Haichun Zhang

Brood care in a 100-million-year-old scale insect

Behavior of extinct organisms can be inferred only indirectly, but occasionally rare fossils document particular behaviors directly. Brood care, a remarkable behavior promoting the survival of the next generation, has evolved independently numerous times among animals including insects. However, fossil evidence of such a complex behavior is exceptionally scarce. Here, we report an ensign scale insect (Hemiptera: Ortheziidae), Wathondara kotejai gen. et sp. nov., from mid-Cretaceous Burmese amber, which preserves eggs within a wax ovisac, and several freshly hatched nymphs. The new fossil is the only Mesozoic record of an adult female scale insect. More importantly, our finding represents the earliest unequivocal direct evidence of brood care in the insect fossil record and demonstrates a remarkably conserved egg-brooding reproductive strategy within scale insects in stasis for nearly 100 million years. DOI: http://dx.doi.org/10.7554/eLife.05447.001

WIDESPREAD PYRITIZATION OF INSECTS IN THE EARLY CRETACEOUS JEHOL BIOTA

ABSTRACT The Early Cretaceous Jehol biota of China, preserved in lacustrine deposits, yields abundant well-preserved invertebrate and vertebrate fossils. However, the exact mode and nature of its extraordinary preservation remains unclear. Here we investigated the preservation of fossil insects from lacustrine successions at 12 Lower Cretaceous localities of China, and found that many insects in Jehol biota were preserved by pyrite (later pseudomorphed by iron oxide). These pyritized fossils were observed solely within lacustrine deposits with volcanogenic sediments. The pyritization of Jehol insects has been facilitated by the moderate sedimentation rate, anoxic bottom environment, abundant dissolved iron and sulfur compounds from frequent volcanic eruptions, and sediments low in organic carbon. In addition, the pyritization process has been evidently aided by microbial films, which may have been widespread in the Jehol paleolakes. Our result provides the first record of widespread pyritization of insects from the freshwater Jehol biota, and shows that pyritization is an important preservational pathway in lacustrine successions.

Early Cretaceous angiosperms and beetle evolution

The Coleoptera (beetles) constitute almost one–fourth of all known life-forms on earth. They are also among the most important pollinators of flowering plants, especially basal angiosperms. Beetle fossils are abundant, almost spanning the entire Early Cretaceous, and thus provide important clues to explore the co-evolutionary processes between beetles and angiosperms. We review the fossil record of some Early Cretaceous polyphagan beetles including Tenebrionoidea, Scarabaeoidea, Curculionoidea, and Chrysomeloidea. Both the fossil record and molecular analyses reveal that these four groups had already diversified during or before the Early Cretaceous, clearly before the initial rise of angiosperms to widespread floristic dominance. These four beetle groups are important pollinators of basal angiosperms today, suggesting that their ecological association with angiosperms probably formed as early as in the Early Cretaceous. With the description of additional well-preserved fossils and improvements in phylogenetic analyses, our knowledge of Mesozoic beetle–angiosperm mutualisms will greatly increase during the near future.

40Ar/39Ar age constraints on the Haifanggou and Lanqi formations: When did the first flowers bloom?

Abstract Well-preserved Mesozoic terrestrial fossils were discovered in the Haifanggou Formation and the overlying Lanqi Formation (or their correlative strata) in NE China. The recent discoveries of Schmeissneria sinensis and Xingxueanthus sinensis from the middle and upper Jurassic Haifanggou Formation provide evidence that the origin of angiosperms could be predate the Early Cretaceous. In addition to the finding of pre-Cretaceous angiosperms from the Haifanggou Formation, the overlying Lanqi Formation yields a rich and varied terrestrial flora. The high diversity and abundance of the palaeoflora from these formations provide a unique window to understand floral evolution and its diversification in the Mesozoic. Two tuff samples and one andesite sample collected from the Haifanggou and Lanqi formations near Beipiao City, Liaoning, NE China yield robust 40Ar/39Ar age results. Our 40Ar/39Ar age of 166.7 ± 1.0 Ma for plagioclases from one tuff interbedded in the fossiliferous horizons of the middle Haifanggou Formation provides accurate age calibration for the pre-Cretaceous angiosperms for the first time. Moreover, our age results for these fossil-bearing formations will improve our knowledge of the Jurassic environment in general, including the link between plants and atmospheric CO2. Supplementary material: Details of analysis procedures, Ar isotopic data corrected for blanks, mass discrimination, radioactive decay and J values are available at: http://www.geolsoc.org.uk/SUP18575.

A Diverse Paleobiota in Early Eocene Fushun Amber from China

Paleogene arthropod biotas have proved important for tracing the faunal turnover and intercontinental faunal interchange driven by climatic warming and geodynamic events [1-5]. Despite the large number of Paleogene fossil arthropods in Europe and North America [5-8], little is known about the typical Asian (Laurasia-originated) arthropod biota. Here, we report a unique amber biota (50-53 million years ago) from the Lower Eocene of Fushun in northeastern China, which fills a large biogeographic gap in Eurasia. Fushun amber is derived from cupressaceous trees, as determined by gas chromatography-mass spectrometry, infrared spectroscopy, and paleobotanical observations. Twenty-two orders and more than 80 families of arthropods have been reported so far, making it among the most diverse amber biotas. Our results reveal that an apparent radiation of ecological keystone insects, including eusocial, phytophagous, and parasitoid lineages, occurred at least during the Early Eocene Climatic Optimum. Some insect taxa have close phylogenetic affinities to those from coeval European ambers, showing a biotic interchange between the eastern and western margins of the Eurasian landmass during the Early Paleogene.

