Mimicry in Cretaceous Bugs

This work is licensed under a Creative Commons Attribution 4.0 International License.Mimicry is ubiquitous in nature, yet understanding its origin and evolution is complicated by the scarcity of exceptional fossils that enable behavioral inferences about extinct animals. Here we report bizarre true bugs (Hemiptera) that closely resemble beetles (Coleoptera) from mid-Cretaceous amber. The unusual fossil bugs are described as Bersta vampirica gen. et sp. nov. and Bersta coleopteromorpha gen. et sp. nov. and are placed into a new family, Berstidae fam. nov. The specialized mouthparts of berstids indicate that they were predaceous on small arthropods. Their striking beetle-like appearance implies that they were either involved in defensive mimicry or mimicked beetles to attack unsuspecting prey. The latter would represent the first case of aggressive mimicry in the invertebrate fossil record. These findings enrich our understanding of the paleoecological associations and extinct behavioral strategies of Mesozoic insects.Strategic Priority Research Program of the Chinese Academy of Sciences (XDB26000000 and XDB18000000)National Natural Science Foundation of China (41672011 and 41688103)Second Tibetan Plateau Scientific Expedition and Research (2019QZKK0706

New cleroid beetles from the Middle–Late Jurassic of China

Four specimens of fossil beetles recorded from the Middle and Late Jurassic boundary beds of Inner Mongolia, China are assigned to the melyrid lineage of Cleroidea. Three of them are described as Sinomelyris praedecessor gen. et sp. nov. and constitute the earliest known representatives of the family Melyridae. The new species habitually resembles some extant beetles of the subfamily Melyrinae but it is distinctly smaller and possesses four elytral carinae, the pronotum without a pair of the dorsolateral carinae, and the tarsal claw simple. The fourth specimen Juraniscus majeri gen. et sp. nov., is classified as Cleroidea incertae sedis. The new species has the symmetrical antennomeres including three terminal ones, the tarsomeres 1–4 with the lobes, the tarsal claw simple, and the aedeagus with the separated parameres. It is considered to be a member of the melyrid lineage and its relations to the relevant families Mauroniscidae, Rhadalidae, Dasytidae, and Malachiidae are discussed. A complete list of fossil species in the melyrid lineage described to date is provided

A specialized prey-capture apparatus in mid-Cretaceous rove beetles

Cai et al. report specialized prey-capture structures in two species of the stenine rove beetles from mid-Cretaceous Burmese amber. The discovery provides critical information about the origin and early evolution of both the novel predatory structure and of the subfamily Steninae (Coleoptera: Staphylinidae)

Mastigocoleidae fam. nov., a New Mesozoic Beetle Family and the Early Evolution of Dryopoidea (Coleoptera)

With some 3,700 described species, Dryopoidea are a moderately diverse superfamily of beetles whose position within basal Polyphaga has been historically difficult to elucidate. Members of most extant dryopoid families are set apart from the majority of other polyphagans by their association with aquatic habitats, but little is known about the origin of these derived life habits and the phylogeny of the superfamily. Here we describe Mastigocoleidae Tihelka, Jäch, Kundrata & Cai fam. nov., a new family of Mesozoic dryopoids represented by fossils from the Cretaceous Yixian Formation in northeastern China (undescribed species; ~125 Ma), Crato Formation in northeastern Brazil (Mastigocoleus rhinoceros Tihelka & Cai gen. et sp. nov.; ~113 Ma), and amber from northern Myanmar (Mastigocoleus resinicola Tihelka & Cai gen. et sp. nov. and Cretaceocoleus saetosus Tihelka, Kundrata & Cai gen. et sp. nov.; ~99 Ma). Integrating the findings of recent molecular and morphological phylogenetic analyses, we recover Mastigocoleidae as an early-diverging dryopoid clade sister to the families Lutrochidae and Dryopidae, or less likely as a group of putative stem-dryopoids. Mastigocoleidae are most distinctly separated from all other dryopoid families by their whip-like antennae, with 11 antennomeres, reaching to the pronotal base, and with the scape broadest and longest, a short pedicel, and antennomeres II-XI more or less distinctively gradually tapering toward the apex. Mastigocoleidae indicate that the last common ancestor of Dryopoidea was likely terrestrial in the adult stage, and document character acquisitions associated with a specialization for aquatic life

Integrated phylogenomics and fossil data illuminate the evolution of beetles

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 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., 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 Paleozoic 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