A recent study found that the Fiji iguanas sailed over 8000 kilometers from the western coast of North America millions of years ago.
They did so by settling in the isolated group of islands in the South Pacific. This species is closely related to the one from the North American desert, as confirmed.
This proves the longest known transoceanic dispersion of any terrestrial animal.
Fiji iguanas and a historical navigation
A new analysis by biologists from the University of California, Berkeley, and the University of San Francisco (USF) suggests that about 34 million years ago, Fiji iguanas traveled 8000 kilometers.
They did so from the western coast of North America to reach the islands.
Dispersion over water is the main way newly formed islands become populated with plants and animals, including humans. This often leads to the evolution of new species and completely new ecosystems.
Fiji iguanas. (Photo: Argentinat).[/caption>
The new analysis, published in the journal Proceedings of the National Academy of Sciences, suggests that the arrival of the ancestors of the Fiji iguanas coincided with the formation of these volcanic islands.
The estimated date of the arrival, according to them, is based on the time of the genetic divergence of the Fiji iguanas, Brachylophus, from their closest relatives. That is, the North American desert iguanas, Dipsosaurus.
The previous idea was based on the possibility that they could descend from an older lineage, more widespread across the Pacific. But it has since become extinct, leaving Brachylophus as the only iguanids in the western Pacific Ocean.
But the new analysis refutes all previous theories. “We found that the Fiji iguanas are closely related to the North American desert iguanas, something that had not been previously determined,” the study indicates.
The common origin
“And that the lineage of the Fiji iguanas separated from their sister lineage relatively recently, much closer to 30 million years ago, either later or approximately at the same time as volcanic activity that could have produced land,” said lead author Simon Scarpetta in a statement.
Scarpetta is a herpetologist and paleontologist, a former postdoctoral fellow at UC Berkeley and current adjunct professor in the Department of Environmental Sciences at USF.
How these animals arrived
The impressive theory about the journey of the iguanas. (Photo: Argentinat).[/caption>
“That they reached Fiji directly from North America seems crazy,” co-author Jimmy McGuire stated, a professor of integrative biology at UC Berkeley and curator of herpetology at the Museum of Vertebrate Zoology.
The collected and analyzed data suggest that as soon as the land where Fiji is now located appeared, these iguanas could have colonized it. Regardless of the exact timing of the dispersion, the event itself was “spectacular,” according to the authors.
What Fiji iguanas look like
The species was discovered by chance during the filming of the movie The Blue Lagoon in 1981. It happened on Nanuya Levu, a private island in Fiji.
In both sexes, the skin is light green to a gray or black background color, with two or three vertical white bands that multiply on the tail. In males, the dark background color is more intense.
It has a prominent angular dewlap, and the length of the tail exceeds twice the length of the body. In total, it can measure about 70 centimeters.
The Fiji crested iguana is herbivorous, feeding on leaves, shoots, fruits, and flowers from trees and shrubs such as Cevua (Vavaea amicorum), Kau loa (Diospyros elliptica), Qiqila (Micromelum minutum), Vau (Hibiscus tiliaceus), Yagata (Mallotus tiliifolius), Moive (Kingiodendrun platycarpum), Vesiwai, among others.
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