large island, Isabela, but on one other, Española, distant on the opposite side of Isabela.
‘The query of how the ancestors reached Fernandina is left hanging.’
Fernanda is now on the Galápagos National Park Tortoise Center, a rescue and breeding facility on Santa Cruz Island, where experts are seeing what they will do to maintain her species alive, including trying to search out a male mate.
Grant added: ‘The invention informs us about rare species that will persist in isolated places for a very long time,
‘This information is vital for conservation.
‘It spurs biologists to go looking harder for the previous few individuals of a population to bring them back from the brink of extinction.’
For now, Fernanda is in an identical position to Lonesome George, who was famed for being the last of the Pinta Island Galapagos giant tortoises.
Lonesome George lived out his final many years of life in captivity but never bred and his species went extinct in 2012 following his death from old age.
HISTORY OF GIANT TORTOISES ON THE GALÁPAGOS ISLANDS
Two or three million years ago, a storm carried a number of giant tortoises from the South American mainland westwards
Because they don’t swim, the tortoises bred only with others on their very own islands, leading to rapid evolution
Today, there are 14 different species of giant Galápagos tortoises, all descended from a single ancestor
Tortoises from the easternmost islands show rounder, domed shells, and the westernmost island, Fernandina, showing essentially the most dramatic saddlebacking
Saddleback shells are raised and have flared edges, and are combined by long limbs and neck on the tortoise
The domed tortoises live in additional humid, higher elevation ecosystems, while their saddlebacked cousins inhabit drier, lower elevation environments
All 14 species are listed on the IUCN Red List as either vulnerable, endangered, critically endangered or extinct
It is because the tortoise populations were decimated by European seafarers who hunted them for food
They found that they may keep tortoises alive on their ships with minimal effort, because the reptiles could survive with little food or water
Because of this of the very long time between tortoise generations, the populations will not be in a position to recuperate quickly from such depletion
There are 13 different species of Galápagos giant tortoise within the cluster of 21 islands