The Chalcidoidea bush of life - Evolutionary history of a massive radiation of minute wasps

Capturing phylogenetic signal from a massive radiation can be daunting. The superfamilyChalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrantto phylogenetic resolution. Chalcidoidea are mostly parasitoid wasps that until now included27 families, 87 subfamilies and as many as 500,000 estimated species. We combined 1007exons obtained with Anchored Hybrid Enrichment with 1048 Ultra-Conserved Elements(UCEs) for 433 taxa including all extant families, over 95% of all subfamilies and 356 generachosen to represent the vast diversity of the superfamily. Going back and forth betweenmolecular results and our collective morphological and biological knowledge, we detectedinsidious bias driven by the saturation of nucleotide data and highlighted morphologicalconvergences. Our final results are based on a concatenated analysis of the least saturatedexons and UCE data sets (2054 loci, 284,106 sites). Our analyses support a sister relationshipwith Mymarommatoidea. Seven of the previously recognized families were notmonophyletic, so foundations for a new classification are discussed. Biology appearspotentially more informative than morphology, as illustrated by the elucidation of a clade ofplant gall associates and a clade of taxa with planidial first-instar larvae. The phylogenysuggests a shift from smaller soft-bodied wasps to larger and more heavily sclerotizedwasps. Deep divergences in Chalcidoidea coincide with an increase in insect families in thefossil record, and an early shift to phytophagy corresponds with the beginning of the"Angiosperm Terrestrial Revolution". Our dating analyses suggest a Middle Jurassic origin of174 Ma (167.3-180.5 Ma) and a crown age of 162.2 Ma (153.9-169.8 Ma) for Chalcidoidea.During the Cretaceous, Chalcidoidea underwent a rapid radiation in southern Gondwanawith subsequent dispersals to the Northern Hemisphere. This scenario is discussed withregard to knowledge about host taxa of chalcid wasps, their fossil record, and Earth'spaleogeographic history.