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

Was There a Cambrian Explosion on Land? The Case of Arthropod Terrestrialization

Arthropods, the most diverse form of macroscopic life in the history of the Earth, originated in the sea. Since the early Cambrian, at least ~518 million years ago, these animals have dominated the oceans of the world. By the Silurian-Devonian, the fossil record attests to arthropods becoming the first animals to colonize land, However, a growing body of molecular dating and palaeontological evidence suggests that the three major terrestrial arthropod groups (myriapods, hexapods, and arachnids), as well as vascular plants, may have invaded land as early as the Cambrian-Ordovician. These dates precede the oldest fossil evidence of those groups and suggest an unrecorded continental 'Cambrian explosion' a hundred million years prior to the formation of early complex terrestrial ecosystems in the Silurian-Devonian. We review the palaeontological, phylogenomic, and molecular clock evidence pertaining to the proposed Cambrian terrestrialization of the arthropods. We argue that despite the challenges posed by incomplete preservation and the scarcity of early Palaeozoic terrestrial deposits, the discrepancy between molecular clock estimates and the fossil record is narrower than is often claimed. We discuss strategies for closing the gap between molecular clock estimates and fossil data in the evolution of early ecosystems on lan

Integrated phylogenomic and fossil evidence of stick and leaf insects (Phasmatodea) reveal a Permian-Triassic co-origination with insectivores

Stick and leaf insects (Phasmatodea) are a distinctive insect order whose members are characterised by mimicking various plant tissues such as twigs, foliage, and bark. Unfortunately, the phylogenetic relationships among phasmatodean subfamilies and the timescale of their evolution remain uncertain. Recent molecular clock analyses have suggested a Cretaceous-Palaeogene origin of crown Phasmatodea and a subsequent Cenozoic radiation, contrasting with fossil evidence. Here we analysed transcriptomic data from a broad diversity of phasmatodeans and, combined with the assembly of a new suite of fossil calibrations, we elucidate the evolutionary history of stick and leaf insects. Our results differ from recent studies in the position of the leaf insects (Phylliinae), which are recovered as sister to a clade comprising Clitumninae, Lancerocercata, Lonchodinae, Necrosciinae, and Xenophasmina. We recover a Permian to Triassic origin of crown Phasmatodea coinciding with the radiation of early insectivorous parareptiles, amphibians, and synapsids. Aschiphasmatinae and Neophasmatodea diverged in the Jurassic–Early Cretaceous. A second spur in origination occurred in the Late Cretaceous, coinciding with the Cretaceous Terrestrial Revolution, and was likely driven by visual predators such as stem birds (Enantiornithes) and the radiation of angiosperms

Fleas are parasitic scorpionflies

Tihelka, Erik, Giacomelli, Mattia, Huang, Di-Ying, Pisani, Davide, Donoghue, Philip C. J., Cai, Chen-Yang (2020): Fleas are parasitic scorpionflies. Palaeoentomology 3 (6): 641-653, DOI: 10.11646/palaeoentomology.3.6.1

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

Mesozoic Notocupes revealed as the sister group of Cupedidae (Coleoptera: Archostemata)

Despite encompassing only about 50 extant species, beetles of the suborder Archostemata have a rich fossil history, being known from the Permian and dominating coleopteran assemblages in the Mesozoic before declining in richness towards the Late Cretaceous. Given the limited diversity of extant archostematans, fossils provide a valuable line of evidence for reconstructing the relationships among its constituent families. Here we re-evaluate the phylogenetic position of the Triassic–Cretaceous genus Notocupes, the most species-rich archostematan taxon in the fossil record. Exquisitely preserved fossils from the Middle Jurassic Haifanggou Formation (Daohugou; ~165 Ma) and mid-Cretaceous amber (~99 Ma) reveal critical differences from Ommatidae in the presence of separated procoxae and overlapping abdominal ventrites. Our analyses confirm that Notocupes is not a member of Ommatidae, but is closely related to Cupedidae. Our fossils reveal that Notocupes possessed unique adaptations for protecting their appendages, such as unusual dorsal pronotal grooves for the reception of antennae and epipleural grooves for the reception of legs, shedding light on ecological interactions in Mesozoic saproxylic habitats. The high similarity between Jurassic and Cretaceous Notocupes provides an exceptional example of long-term morphological stasis, suggesting a consistent microhabitat for the group

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