🦎Iguanas rafted more than 8,000 km from North America to Fiji

Fijian Crested Iguana (Brachylophus vitiensis) resting on a coconut palm on the island of Fiji in the South Pacific. The four species of iguanas that inhabit Fiji and Tonga today are descended from ancestors who colonized the island over the past 34 million years, likely by rafting 5,000 miles across the Pacific Ocean from western North America.

Founder-event speciation can occur when one or more organisms colonize a distant, unoccupied area via long-distance dispersal, leading to the evolution of a new species lineage.

👩‍🔬The authors investigated the occurrence and timing of the largest known long-distance oceanic dispersal event in the history of terrestrial vertebrates - the the rafting of iguanas from North America to Fiji.

Iguanas are well-known species that colonized the Caribbean and the Galápagos islands. However, the origin of Fijian iguanas had not been comprehensively tested. The scientists estimated the phylogenetic relationships and evolutionary timescale of the iguanid lizard radiation using genome-wide exons and ultraconserved elements (UCEs).

👩‍🔬Those data indicate that the closest living relative of extant Fijian iguanas is the North American desert iguana and that the two taxa likely diverged during the late Paleogene near or after the onset of volcanism that produced the Fijian archipelago. 

🕵Biogeographic models estimate North America as the most probable ancestral range of Fijian iguanas. The analyses support the hypothesis that iguanas reached Fiji via an extraordinary oceanic dispersal event from western North America, and which spanned a fifth of the earth’s circumference (>8,000 km). 

👀Overwater rafting of iguanas from North America to Fiji strengthens the importance of founder-event speciation in the diversification of iguanids and elucidates the scope of long-distance dispersal across terrestrial vertebrates.

photo: Nicholas Hess

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If you want more information, I encourage you to read the references:

👉S.G. Scarpetta,R.N. Fisher,B.R. Karin,J.B. Niukula,A. Corl,T.R. Jackman,& J.A. McGuire,  Iguanas rafted more than 8,000 km from North America to Fiji, Proc. Natl. Acad. Sci. U.S.A. 122 (12) e2318622122

#Reptilia #Oceania #transmarinedispersal #taxonomy #phylogenetics #iguana #pacific #archipelago #science #Herpetology #lizards #fiji