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 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

Gondwanan elaterids, previously thought to be unrelated, include bioluminescent Campyloxenus earlier placed in bioluminescent Pyrophorinae. Genomic data suggest close relationships between Gondwanan groups. We maintain Morostomatinae and Hapatesinae and redefine Pityobiinae with Nearctic Pityobiini, Gondwanan Parablacini stat. nov., Campyloxenini stat. nov., and Tibionemini trib. nov. Their ancestors putatively underwent differentiation in Gondwana during the Cretaceous separation of southern continents. In contrast with their age, extant groups are species poor. Campyloxenus represents a recent origin of bioluminescence, no older than ∼53 my. Its large pronotal lanterns differ from Pyrophorini and resemble color patches of sympatric beetle co-mimics. This discovery highlights the fourth or fifth origin of bioluminescence in Elateroidea, alongside the lampyroid clade, click beetles Pyrophorini, Alampoides and Coctilelater in Anaissini (Pyrophorinae), and Balgus schnusei (Thylacosterninae). While our phylogenetic findings illuminate the phylogenetic aspects, the complete story awaits further field observations and in-depth genomic analyses of biochemical pathways used by bioluminescent elateroids.

• Keywords
• Entomology, evolutionary biology, phylogenetics,
• Publication type
• Journal Article 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