Record migration of reptiles from millions of years ago. Pacific went to reach Fiji

The journey took place about 34 million years ago. The Fiji archipelago turned out to be their goal, and a means of transport – drifting rafts from vegetation.

Reptiles that traveled 8000 km through the ocean

For decades, scientists argued as the iguana reached the distant islands of the Pacific. Among the main theories there were assumptions about land migration from Asia, Australia and even South America by Antarctica. However, the latest discoveries of the team led by dr. Simona Scarpetta from the University of San Francisco completely change the approach to this question.

Researchers based their analyzes on the genetics of 14 contemporary species of legs and came to the conclusion that the ancestors of the lizards from Fiji came from North America.

“Dipsosaurus is the closest living relatives of the legs of Fiji-a kind of desert Jagana from the southwestern United States and North-West Mexico,” explained Scarpetta.

By Pacific on a raft

About 34 million years ago, ancient iguana could set off on an unprecedented journey from the west coast of North America. By covering almost 8000 kilometers through the Pacific Ocean, they finally reached Fiji. Contemporary genetic research indicates that this journey probably took place on floating mats from vegetation – the so -called rafts, consisting of torn out trees and shrubs floating on the water.

According to Scarpetta, “this type of rafting above the water is often described as the dispersion of ‘lottery’ – a rare event that allows the species to colonize an area that would otherwise be unattainable.”

Unusual adaptations to extreme conditions

Was such a journey for thousands of kilometers of ocean at all possible for land vertebrates? Researchers agree – Legion is an extremely resistant group of reptiles.

“If you were to choose a group of vertebrates that could survive the rafting for thousands of kilometers of open ocean, the legal ones are a great choice,” said Scarpetta.

A feature that distinguishes iguana from other animals is their ectothermics – the ability to regulate body temperature thanks to the heat of the ambient.

As noted by Dr. Jimmy McGuire from the University of California in Berkeley, “being ectothermic means that you do not use many food resources or fat reserves, maintaining an increased body temperature.” Compared to endotherms (warm -blooded mammals and birds), the ectotherms are up to 25 times more efficient in terms of energy demand.

How long did this extraordinary journey last?

Initially, scientists assumed that such a journey could last from four to 12 months. However, newer ocean models suggest that this time could be shorter.

“The journey could last from 2.5 to 4 months,” said Scarpetta.

Although the lack of access to a permanent source of food would be a challenge, legans as herbivores could eat rafting elements – leaves and bark. In addition, resistance to hunger and dehydration in the desert environment they came from could help them survive in the ocean.

Confirmation in modern history

The hypothesis about the dispersion by the water is not only theoretical. In 1995, after a hurricane, at least 15 green legs appeared on the beaches of Angilla in the Caribbean. It is believed that they arrived on rafts from torn trees from Guadeloupe, about 322 kilometers away.

This case, described in the 1998 study, is a strong confirmation that sea rafting can be a real mechanism for the spread of species.

Fossils proof of theory

Fossil evidence, or rather lack of them, play an important role in the new theory. The lack of fossils of the desert legwanów outside North America suggests that this continent was the original habitat of Fijan’s ancestors of lizards. In addition to genetic analysis, this fact significantly strengthens the hypothesis of transoceanic migration.

“This timeline undermines earlier theories that Legans could have a complex land journey from South America through Antarctica, which would take place much later in history,” noted Dr. Jimmy McGuire.

Complex genetic analysis

As Dr Shane Campbell-Staton from the University of Princeton emphasized, “in philogenic analyzes there is always a certain degree of uncertainty when you try to predict the time of discrepancy between species.

In this case, the authors have accurately collected many different types of genetic data and used many different models … to test their hypothesis and state that most of the results are largely consistent. ”