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The Mesozoic fossil record of the family Cerophytidae is critically reviewed. The fossil data is combined with the characters of the recent representatives of Cerophytidae to build a new phylogenetic hypothesis of their relationships. Twenty-three in-group taxa and three out-groups were included in a maximum parsimony cladistic analysis based on 32 adult characters. The resulting tree confirms the family Cerophytidae as a monophylum with two weakly supported clades, segregating most of the extinct Mesozoic and extant genera into separate clades. The new concept of the family Cerophytidae is presented to reconcile characters of the Mesozoic and recent taxa, without recognition of Aphytocerinae Kirejtshuk, 2013. Lebanophytum Kirejtshuk and Azar (=Lebanophytidae Kirejtshuk in Kirejtshuk and Azar, 2013), originally placed in Cerophytidae, is removed from Elateroidea and placed in the cucujoid family Cryptophagidae. The family Lebanophytidae Kirejtshuk in Kirejtshuk and Azar, 2013, based on this genus, becomes a junior synonym of Cryptophagidae Kirby, 1826 (syn. nov.). The two species Praelaterium problematicum Dolin, 1973 and Elaterocoleus oculatus Dolin, 1973, originally included in the family Praelateriidae Dolin, are moved to the family Cerophytidae, and Praelateriidae Dolin, 1973 is regarded as a junior synonym of Cerophytidae Latreille, 1834 (syn. nov.). Jurassophytum cleidecostae Yu, Ślipinski and Pang gen. et sp. nov. from the Middle Jurassic Daohugou beds (Inner Mongolia, northeastern China), and Amberophytum birmanicum Yu, Ślipinski and Pang gen. et sp. nov., Necromeropsis minutus Yu, Ślipinski and Pang gen. et sp. nov., Brachycerophytum cretaceum Yu, Ślipinski and Pang sp. nov. and Cerophytum albertalleni Yu, Ślipinski and Pang sp. nov. from the Upper Cretaceous amber deposits of Myanmar are described and illustrated.

A new net-winged beetle, Burmolycus compactus gen. et sp. nov. (Coleoptera, Elateroidea, Lycidae), is described from mid-Cretaceous Burmese amber and the new tribe Burmolycini trib. nov. is erected for this species in Dexorinae Bocak et Bocakova, 1989. B. compactus is the oldest amber inclusion of a net-winged beetle. The discovery suggests the start of Lycidae diversification at least in the Mid-Cretaceous. The fossil was discovered in the area of the highest phylogenetic diversity of extant net-winged beetles, in deposits with a rich beetles fauna. The species is a member of the putative early radiation of this family and shows relationships with Afrotropical Dexorinae from which it differs in the dilated apical palpomeres, serrate antennae, and fully metamorphosed females. Burmolycus compactus shares 10-segmented antennae with several genera with proved or hypothesized neotenic females. The general appearance of Cretaceous B. compactus is surprisingly similar to extant net-winged beetles and may represent the example of their long-term morphological stasis.

Bioluminescence, the emission of visible light in a living organism, is an intriguing phenomenon observed in different species and environments. In terrestrial organisms, the bioluminescence is observed mainly in beetles of the Elateroidea superfamily (Coleoptera). Several phylogenetic studies have been used different strategies to propose a scenario for the origin and evolution of the bioluminescence within this group, however some of them showed incongruences, mainly about the relationship of the bioluminescent families. In order to increase the number of molecular markers available for Elateroidea species and to propose a more accurate phylogeny, with high supported topology, we employed the Next-Generation Sequencing (NGS) methodology to perform the RNA-Seq analysis of luminescent (Elateridae, Phengodidae, Rhagophthalmidae, and Lampyridae) and non-luminescent (Cantharidae) species of Neotropical beetles. We used the RNA-Seq data to construct a calibrated phylogeny of Elateroidea superfamily using a large number of nuclear molecular markers. The results indicate Lampyridae and Phengodidae/Rhagophthalmidae as sister-groups, suggesting that the bioluminescence evolved later in Elateridae than other families (Lampyridae, Phengodidae, and Rhagophthalmidae), and indicating the Upper Cretaceous as the period for the main diversification of Elateroidea bioluminescent species.

