Explained: Chelonoidis phantasticus, a giant tortoise species discovered after a century

When Fernanda was discovered in 2019, many ecologists doubted that she was actually a native phantasticus tortoise. She differed in appearance from the male historical specimen, although scientists speculated that her stunted growth may have distorted her features, Princeton University said in a press release.

Although Fernanda was found on Fernandina Island itself, and although tortoises can’t swim from one island to another, they can be carried from one Galápagos island to another during major storms. There are also historical records of seafarers moving the tortoises between islands.

“Like many people, my initial suspicion was that this was not a native tortoise of Fernandina Island,” Princeton University quoted researcher Stephen Gaughran, a postdoctoral research fellow in ecology and evolutionary biology at Princeton.

To determine Fernanda’s species definitively, Gaughran sequenced her complete genome and compared it to the genome he was able to recover from the specimen collected in 1906. He also compared those two genomes to samples from the other 13 species of Galápagos tortoises — 12 living, one extinct. He showed that the two known Fernandina tortoises are indeed members of the same species.

“We saw — honestly, to my surprise — that Fernanda was very similar to the one that they found on that island more than 100 years ago, and both of those were very different from all of the other islands’ tortoises,” Gaughran was quoted as saying.

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