From New Scientist:
Darwin missed ‘earliest’ Galapagos species
* 19:58 05 January 2009 by Rowan Hooper
It is one of the most studied parts of the world, and played a major part in shaping Darwin’s thinking about the origin of species – yet the Galapagos Islands continue to give more to our understanding of biology.
It was finches that led Darwin to understand that species could change with environmental pressures, and now genetic analysis has revealed that a long-overlooked pink iguana is a species in its own right. The analysis also suggests the pink iguana is one of the earliest examples of species diversification on the islands.
Galapagos land iguanas belong to the genus Conolophus, of which there are currently three recognised species. Remarkably, given their colour, pink iguanas were apparently not seen until they were noticed by park rangers in 1986. They are sometimes known as “rosada” iguanas, from the Spanish for pink.
Gabriele Gentile of Tor Vergata University of Rome, Italy, and colleagues took blood samples of rosada iguanas and the other two species in order to test their relatedness.
Genetic analysis shows that the rosada iguana originated in the Galapagos more than five million years ago, and diverged from the other land iguana populations even as the archipelago was still forming.
The pink form, says Gentile, should be considered a third species, and is evolutionarily older than the other two species.
And though it has only recently been discovered, Gentile says conservation measures are needed to prevent the pink iguana from going extinct.
“Available data suggest that the population size of the pink iguana is very small,” he says. Feral cats in the region could be eating eggs and young iguanas, Gentile speculates. Direct hunting by humans is also blamed.
Update March 2011: here.
Conservation of Galápagos land iguanas: genetic monitoring & predictions of a long-term program on the island Santa Cruz: here.
Raft or bridge: How did iguanas reach tiny Pacific islands? Here.
The Lesser Antillean Iguana, Iguana delicatissima, is listed as ‘Endangered’ on the IUCN Red List of Threatened SpeciesTM. Once common throughout most of the northern Lesser Antilles of the Caribbean, this impressive lizard has been extirpated from several islands and is declining on most others: here.
January 2012. For the first time in eleven years Durrell Wildlife Conservation Trust’s rare Lesser Antillean iguanas have successfully bred, producing two young hatchlings: here.
Lutz’s tree iguana (Liolaemus lutzae): here.