Bioluminescence in the superfamily Elateroidea is produced by specific light organs distributed in different parts of the body depending on the life stage and family. Whereas the luciferin-luciferase system is well known, the molecular control of bioluminescence, the biosynthetic route of luciferin, and the molecular differentiation of photogenic tissue in Elateridae remain enigmatic. With the aim to improve the knowledge about these questions, we performed the RNA-Seq analysis of lanterns and fat body of the Brazilian click beetle larvae: Pyrearinus fragilis (luminescent) and Conoderus sp. (non-luminescent) and compared the gene products contents and their abundance among these tissues. For the first time, we showed that the fat body of luminescent click beetle displays luminescence. We also analyzed some gene products expression patterns in lantern and fat body of Elateridae. Several of them, which are potentially involved with bioluminescence and its control are also found in the transcriptional profile of the firefly Aspisoma lineatum (Lampyridae) and the railroad worm Phrixothrix hirtus (Phengodidae). These gene products were observed in both lanterns and fat body of elaterid species, however with low abundance in the fat body. The results indicate that in Elateridae, the bioluminescent tissue also originated from the fat body. In P. fragilis, we observed two luciferase/luciferase-like enzymes with high abundance, one in the lantern and a different one in the fat body, indicating the possibility of two distinct isoenzymes involved in the bioluminescence in the lantern and fat body of Elateridae species, such as observed in fireflies.

Newly available specimens of Prototrichalus Molino-Olmedo et al., 2020 yield further diagnostic characters for the phylogenetic classification of this recently described genus. We show that Prototrichalus has tarsal formula 5-5-4, short trochanters, kidney-shaped eyes; the antennae are inserted in front of eyes and palpomeres substantially differ from all net-winged beetles. These characters identify tenebrionoid families as potential relatives of Prototrichalus. For example, extant and Eocene Ischalia Pascoe, 1860 (Anthicidae: Ischaliinae) resemble Prototrichalus in the structure of elytral costae and costal interspaces. As a result, we transfer Prototrichalus from Elateroidea: Lycidae to Tenebrionoidea incertae sedis. The earlier claim that Prototrichalus pushes the origin of Metriorrhynchini beyond earlier estimates is incorrect. The radiation of major net-winged beetle lineages was estimated ~123 million years ago and the deepest splits within Metriorrhynchini to 77–98 million years ago and these estimations were not considered in the discussion on Prototrichalus. We assume that the superficial similarity in the general appearance of Prototrichalus and net-winged beetles can be a result of mimicry in already very diverse Cretaceous beetles, but only further discoveries of additional species can provide robust evidence for the convergent evolution.

Bioluminescence in beetles is found in the Elateroidea superfamily, which includes Elateridae, Lampyridae, Rhagophthalmidae, and Phengodidae families. Despite sharing the same biochemical system, it is unclear whether the lanterns and the bioluminescent system share a common origin or not. To better understand the molecular differentiation of photogenic from non-photogenic tissues and the molecular physiology of these tissues, we compared the transcriptional profiles of the lateral lanterns and fat body in Phrixothrix hirtus railroad worm (Phengodidae) and the abdomen of the non-luminescent Chauliognathus flavipes (Cantharidae). We observed gene products involved in pheromone biosynthesis in all tissues and four distinct opsin gene products in C. flavipes, more than expected when compared to the transcriptional analysis of lampyrid eyes. We also observed several gene products potentially associated with bioluminescence in P. hirtus lantern and in C. flavipes body, whereas in the fat body of P. hirtus we found only a single copy of luciferase homolog enzyme. Altogether these results suggest that the photogenic tissue of phengodid lanterns has distinct origin from fireflies lanterns, and also the existence of a latent bioluminescent potential in the fat body tissue of some Elateroidea families.

In the present study, we describe the sperm morphology of 11 species of Elateriformia (9 elaterids, 1 lampyrid and 1 buprestid) using transmission electron microscopy. All species exhibited sperm that is not usually observed in insects in general. The most highlighted features are the displacement of the nucleus running parallel to the flagellar components, hitherto observed only in coccinellid and carabid beetles, and the presence of thin and dense structures along the nucleus, probably derived from the centriole adjunct, a feature that is so far exclusive to these insects. The other structures are a typical axoneme for insects with 9 + 9 + 2 microtubules, in a position diametrically opposite relative to the nucleus, two slender, symmetrical mitochondrial derivatives and a pair of discrete accessory bodies. This arrangement provides a bilaterally symmetrical flagellum, which favourably influences sperm hydrodynamics, as will be discussed. The occurrence of this unusual structural arrangement in the sperm of species from superfamilies that are phylogenetically as distant as Elateroidea and Buprestoidea support the monophyly of the infraorder Elateriformia, as proposed by some previous molecular studies.

