Phylogenomics and revised classification of Lymexyloidea and Tenebrionoidea (Coleoptera: Polyphaga: Cucujiformia)

Abstract

Cucujiformia forms a substantial part of beetle diversity; however, relationships within this group remain unsettled. We used large-scale phylogenomic data to investigate early splits of the Tenebrionoid clade, focusing on the phylogenetic positions of Lymexylidae and Ripiphoridae. In concert with previous phylogenetic studies, we recovered Lymexyloidea as sister to Tenebrionoidea, and the clade Ripiphoridae + Mordellidae as sister to the remaining Tenebrionoidea. Based on their morphology and deep divergence, we designate the ‘mordelloid clade’ for Ripiphoridae and Mordellidae. Lymexyloidea contained two major clades: Lymexylidae, with subfamilies Lymexylinae and Atractocerinae, and Hylecoetidae sensu novo, with Hylecoetinae and Melittommatinae. Contrary to previous molecular studies, we found Ripiphoridae to be monophyletic, with Ptilophorinae or Ripidiinae as sister to all remaining clades. Additionally, we studied the morphology and phylogeny of fossil tenebrionoids, establishing the following new families: †Wuhuidae fam. nov., †Bellimordellidae fam. nov., and †Mirimordellidae fam. nov. Furthermore, †Praemordellidae stat. nov. (originally a subfamily of Mordellidae) were elevated to family rank, and †Yakutiinae subfam. nov. were proposed as a subfamily of Mordellidae. †Angimordella Bao et al. was transferred from Mordellinae to †Apotomourinae, and †Primaevomordellida Bao et al. from Reynoldsiellini to Mordellini. The newly proposed classification is summarized and discussed, with family-level identification keys provided for Lymexyloidea and the taxa in the ‘mordelloid clade’. New nomenclatural changes include the synonymies of Mordella bimaculata Fabricius syn. nov. with Mordella tricuspidata Goeze (now in Macrosiagon Hentz) and Trigonodera Dejean syn. nov. with Pelecotoides Laporte, and the earlier authorship of Ctenidia Laporte (1833, not 1840).