Biogeography of the Juan Fernández Archipelago: vicariance versus long-distance dispersal?

This article focuses on the biogeographical origins and colonization history of the Juan Fernández Archipelago in the southeast Pacific Ocean. Through a combined review of geological data and biological colonization records from 207 clades of angiosperms, ferns, landbirds, and coastal fishes, the study finds that the islands emerged only about 4.7 million years ago after a 3.5–3.8 million-year submergence gap, contradicting previous hypotheses of a continuous land presence since the mid-Cretaceous. Most terrestrial taxa originated from South America, while coastal fishes primarily trace back to the western and insular Pacific, reflecting ocean current patterns. The evidence supports long-distance dispersal as the exclusive mechanism for colonization, with no role for ancient landbridges or sunken landmasses, and suggests that some apparently ancient lineages reflect lineage loss rather than continuous presence.