Ecological interactions are fundamental to understanding species' trophic relationships and the evolution of ecosystem functions. However, the fossil record seldom captures these intricate dynamics, as most fossils preserve individual organisms rather than the interactions that shaped ancient ecosystems. Here, we describe a new genus of bark-gnawing beetles (Trogossitidae), Rutrizoma gen. nov., from mid-Cretaceous amber in northern Myanmar. This fossil genus reveals a rare combination of predatory and antipredatory adaptations, shedding light on the ecological complexity of Mesozoic forest ecosystems. Rutrizoma has specialized morphological features, such as shortened elytra and unidentate mandibles, suggesting an active predatory lifestyle in narrow wood galleries. Interestingly, some morphological traits of Rutrizoma mirror those of its potential prey, particularly bostrichid beetles, from the same amber deposit. One such trait is its specialized abdominal declivity, which probably functioned as a protective shield against predators and competitors, representing marked convergence with the elytral declivity of other subcortical beetles, such as bark and ambrosia beetles (Scolytinae and Platypodinae) and Bostrichidae. The presence of phoretic mites associated with Rutrizoma, along with co-preserved bostrichid prey, underscores the complex community dynamics beneath Cretaceous tree bark. This finding reveals a subcortical ecosystem that parallels modern ecological interactions.

• Keywords
• Cretaceous, beetle, defence, ecological interaction, phragmosis,
• MeSH
• Biological Evolution MeSH
• Coleoptera * anatomy & histology   physiology   classification   MeSH
• Ecosystem MeSH
• Amber MeSH
• Predatory Behavior MeSH
• Fossils * anatomy & histology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Myanmar MeSH
• Names of Substances
• Amber MeSH

The click beetles (Elateridae) represent the major and well-known group of the polyphagan superfamily Elateroidea. Despite a relatively rich fossil record of Mesozoic Elateridae, only a few species are described from the Upper Cretaceous Burmese amber. Although Elateridae spend most of their lives as larvae, our knowledge on immature stages of this family is limited, which is especially valid for the fossils. So far, only a single larval click beetle has been reported from Burmese amber. Here, we describe two larval specimens from the same deposit which based on their morphology unambiguously belong to the predominantly Southern Hemisphere subfamily Pityobiinae, being the most similar to the representatives of tribe Tibionemini. However, since the larvae of the closely related bioluminescent Campyloxenini have not yet been described, we place our specimens to Tibionemini only tentatively. One species of Pityobiinae was recently described from Burmese amber based on adults, and we discuss if it can be congeneric with the here-reported larvae. Recent representatives of the Tibionemini + Campyloxenini clade are known from South America and New Zealand, and this group is hypothesized to have a Gondwanan origin. Hence, the newly discovered Burmese amber larvae may further contribute to a recently highly debated hypothesis that biota of the resin-producing forest on the Burma Terrane, which was probably an island drifting northward at the time of amber deposition, had at least partly Gondwanan affinities. The discovery of enigmatic click beetle larvae in the Upper Cretaceous Burmese amber sheds further light on the palaeodiversity and distribution of the relatively species-poor Gondwanan clade of click beetles, which contain a recent bioluminescent lineage, as well as on the taxonomic composition of the extinct Mesozoic ecosystem.

• Keywords
• Australia, Distribution, Elateridae, Fossil, Morphology, Pityobiinae,
• MeSH
• Coleoptera * anatomy & histology   classification   MeSH
• Phylogeny MeSH
• Amber * MeSH
• Larva * anatomy & histology   MeSH
• Fossils * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Myanmar MeSH
• Names of Substances
• Amber * MeSH