With nine described species in two genera, Brachypsectridae is a small and widespread elateroid family. Fossil brachypsectrids have been confined to the Baltic and Dominican ambers, and very little is known about the early evolution of Brachypsectridae in the Mesozoic era. Here we describe and illustrate the first Mesozoic brachypsectrid, Vetubrachypsectra burmitica gen. et sp. nov., based on a male adult entombed in the mid-Cretaceous amber from northern Myanmar, approximately 99 million years ago. Vetubrachypsectra has a close affinity to the extant Brachypsectra, but primitively retains many plesiomorphic characters, including long antennae, tibial spurs 2-2-2 and male parameres without hook. Our discovery of a new Mesozoic brachypsectrid species pushes back the fossil record of Brachypsectridae by approximately 55 million years, which has great significance for further dating of phylogenetic trees of beetles.

Artematopodidae is small basal group of elateroid beetles. Definitive Mesozoic artematopodids are currently confined to the Middle Jurassic Daohugou biota. Here we report a new genus and species, Cretobrevipogon breviantennatus gen.et sp. nov., from the Lower Cretaceous Yixian Formation (ca. 125 Ma) in Liaoning Province, northeastern China. Cretobrevipogon exhibit many diagnostic features of the extant family Artematopodidae, such as paired carinae on prosternum and more importantly, an apical interlocking tongue on the ventral side of elytron. Phylogenetic analyses indicate that Cretobrevipogon is closely related to the Middle Jurassic Sinobrevipogon. They share a presumably plesiomorphic character, i.e. mesocoxal cavitiy closed by mesepimeron and anterolateral edge of metanepisternum. The discovery of a new genus from the Early Cretaceous highlights the morphological disparity and palaeodiversity of the family in the Mesozoic. Artematopodidae probably represent a relictual elateroid family that once diversified in the middle–late Mesozoic.

Two new genera and two new species of fossil Throscidae: Potergosoma gratiosa gen. et sp. nov. and Rhomboaspis laticollis gen. et sp. nov. are described from the Lower Cretaceous Lebanese amber and are compared with extant and extinct genera. The described amber inclusions are the oldest known representatives of the family Throscidae. Some hypotheses on the phylogeny of the family Throscidae and the position of it in the superfamily Elateroidea are discussed.

