About 34 million years ago, a group of iguanas set out on an epic journey. This lofty band of reptiles traveled about 5,000 miles from the West Coast of North America to Fiji. Biologists believe this is the longest known oral dispersion of any land vertebrate. For more information about the survey results, please see Research published in the journal on March 17th Proceedings of the National Academy of Sciences (pnas).
Outlier iguana
There are over 2,100 species of Sub-order Iguania. This large group includes other reptiles, including chameleons, bearded dragons, and horned lizards. The Western Hemisphere family of lizards is the green green that most people think of when imagining an iguana. The Caribbean Sea has 45 different Iguanidae species and tropical, subtropical and desert regions of North, Central and South America, including the marine iguanas of the Galapagos. Chuck Wallas in the Southwest US.
However, the four iguana species found in the Pacific Islands of Fiji and Tonga are slightly outliers. They sit in the middle of the Pacific Ocean, and scientists have long debated how they got there.
Move around the ocean
Water overwater dispersion– Where terrestrial creatures move from one land to another through water bodies – the main way plants, animals, and even humans live on newly formed islands. This process often leads to the evolution of new species and ecosystems.
This study suggests that the original ancestors of the Iguanas in Fiji were consistent with the formation of the islands by the volcanic . Scientists estimate that it arrived about 34 million years ago, based on genetic evidence. Fiji Iguanas (Brakirovs) and their closest relatives, the North American desert iguanas (Dipsaurus) Indicates signs of genetic divergence.
Biologists initially suggested that Fijian iguanas were initially more widely around the Pacific Ocean, but may have descended from an older strain that has since died. Another theory is the iguana Traveled from the tropical parts of South America And through Antarctica and Australia. There is no genetic or fossil evidence to support these previous theories, but new genetic analyses do.
“The Fijian iguanas are found to be most closely related to the desert iguanas in North America, something that was previously unknown, and the Fijian iguanas lineage has been split relatively recently from their sister lineage, close to 30 million years ago. Francis’ paleontologists and herpetologists; said in a statement.
“It seems crazy that they arrived directly from North America in Fiji,” said Jimmy McGuire, a research co-author at the University of California, and a Heleigh Petrogist at Berkeley. said in a statement. “However, alternative models involving colonization from adjacent lands have known that they have arrived in Fiji within the last 34 million years, suggesting that Fiji exists now.
Built-in travel snacks
Today’s sailors can normally reach Fiji from California about a month later. However, the group of iguanas takes a little longer. Reptiles need to jump on several fluorescent membranes, pass through the bass and cross the equator to Fiji and Tonga.
Luckily, iguanas are big and herbivorous, and can go for long periods of time without food or water. Their “rafts” were made from uprooted trees that served food to eat along the way.
“I could imagine knocking on trees with bundles of iguanas and eggs and catching and rafting the ocean current,” Scalpetta said.
Based on several fossils found in East Asia, biologists believed that the extinct population of Iguanid currently lives around the Pacific edge, and that the island was heading towards the middle of the Pacific Ocean. They may have used Beringland Bridge for travelling from North America and across Indonesia and Australiaor followed the Humboldt flow along the Pacific coast of the Americas. Previous genetic analyses of some iguanide lizard genes were inconclusive about how Fijian iguanas are associated with those found elsewhere.
“These various analyses infer different relationships, and none of them have particularly strong support,” McGuire said. “So there was still this uncertainty as to where Brachyrofus actually fits within the iguanide phylogeny.”
Scarpetta collected genome-wide sequence DNA from More 4,000 genes from tissues of over 200 Iguanian specimens from the museum collection. Genetic data showed that Fijian iguanas are most closely related to iguanas of the genus Dipsaurus. The most widespread species within the genus are the desert iguanas of North American. It adapts to life amid the burning heat of the deserts in the southwestern United States and northern Mexico. Other species within this genus are native to Santa Catalina Island, located in the Sea of Cortez.
“Iguanas and desert iguanas in particular are resistant to starvation and dehydration, so my thought process is when I need a group of vertebrates or a group of lizards that can make up 8,000 kilometres. [4,970 mile] A journey across the Pacific Ocean with masses of vegetation will be one ancestor, like desert iguanas,” Scalpetta said.
Genetic analysis was determined to be both the lineage – Brakilohus and dipsosaurus.It branched out about 34 million years ago. This revised analysis is inconsistent with previous theories of the origins of the Fijian iguana.
[ Related: Pink Iguana hatchlings spotted for the first time on the Galápagos in decades. ]
“When you really don’t know where Brakirovs Once they fit into the base of the tree, there’s almost everywhere where they came from,” McGuire said. Brakirovs We already have ocean and land iguanas in the Galapagos, so we were born from South America as they are almost certainly dispersed from the mainland to the islands. ”
This new analysis excludes the idea that iguanas were born in South America. Furthermore, the iguanas may have landed on the island just shortly after about 34 million years ago, as the Fiji Islands themselves emerged from the sea. Other Pacific Islands besides Fiji and Tonga Iguanas may also be holding them. However, volcanic islands disappear just as quickly as they appear, so some evidence of other Pacific island iguanas may have been lost.
The team continues to analyze data across the Iguanian lizard genome, gain a better understanding of evolutionary relationships and learn more about interactions through time and space.
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