The beetle superfamily Elateroidea comprises the most biodiverse bioluminescent insects among terrestrial light-producing animals. Recent exceptional fossils from the Mesozoic era and phylogenomic studies have provided valuable insights into the origin and evolution of bioluminescence in elateroids. However, due to the fragmentary nature of the fossil record, the early evolution of bioluminescence in fireflies (Lampyridae), one of the most charismatic lineages of insects, remains elusive. Here, we report the discovery of the second Mesozoic bioluminescent firefly, Flammarionella hehaikuni Cai, Ballantyne & Kundrata gen. et sp. nov., from the Albian/Cenomanian of northern Myanmar (ca 99 Ma). Based on the available set of diagnostic characters, we interpret the specimen as a female of stem-group Luciolinae. The fossil possesses deeply impressed oval pits on the apices of antennomeres 3-11, representing specialized sensory organs likely involved in olfaction. The light organ near the abdominal apex of Flammarionella resembles that found in extant light-producing lucioline fireflies. The growing fossil record of lampyrids provides direct evidence that the stunning light displays of fireflies were already established by the late Mesozoic.

• Keywords
• Lampyridae, Mesozoic, bioluminescence, diversity,
• MeSH
• Biological Evolution MeSH
• Phylogeny MeSH
• Luminescence MeSH
• Fireflies * MeSH
• Arthropod Antennae MeSH
• Fossils * MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Myanmar MeSH

Rhagophthalmidae are a small beetle family known from the eastern Palaearctic and Oriental realms. Rhagophthalmidae are closely related to railroad worms (Phengodidae) and fireflies (Lampyridae) with which they share highly modified paedomorphic females and the ability to emit light. Currently, Rhagophthalmidae include 66 species classified in the following 12 genera: Bicladodrilus Pic, 1921 (two spp.), Bicladum Pic, 1921 (two spp.), Dioptoma Pascoe, 1860 (two spp.), Diplocladon Gorham, 1883 (two spp.), Dodecatoma Westwood, 1849 (eight spp.), Falsophrixothrix Pic, 1937 (six spp.), Haplocladon Gorham, 1883 (two spp.), Menghuoius Kawashima, 2000 (three spp.), Mimoochotyra Pic, 1937 (one sp.), Monodrilus Pic, 1921 (two spp. in two subgenera), Pseudothilmanus Pic, 1918 (two spp.), and Rhagophthalmus Motschulsky, 1854 (34 spp.). The replacement name Haplocladongorhami Kundrata, nom. nov. is proposed for Diplocladonhasseltii Gorham, 1883b (described in subgenus Haplocladon) which is preoccupied by Diplocladonhasseltii Gorham, 1883a. The genus Reductodrilus Pic, 1943 is tentatively placed in Lampyridae: Ototretinae. Lectotypes are designated for Pseudothilmanusalatus Pic, 1918 and P.marginalis Pic, 1918. Interestingly, in the eastern part of their distribution, Rhagophthalmidae have remained within the boundaries of the Sunda Shelf and the Philippines demarcated by the Wallace Line, which separates the Oriental and Australasian realms. This study is intended to be a first step towards a comprehensive revision of the group on both genus and species levels. Additionally, critical problems and prospects for rhagophthalmid research are briefly discussed.

• Keywords
• Catalogue, Drilidae, Lampyridae, Oriental Region, Phengodidae, classification, neoteny,
• Publication type
• Journal Article MeSH

We understand very little about the timing and origins of bioluminescence, particularly as a predator avoidance strategy. Understanding the timing of its origins, however, can help elucidate the evolution of this ecologically important signal. Using fireflies, a prevalent bioluminescent group where bioluminescence primarily functions as aposematic and sexual signals, we explore the origins of this signal in the context of their potential predators. Divergence time estimations were performed using genomic-scale datasets providing a robust estimate for the origin of firefly bioluminescence as both a terrestrial and as an aerial signal. Our results recover the origin of terrestrial beetle bioluminescence at 141.17 (122.63-161.17) Ma and firefly aerial bioluminescence at 133.18 (117.86-152.47) Ma using a large dataset focused on Lampyridae; and terrestrial bioluminescence at 148.03 (130.12-166.80) Ma, with the age of aerial bioluminescence at 104.97 (99.00-120.90) Ma using a complementary Elateroidea dataset. These ages pre-date the origins of all known extant aerial predators (i.e. bats and birds) and support much older terrestrial predators (assassin bugs, frogs, ground beetles, lizards, snakes, hunting spiders and harvestmen) as the drivers of terrestrial bioluminescence in beetles. These ages also support the hypothesis that sexual signalling was probably the original function of this signal in aerial fireflies.