The Ototretinae are revised using comparative morphology of adults. All recognized genus-group taxa are redescribed and illustrated and a key to genera is provided. The concept of Ototretinae within Lampyridae is clarified and the taxonomic placement with the phylogenetic relationships of several taxa formerly associated as cantharoids is discussed. Ototretadrilus Pic, 1921 is considered to be closely related to Drilaster Kiesenwetter, 1879 and consequently Ototretadrilus is transferred from the subfamily Ototretadrilinae Crowson, 1972 (Lampyridae) to the Ototretinae McDermott, 1964. Therefore, the monotypic Ototretadrilinae is considered to be a younger subjective synonym of Ototretinae McDermott, 1964. On the basis of a thorough examination of morphological characters and in congruence with DNA data analyses, the subfamily Ototretinae is transferred from Elateriformia incertae sedis ( Lawrence et al., 2010 ) to Lampyridae, the genera Harmatelia Walker, 1858 and Stenocladius Fairmaire, 1878 are transferred from Elateriformia incertae sedis ( Lawrence et al., 2010 ) to the Ototretinae, and simultaneously Baolacus Pic, 1915 is transferred from Lampyridae incertae sedis ( Geisthardt and Sato, 2007 ) to the Ototretinae. As Palpotreta was found to be very close to Eugeusis, Palpotreta Janisova et Bocakova, 2009 is considered to be a younger subjective synonym of Eugeusis Westwood, 1853, and simultaneously, Eugeusis ramicornis (Janisova et Bocakova, 2009) n. comb. is proposed for Palpotreta ramicornis Janisova et Bocakova, 2009. The genus Brachypterodrilus Pic, 1918 was found to be related to ototretines, and therefore it is transferred from Drilidae to Lampyridae (Ototretinae). Cladiodrilus minutus Pic, 1920 and Rhipidiodrilus atricolor Pic, 1943 are considered to be closely related to Brachypterodrilus pallidipes Pic, 1918, and therefore Cladiodrilus Pic, 1920 and Rhipidiodrilus Pic, 1943 are considered to be younger subjective synonyms of Brachypterodrilus Pic, 1918. Consequently, Brachypterodrilus minutus (Pic, 1920) n. comb. and B. atricolor (Pic, 1943) n. comb. are proposed. Hydaspoides n. gen. is proposed with the type-species H. kanarensis n. sp. Within the genus Drilaster three new subgenera: Kerincius n. sg. with the type species Drilaster (Kerincius) medioniger n. sp., Apodrilus n. sg. with the type species Drilaster (Apodrilus) agcoensis n. sp., and Loksadodrilus n. sg. with the type species Drilaster subvittatus (Pic, 1931) are proposed as new to science. Finally, three type-species are designated: Flabellototreta fruhstorferi Pic, 1911 is fixed to be the type species of the genus Flabellototreta Pic, 1911, Harmatelia bilinea Walker, 1858 is fixed as the type species of Harmatelia Walker, 1858, and Ototretadrilus atritarsis Pic, 1921 is fixed as the type species of Ototretadrilus Pic, 1921.

Bioluminescence in beetles is dependent upon the enzyme luciferase. It has been hypothesised luciferase evolved from a fatty acyl-CoA synthetase gene deriving a novel bioluminescent function (neofunctionalization) after a gene duplication event. We evaluated this hypothesis within a phylogenetic framework using independent evidence obtained from the genome of Tribolium castaneum, published luciferase genes and novel luciferase and luciferase-like sequences. This phylogenetic study provides evidence for a large gene family of luciferase and luciferase-like paralogues in bioluminescent and non-bioluminescent beetles. All luciferase sequences formed a clade supporting a protoluciferase existing prior to the divergence of the Lampyridae, Elateridae and Phengodidae (Elateroidea). Multiple luciferase genes were identified from members of the Photurinae and the Luciolinae indicating complex gene duplication events within lampyrid genomes. The majority of luciferase residues were identified to be under purifying selection as opposed to positive selection. We conclude that beetle luciferase may have arisen from a process of subfunctionalization as opposed to neofunctionalization early on in the evolution of the Elateroidea.

Cantharoid beetles are distinctive for their leathery soft elytra and conspicuous color or bioluminescence, and many of the members are equipped with chemical defenses. Thus, the vivid coloration of Cantharidae and Lycidae and the bioluminescence in Lampyridae and Phengodidae appear to be aposematic signals. However, the evolutionary aspect of their aposematism is not well understood, because the classification of the families remains controversial. In this study, we performed molecular phylogenetic analyses of species from cantharoid families, based on nucleotide sequence comparisons of nuclear 18S ribosomal DNA. The results shows that the luminous species Rhagophthalmus ohbai, which had sometimes been classified in Lampyridae, is excluded from a lampyrid clade and associates with the taxa of Phengodidae. The molecular data also suggests that four major subfamilies of Cantharidae (Cantharinae, Chauliognathinae, Malthininae, and Silinae) form a clade. The six subfamilies of Lampyridae are grouped and classified into two sublineages: Amydetinae+Lampyrinae+Photurinae and Cyphonocerinae+Luciolinae+ Ototretinae. Genera Drilaster and Stenocladius are the members of Ototretinae in Lampyridae. These results conform to traditional taxonomy but disagree with more recent cladistic analyses. Based on these findings, we propose an evolutionary process of bioluminescence and aposematism in cantharoids: the clades of Cantharidae, Lampyridae, Lycidae, and Phengodidae have evolved aposematic coloration; subsequently Lampyridae and Phengodidae acquired bioluminescence; and these four major cantharoid families achieved their current adaptive diversities. © 2007 Elsevier B.V. All rights reserved.