Phylogeny and classification of Cixiidae (Hemiptera, Fulgoromorpha): A new evolutionary scenario for the most diverse planthopper family

The Cixiidae represent the most diverse family within Hemiptera Fulgoromorpha, accounting for nearly 20% of the described species. A molecular phylogenetic analysis of 147 taxa reveals a new evolutionary scenario for the family, identifying four major lineages: borystheninian (restricted to the Borysthenini), oecleinian and pentastirinian, grouped in one clade, sister to the cixiinian one. In the oecleinian lineage, the Oecleini are paraphyletic, including the Bothriocerini. Three groups are identified in the pentastirinian lineage: the Hyalesthes⁺, Pentastiridius⁺ and Oliarus⁺ clades. Within the cixiinian lineage, as traditionally recognised, the Cixiini tribe is polyphyletic, involving a basally separated Achaemenes clade, a newly described Chidaeini trib. nov., and the ‘true Cixiini’ clade, which itself remains paraphyletic, including the Semonini. The Andini tribe appears paraphyletic, including the Brixiini, and the position of the Gelastocephalini is yet to be confirmed. Despite its significance, the sampling remains incomplete, hindering, in our opinion, the formal taxonomic recognition of these lineages with formal ranks for a new classification of the Cixiidae. Fossil-calibrated tree analysis indicates that Cixiidae originated in Lower Jurassic, approximately 181 million years ago. The four identified main lineages diverged during the Lower Jurassic in some 12 million years only, 155 million years ago. All currently recognised tribes and new major clades revealed with this study were present as early as the mid-Cretaceous, around 100 million years ago; however, the Bennini tribe and the ‘true Cixiini’ clade emerged later, some 75 million years ago.