A TENTATIVE STUDY ON THE ULTRASTRUCTURE OF THE MIDDLE PERMIAN ACRITARCH MICRHYSTRIDIUM FROM WESTERN YUNNAN, CHINA

A preliminary study on the ultrastructure of Middle Permian AcritarchMicrhystridium from western Yunnan has been made using laser scanning confocal microscope (LSCM). Some quite new features about the texture and ultrastructure of this kind of Acritarch has been detected for the first time, which opens up a new application of this advanced technique to microfossil study.

The earliest known longhorn beetle (Cerambycidae: Prioninae) and implications for the early evolution of Chrysomeloidea

Mesozoic fossils of longhorn beetles, leaf beetles and other Chrysomeloidea are extremely rare, and little is known about the early evolutionary history of this extraordinarily diverse superfamily of beetles. Here we report the earliest known fossil cerambycid, Cretoprionus liutiaogouensis gen. et sp. nov., from the Lower Cretaceous Yixian Formation of China. C. liutiaogouensis bears several features characteristic of the extant subfamily Prioninae, including a large and robust body, absence of a stridulatory plate on the mesonotum, pseudotetramerous tarsi, mouthparts projecting forwards, and lateral carinae on the prothorax. It represents the only definite Mesozoic record of Cerambycidae, and extends the time of origin of the Prioninae as early as the Early Cretaceous. We incorporate two new calibration points as minimum constraints on the age of (1) Prioninae + Parandrinae and (2) Bruchinae using data from a recent molecular phylogenetic study of Chrysomeloidea, to reconstruct divergence times among the major lineages of Chrysomeloidea. Our analyses suggest that most chrysomeloid families appeared in the Jurassic and diversified over the course of the Cretaceous, a scenario consistent with the codiversification of Chrysomeloidea and their (predominantly) angiospermous hosts; however, the phylogeny of Chrysomeloidea remains incompletely resolved, and further elucidation of timing and patterns of chrysomeloid macroevolution will require additional study. http://zoobank.org/urn:lsid:zoobank.org:pub:0FF28F2E-026E-4408-9CF6-D61B6197548E

Middle Jurassic Praeaulacidae (Insecta: Hymenoptera: Evanioidea) of Inner Mongolia and Kazakhstan

Synopsis Sixteen new and one undetermined species within six genera, of which two are recognised as new, referable to Praeaulacidae are described from the Middle Jurassic Daohugou deposits of Ningcheng, Inner Mongolia, China. They are Praeaulacus orientalis sp.nov.,Praeaulacus daohugouen‐sis sp. nov., Praeaulacus exquisitus sp. nov., Praeaulacus scabratus sp. nov., Praeaulacus sculptus sp. nov., Praeaulacus robustus sp. nov., Praeaulacus afflatus sp. nov., Praeaulacon ningchengensis sp. nov., Praeaulacon elegantulus sp. nov., Aulacogastrinus insculptus sp. nov., Aulacogastrinus longaciculatus sp. nov., Aulacogastrinus hebeiensis sp. nov., Aulacogastrinus sp., Sinaulacogast‐rinus eucallus gen. et sp. nov., Eosaulacus giganteus gen. et sp. nov. and Eosaulacus granulatus gen. et sp. nov. within Praeaulacinae, and Anomopterella huangi sp. nov. within Anomopterellinae. In addition, a new species, Nevania karatau sp. nov., assigned to Nevaniinae is reported from the Late Jurassic Karabastau Formation of Karatau, southern Kazakhstan. A key to known taxa within Praeaulacinae and Anomopterellinae, respectively, is presented. The presence of five common genera between the Daohugou and Karatau faunas indicates a close relationship between the two regions. Both a high attachment of metasoma on propodeum and a quite high diversity in the Praeaulacidae in the Middle Jurassic indicate that the Evanioidea probably emerged as early as in the Early Jurassic. The Anomopterellinae were parasitic on xylophages like Praeaulacinae.

Debris-carrying camouflage among diverse lineages of Cretaceous insects

A diverse insect assemblage of exceptionally preserved debris carriers is reported from Cretaceous Burmese, French, and Lebanese ambers. Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.

THE OLDEST TENEBRIONOIDEA (COLEOPTERA) FROM THE MIDDLE JURASSIC OF CHINA

Abstract The Tenebrionoidea is among the most diverse group of beetles, but its fossil record is rare. A definitive oldest tenebrionoid beetle, Wuhua jurassica new genus new species, is described from the Middle Jurassic of Daohugou, China. It is tentatively placed as Family incertae sedis, and distinguished from others of Tenebrionoidea by the unusual combination of following characters: body convex; head strongly deflexed, not received into prothorax; antennae filiform; pygidium absent; tarsi simple and tarsal claws pectinate. This discovery extends the time of origin of Tenebrionoidea to the Middle Jurassic. Furthermore, the record of Mesozoic tenebrionoid beetles are summarized and discussed.