• Keywords
• Lampyridae, aposematism, divergence time estimation, phylogeny, predation,
• MeSH
• Coleoptera * MeSH
• Chiroptera * MeSH
• Phylogeny MeSH
• Genomics MeSH
• Fireflies MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Paedomorphosis is a heterochronic syndrome in which adult individuals display features of their immature forms. In beetles, this phenomenon occurs widely in the superfamily Elateroidea, including the net-winged beetles (Lycidae), and, due to the usual flightlessness of paedomorphic females, it is hypothesized to cause speciation rates higher than in non-paedomorphic lineages. However, some fossils of paedomorphic lycids do not support this with palaeobiological data. Discovery of new Lycidae fossils attributed to the West Indian extant paedomorphic genus Cessator Kazantsev in the Dominican amber also suggests morphological stasis within this genus in the Greater Antilles. We describe Cessator anachronicus Ferreira and Ivie, sp. nov. based on adult males, as well as the first ever recorded fossil net-winged beetle larva of the same genus. We propose that the relatively young age of the studied fossils combined with the stable conditions in the forest floor of the Greater Antilles through the last tens of million years could explain the exceptionally conserved morphology in the net-winged beetles affected by the paedomorphic syndrome.

• MeSH
• Coleoptera * anatomy & histology   MeSH
• Amber * MeSH
• Forests MeSH
• Fossils MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Dominican Republic MeSH
• Names of Substances
• Amber * MeSH

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.

• Keywords
• CAT-GTR, Coleoptera, classification, diversification, phylogenomics, substitution modelling,
• Publication type
• Journal Article MeSH

We here report a new elateroid, Anoeuma lawrencei Li, Kundrata and Cai gen. et sp. nov., from mid-Cretaceous Burmese amber. Though superficially similar to some soft-bodied archostematans, Anoeuma could be firmly placed in the polyphagan superfamily Elateroidea based on the hind wing venation. Detailed morphological comparisons between extant elateroids and the Cretaceous fossils suggest that the unique character combination does not fit with confidence into any existing soft-bodied elateroid group, although some characters indicate possible relationships between Anoeuma and Omalisinae. Our discovery of this new lineage further demonstrates the past diversity and morphological disparity of soft-bodied elateroids.

• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

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.

• Keywords
• Elateridae, Lampyridae, Phengodidae, Rhagophthalmidae, Sinopyrophoridae, anchored hybrid enrichment, baitset, classification, four-cluster likelihood mapping, phylogenomics,
• Publication type
• Journal Article MeSH

The Elateridae (click-beetles) are the largest family in Elateroidea; however, their relationships, systematics and classification remain unclear. Our understanding of the origin, evolution, palaeodiversity and palaeobiogeography of Elateridae, as well as reconstruction of a reliable time-calibrated phylogeny for the group, are hampered by the lack of detailed knowledge of their fossil record. In this study, we summarize the current knowledge on all described fossil species in Elateridae, including their type material, geographic origin, age, bibliography and remarks on their systematic placement. Altogether, 261 fossil species classified in 99 genera and nine subfamilies are currently listed in this family. The Mesozoic click-beetle diversity includes 143 species, with most of them described from the Jurassic Karatau, and 118 described species are known from the Cenozoic deposits, mainly from the Eocene North American Florissant Formation and European Baltic amber. Available data on the described past diversity of Elateridae suggest that almost all fossil lineages in this group are in urgent need of revision and numerous Mesozoic species might belong to different families. Our study is intended to serve as a comprehensive basis for all subsequent research focused on the click-beetle fossil record.

• Keywords
• Cenozoic, Eucnemidae, Mesozoic, catalogue, classification, click-beetles, evolution, palaeodiversity, systematics,
• Publication type
• Journal Article MeSH