What evidence suggests that coraciiform birds originated in the Old World?

The evidence suggesting an Old World origin for coraciiform birds is primarily based on their current distribution, diversity, and the fossil record.1

• Geographic Abundance: Coraciiforms exhibit significantly higher diversity and abundance in the Old World tropics compared to the New World. Africa, including Madagascar, hosts eight of the 10 recognized families, suggesting this region may have been a center of their evolution.12
• Ecological Niche Filling: The relative scarcity of these birds in tropical America is likely due to the fact that many ecological niches were already occupied by established piciform and passeriform families by the time coraciiform stock arrived in the New World.1
• Fossil Evidence: Paleontological findings support an early presence in the Old World, with fossils of hornbills, rollers, and kingfishers dating back to the Eocene and Oligocene epochs discovered in Europe.1
• Dispersal Patterns: It is believed that ancestral kingfisher stock reached the New World via the Bering Strait, eventually giving rise to endemic groups like motmots and todies.1