Blogs / 80beats

On the slopes of the Wolf volcano at the northern tip of one of the Galapagos Islands prowls a pink iguana, which until recently had entirely escaped the notice of the island’s visitors–including the eagle-eyed Charles Darwin. But now researchers have spotted the rosy reptile and declared it a new species, which diverged from the Galapagos’s other land iguana species about 5.7 million years ago. Says lead researcher Gabriele Gentile: “What’s surprising is that a new species of megafauna, like a large lizard, may still be [found] in a well-studied archipelago” [National Geographic News].

The creature was first noticed by park rangers on the island of Isabela in 1986, but researchers only began to study the animal in the last few years. A genetic analysis revealed that the pink iguana was quite distinct from the two known land iguana species, but the date of their genetic divergence poses a puzzle. “At 5.7 million years ago, all of the western islands of the archipelago did not exist,” said Gabriele Gentile…. “That’s a conundrum, because it’s now only inhabiting one part of Isabela that formed less than half a million years ago” [BBC News]. In fact, even the oldest parts of the current archipelago may be less than five million years old, researchers say. One possible explanation is that volcanoes that are now underwater may have been above the waves millions of years ago, allowing some marine iguanas to clamber onto those shores and begin evolving.

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Poor Lonesome George: Although he may have found a mate, researchers say he is still being denied the joys of fatherhood. George is thought to be the last representative of a tortoise subspecies from the Galapagos Island of Pinta, and researchers rejoiced this summer when he appeared to father a batch of eggs. But earlier this week a spokesperson for the Galapagos National Park announced that 80 percent of the eggs do not appear to be viable.

The excitement began this summer when two female tortoises exhibited surprising behavior. The females, who have shared George’s enclosure at the Charles Darwin Research Station on the central island of Santa Cruz for almost 20 years, are of a different but closely related species. After decades of reproductive reticence, they stunned scientists during the summer by building nests and filling them with eggs for the first time [Nature News]. Researchers quickly removed the 16 eggs from the nests and installed them in an artificial incubator, although three of those eggs were thought to have already deteriorated.

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Researchers may be able to recreate a species of giant tortoise that went extinct from the Galapagos Islands with a program of careful breeding. The new possibility hinges on the discovery that a species of giant tortoise living on the biggest island, Isabela, is very similar genetically to the extinct species, Geochelone elephantopus, which vanished from the island Floreana over a hundred years ago.

By mating Isabela tortoises that are most genetically similar to G. elephantopus, selecting the offspring that are most similar and mating those, through successive generations the species’ genetic makeup may be largely restored [The New York Times]. Says lead researcher Gisella Caccone: “We might need three or four generations to do this…. But in theory it could be done, and I think it’s pretty exciting to bring back from the dead a genome that we thought was gone” [BBC News].

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