The giant Galápagos tortoise is known around the globe for inspiring Charles Darwin’s theory of evolution. Now, a new piece of the puzzle has emerged: scientists have identified a previously unknown species of the shelled island-dwelling animals. The new species represents a line of evolutionary history never before studied, and genetic researchers are chomping at the bit to unravel the mystery behind this surprising discovery.
This marks the first time in over a century that a new species of tortoise has been identified in the Pacific archipelago. The new species – named Chelonoidis donfaustoi – lives in the Cerro Fatal region of Santa Cruz island, near the center of the archipelago, and is nick named “Don Fausto” after a 75-year-old ranger who recently passed away. The curious thing is that these tortoises are less genetically similar to the main colony living on the island. Although those two species are capable of interbreeding (not all tortoises can do that, apparently), it hasn’t happened very often, according to the team who has been studying the island tortoises. In fact, the newly identified species is more closely related to tortoises living on other islands.
“Now the genetics has put some real evidence that says the simple explanations don’t hold, that some of the islands have tortoises that arrived at different times from different islands,” said Oliver Ryder, director of genetics at the San Diego Zoo’s Institute for Conservation Research, who was not involved in the new discovery. “The recognition of this separate evolutionary history I think will be very important.”
In general, this discovery marks the 14th confirmed species of Galápagos tortoise. In addition to existing species, that figure includes two extinct ones: Santa Fe, which disappeared more than 150 years ago, and Pinta, whose last survivor died just three years ago. The discovery of the new species was detailed in a report published this week in the journal PLOS One.
Images via Washington Tapia and N Poulakakis, et al.