Galapagos tortoise species rediscovered?

Skeleton of Floreana island tortoise

The Galapagos Islands are a group famous for having different species on each island due to evolutionary processes, including several species of Galapagos tortoise. Four of the fifteen (or ten or eleven) known species (or subspecies) have gone extinct.

The  species native to the island of Floreana was believed to be extinct for 160 years, since the early 1840s. Now, scientists have found evidence that a remnant population may have survived in an isolated part of the larger island of Isabela. The tortoise native to Floreana was Chelonoidis elophantopus,* recognized by the saddleback shape of its shell. The tortoise of Isabela is Chelonoidis becki, with a dome-shaped shell.

Three years ago, a team from Yale University found tortoises around the Wolf Volcano on Isabela that appeared to be hybrids, giving them the hope that they could breed back to a tortoise that looked like the extinct species (Extinct tortoise ‘could live again’). However, further exploration has turned up more than eighty that seem to have a C. elophantopus as one of their parents—and some of them are only fifteen years old. That suggests that a few purebred elophantopus tortoises survive. The scientists’ calculations suggest that there are about 38 of them, including both males and females. See “‘Extinct’ Galapagos tortoise may still exist.”

The tortoises may have been moved by whaling ships that picked up the tortoises on Floreana, then stopped at the north end of Isabela and lost a few tortoises in their stopover. It’s hard to see the tortoises in the brush growing over the rugged and arid country. The group took samples of 1,600 tortoises to find their 84 hybrids–half of one percent of the population. They will now discuss with the government whether to keep on surveying and whether they can set up a breeding program to recreate the tortoise of Floreana.

What’s the difference between a turtle and a tortoise? Ha! What I grew up calling a “turtle” is more properly called a “terrapin.” And Galapagos is spelled “Galápagos.”

*Now renamed Chelonoidis nigra nigra

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