Darwin missed it. So did everyone else. The iguana with the pink stripes was thought to be just a stained variation of the other land iguanas.
But researchers have concluded that the pink iguana is not only a different species than the other two known iguana species in the Galápagos, it is actually older.
The article was published January 5, 2009 in the Proceedings of the National Academy of Sciences. The abstract is included below.
Found only around Isabela Island's Wolf Volcano, an area not visited by Darwin, the iguana was first noted in 1986 by researchers, but was mostly ignored.
Not until 2001 was it studied, when researchers from the University of Rome Tor Vergata and from the Galápagos National Park began to investigate whether the lizards were a different species or were an adaptation from the Galápagos' two known land iguanas: the Conolophus subcristatus and Conolophus pallidus.
Genetic testing of 36 iguanas revealed a primary split between the rosada and all other land iguanas in the Galápagos, estimated to have occurred about 5.7 million years ago. This places the divergence prior to the formation of Volcan Wolf (the rosada's only home), and other islands in the archipelago.
The pink iguana population size, eating and reproductive habits are still unknown, and no young animals have been yet discovered.
The iguana may already be in danger of extinction under threats by feral animals. Further research will determine what resources are needed to guarantee the lizards' survival.
The article, An overlooked pink species of land iguana in the Galápagos by Gabriele Gentilea, Anna Fabiania, Cruz Marquez, Howard L. Snell, Heidi M. Snell, Washington Tapiad, and Valerio Sbordonia, is available on the Proceedings of the National Academy of Sciences website: http://www.pnas.org/
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The "iguana rosada" on Volcan Wolf, the latest surprise the Galápagos islands have offered up to the world. (PNAS)
A Galápagos National Park image of the newly classified, and still unnamed, pink iguanas.
"Despite the attention given to them, the Galápagos have not yet finished offering evolutionary novelties. When Darwin visited the Galápagos, he observed both marine (Amblyrhynchus) and land (Conolophus) iguanas but did not encounter a rare pink black-striped land iguana (herein referred to as “rosada,” meaning “pink” in Spanish), which, surprisingly, remained unseen until 1986. Here, we show that substantial genetic isolation exists between the rosada and syntopic yellow forms and that the rosada is basal to extant taxonomically recognized Galápagos land iguanas. The rosada, whose present distribution is a conundrum, is a relict lineage whose origin dates back to a period when at least some of the present-day islands had not yet formed. So far, this species is the only evidence of ancient diversification along the Galápagos land iguana lineage and documents one of the oldest events of divergence ever recorded in the Galápagos. Conservation efforts are needed to prevent this form, identified by us as a good species, from extinction."
Read the article online: http://www.pnas.org/