Toward a new phylogeny-based classification of Flatidae (Hemiptera: Fulgoromorpha): a diversification shaped by...

Despite being one of the most diverse planthopper families with broad distribution and ecological significance, the internal classification of Flatidae has remained largely phenetic and of limited phylogenetic relevance. Here, we present the first comprehensive phylogenetic analysis of Flatidae, based on a multilocus dataset and broad, though still incomplete, genus-level sampling. Our results challenge the monophyly of most traditional subfamilies, tribes, and subtribes, and reveal three previously unrecognized major lineages with strong biogeographic structure: the siphantinian, flatinian, and selizinian lineages. The latter two comprise, respectively, three and five well-supported sublineages: phromniinan, phyllyphantinan, and flatinan for the former; and sisciinan, phantinan, selizinan, cryptoflatinan, and the Makaya⁺ sublineage for the latter. The origin of Flatidae is estimated to date back to the Late Jurassic, with diversification in their ancestral area, likely the Oriental region or the Old World, occurring during the Early Cretaceous. The geographic distributions of the newly emerged lineages show strong coherence with their phylogenetic structure. We interpret the early diversification of Flatidae as closely tied to the rise of angiosperms during the Cretaceous, which provided novel ecological opportunities and facilitated both radiation and long-term persistence across continents. Herein, we provide a new evolutionary framework for future morphological, ecological, and taxonomic research on Flatidae, and we contribute to a deeper understanding of diversification patterns among higher Fulgoroidea.