Abstract.A large-scale phylogenetic study is presented for Cucujoidea (Coleoptera), a diverse superfamily of beetles that historically has been taxonomically difficult. This study is the most comprehensive analysis of cucujoid taxa to date, with DNA sequence data sampled from eight genes (four nuclear, four mitochondrial) for 384 coleopteran taxa, including exemplars of 35 (of 37) families and 289 genera of Cucujoidea. Maximum-likelihood analyses of these data present many significant relationships, some proposed previously and some novel. Tenebrionoidea and Lymexyloidea are recovered together and Cleroidea forms the sister group to this clade. Chrysomeloidea and Curculionoidea are recovered as sister taxa and this clade (Phytophaga) forms the sister group to the core Cucujoidea (Cucujoidea s.n.). The nitidulid series is recovered as the earliest-diverging core cucujoid lineage, although the earliest divergences among core Cucujoidea are only weakly supported. The cerylonid series (CS) is recovered as monophyletic and is supported as a major Cucujiform clade, sister group to the remaining superfamilies of Cucujiformia. Currently recognized taxa that were not recovered as monophyletic include Cucujoidea, Endomychidae, Cerylonidae and Bothrideridae. Biphyllidae and Byturidae were recovered in Cleroidea. The remaining Cucujoidea were recovered in two disparate major clades: one comprising the nitidulid series + erotylid series + Boganiidae and Hobartiidae + cucujid series, and the other comprising the cerylonid series. Propalticidae are recovered within Laemophloeidae. The cerylonid series includes two major clades, the bothriderid group and the coccinellid group. Akalyptoischiidae are recovered as a separate clade from Latridiidae. Eupsilobiinae are recovered as the sister taxon to Coccinellidae. In light of these findings, many formal changes to cucujiform beetle classification are proposed. Biphyllidae and Byturidae are transferred to Cleroidea. The cerylonid series is formally recognized as a new superfamily,

RESUMO Neste estudo é apresentada a revisão dos gêneros Lachaerus Thomson, 1868 e Clavidesmus Dillon & Dillon, 1945 (Cerambycidae, Lamiinae, Onciderini). As espécies brasileiras são redescritas com base na morfologia externa e interna. Chaves para identificação de espécies e ilustrações são fornecidas. Os caracteres masculinos de Clavidesmus são apresentados pela primeira vez. Como resultados, são estabelecidas as sinonímias entre Orteguaza lichenigera Lane, 1958 e Clavidesmus metallicus (Thomson, 1868). Novas combinações: Clavidesmus rubigineus Dillon & Dillon, 1949 e Clavidesmus monnei Giorgi, 1998 são transferidas para Lachaerus. Novo registro de distribuição: Lachaerus fascinus (Audinet-Serville, 1835) para Argentina. Os gêneros de Onciderini que compartilham o engrossamento do antenômero III podem ser separados em dois grupos: (1) Lachaerus e Clavidesmus, que apresentam o terceiro antenômero nos dois sexos engrossados e (2) Eudesmus Audinet-Serville, 1835, Psyllotoxus Thomson, 1868, Oncideres Audinet-Serville, 1830, Taricanus Thomson, 1868 e Periergates Lacordaire 1872, com o terceiro antenômero engrossado somente nos machos.