A phylogeny, divergence-time estimations and taxonomic revision of the Tropidocephalini (Hemiptera: Fulgoromorpha: Delphacidae)

This is the authors' abstract. We don't add key points for this paper.

We sequenced the mitochondrial genomes of 59 species representing 18 genera of the delphacid tribe Tropidocephalini, and combined them with 30 additional datasets from online sources to reconstruct the phylogeny of the group. The genus Carinofrons is formally transferred from Tropidocephalini to Delphacini. The remaining 17 genera form a well-supported monophyletic group divided into 3 clades: the Malaxella+ clade containing only Malaxella, the Bambusiphaga+ clade, in which Bambusiphaga is paraphyletic with Specinervures nested within it, and the Malaxa+ clade, which is further subdivided into 4 lineages. Divergence-time analysis estimates the diversification of Tropidocephalini in the Early Cretaceous (133.68 Ma), the split between Bambusiphaga+ and Malaxa+ clades at 126.59 Ma, and the radiation of the Malaxella+ clade in the Eocene (∼51.16 Ma). Ancestral state reconstruction suggests bamboo feeding as the most likely ancestral condition among sampled extant Tropidocephalini, with a single secondary shift to grasses inferred in the Arcofaciella + Tropidocephala clade. Taxonomic implications include 3 generic synonymies: Arcifrons syn. nov. of Arcofacies, Lauriana syn. nov. of Malaxa, and Specinervures syn. nov. of Bambusiphaga, resulting in the following new combinations: Arcofacies arcifrontalis (Ding & Yang) comb. nov., Malaxa senticosa (Ren & Qin) comb. nov., Bambusiphaga nigrocarinata (Kuoh & Ding) comb. nov., B. basifusca (Chen & Li) comb. nov., and B. interrupta (Ding & Hu) comb. nov. In addition, the replacement name Bambusiphaga triprotrusa nom. nov. is proposed for Bambusiphaga basifusca Hou & Chen.