No abstract

Beetles constitute the most biodiverse animal order with over 380 000 described species and possibly several million more yet unnamed. Recent phylogenomic studies have arrived at considerably incongruent topologies and widely varying estimates of divergence dates for major beetle clades. Here, we use a dataset of 68 single-copy nuclear protein-coding (NPC) genes sampling 129 out of the 193 recognized extant families as well as the first comprehensive set of fully justified fossil calibrations to recover a refined timescale of beetle evolution. Using phylogenetic methods that counter the effects of compositional and rate heterogeneity, we recover a topology congruent with morphological studies, which we use, combined with other recent phylogenomic studies, to propose several formal changes in the classification of Coleoptera: Scirtiformia and Scirtoidea sensu nov ., Clambiformia ser. nov. and Clamboidea sensu nov. , Rhinorhipiformia ser. nov ., Byrrhoidea sensu nov. , Dryopoidea stat. res. , Nosodendriformia ser. nov. and Staphyliniformia sensu nov ., and Erotyloidea stat. nov ., Nitiduloidea stat. nov . and Cucujoidea sensu nov., alongside changes below the superfamily level. Our divergence time analyses recovered a late Carboniferous origin of Coleoptera, a late Palaeozoic origin of all modern beetle suborders and a Triassic–Jurassic origin of most extant families, while fundamental divergences within beetle phylogeny did not coincide with the hypothesis of a Cretaceous Terrestrial Revolution.

Kundrata, R. & Bocak, L. (2011). The phylogeny and limits of Elateridae (Insecta, Coleoptera): is there a common tendency of click beetles to soft-bodiedness and neoteny? -Zoologica Scripta, 40, 364-378. Phylogenetic relationships in Elateroidea were investigated using partial 18S and 28S rDNA and rrnl and cox1 mtDNA sequences with special interest in the phylogeny of Elateridae and the position of soft-bodied lineages Drilidae and Omalisidae that had been classified as families in the cantharoid lineage of Elateroidea until recently. Females in these groups are neotenic and almost completely larviform (Drilidae) or brachypterous (Omalisidae). The newly sequenced individuals of Elateridae, Drilidae, Omalisidae and Eucnemidae were merged with previously published datasets and analysed matrices include either 155 taxa with the complete representation of fragments or 210 taxa when some fragments were missing. The main feature of inferred phylogenetic trees was the monophyly of Phengodidae + Rhagophthalmidae + Omalisidae + Elateridae + Drilidae with Omalisidae regularly occupying a basal node in the group; Drilidae were embedded as a terminal lineage in the elaterid subfamily Agrypninae and soft-bodied Cebrioninae were a part of Elaterinae. The soft-bodied males and incompletely metamorphosed females originated at least three times within the wider Elateridae clade. Their atypical morphology has been considered as a result of long evolutionary history and they were given an inappropriately high rank in the previous classifications. The frequent origins of these modifications seem to be connected with modifications of the hormonal regulation of the metamorphosis. The superficial similarity with other soft-bodied lineages, such as Cantharidae, Lycidae, Lampyridae, Phengodidae and Rhagophthalmidae is supposed to be a result of homoplasious modifications of the ancestral elateroid morphology due to the incomplete metamorphosis. The results of phylogenetic analyses are translated in the formal taxonomic classification. Most Drilidae are placed in Elateridae as a tribe Drilini in Agrypninae, whilst Pseudeuanoma and Euanoma are transferred from Drilidae to Omalisidae. The subfamily Cebrioninae is placed in Elaterinae as tribes Cebrionini and Aplastini. Oxynopterini, Pityobiini and Semiotini are lowered from the subfamily rank to tribes and classified in Denticollinae.

The ongoing exploration of biodiversity and the implementation of new molecular tools continue to unveil hitherto unknown lineages. Here, we report the discovery of three species of neotenic beetles for which we propose the new family Iberobaeniidae. Complete mitochondrial genomes and rRNA genes recovered Iberobaeniidae as a deep branch in Elateroidea, as sister to Lycidae (net-winged beetles). Two species of the new genus Iberobaenia, Iberobaenia minuta sp. nov. and Iberobaenia lencinai sp. nov. were found in the adult stage. In a separate incidence, a related sequence was identified in bulk samples of soil invertebrates subjected to shotgun sequencing and mitogenome assembly, which was traced to a larval voucher specimen of a third species of Iberobaenia. Iberobaenia shows characters shared with other elateroid neotenic lineages, including soft-bodiedness, the hypognathous head, reduced mouthparts with reduced labial palpomeres, and extremely small-bodied males without strengthening structures due to miniaturization. Molecular dating shows that Iberobaeniidae represents an ancient relict lineage originating in the Lower Jurassic, which possibly indicates a long history of neoteny, usually considered to be evolutionarily short-lived. The apparent endemism of Iberobaeniidae in the Mediterranean region highlights the importance of this biodiversity hotspot and the need for further species exploration even in the well-studied European continent.

Click-beetles (Coleoptera: Elateridae) are an abundant, diverse, and economically important beetle family that includes bioluminescent species. To date, molecular phylogenies have sampled relatively few taxa and genes, incompletely resolving subfamily level relationships. We present a novel probe set for anchored hybrid enrichment of 2260 single-copy orthologous genes in Elateroidea. Using these probes, we undertook the largest phylogenomic study of Elateroidea to date (99 Elateroidea, including 86 Elateridae, plus 5 non-elateroid outgroups). We sequenced specimens from 88 taxa to test the monophyly of families, subfamilies and tribes. Maximum likelihood and coalescent phylogenetic analyses produced well-resolved topologies. Notably, the included non-elaterid bioluminescent families (Lampyridae + Phengodidae + Rhagophthalmidae) form a clade within the otherwise monophyletic Elateridae, and Sinopyrophoridae may not warrant recognition as a family. All analyses recovered the elaterid subfamilies Elaterinae, Agrypninae, Cardiophorinae, Negastriinae, Pityobiinae, and Tetralobinae as monophyletic. Our results were conflicting on whether the hypnoidines are sister to Dendrometrinae or Cardiophorinae + Negastriinae. Moreover, we show that fossils with the eucnemid-type frons and elongate cylindrical shape may belong to Eucnemidae, Elateridae: Thylacosterninae, ancestral hard-bodied cantharoids or related extinct groups. Proposed taxonomic changes include recognition of Plastocerini as a tribe in Dendrometrinae and Hypnoidinae stat. nov. as a subfamily within Elateridae.