Past ecosystems drive the evolution of the early diverged Symphyta (Hymenoptera: Xyelidae) since the earliest Eocene

Abstract. Paleoxyela nearctica gen. et sp. nov., is described from the upper Eocene of Florissant Formation in Colorado. We placed nov. subfamily Macroxyelinae and tribe Macroxyelini based on numerous wing venation characters visible specimen. Proxyelia pankowskii lower Fossil Lake deposits Green River Wyoming. Xyeleciini These new records family Xyelidae are particular importance to better understand past diversity clade propose hypotheses about their diversification. Extant inhabit temperate Northern Hemisphere forests, most larvae feed conifers, which may explain why they relatively poorly diversified compared other symphytan families. suggest that global decline conifers reduced extant host trees partly Xyelidae. correlate biome repartition during xyelid.