Jacek Szwedo

The earliest known holometabolous insects

The Eumetabola (Endopterygota (also known as Holometabola) plus Paraneoptera) have the highest number of species of any clade, and greatly contribute to animal species biodiversity. The palaeoecological circumstances that favoured their emergence and success remain an intriguing question. Recent molecular phylogenetic analyses have suggested a wide range of dates for the initial appearance of the Holometabola, from the Middle Devonian epoch (391 million years (Myr) ago) to the Late Pennsylvanian epoch (311 Myr ago), and Hemiptera (310 Myr ago). Palaeoenvironments greatly changed over these periods, with global cooling and increasing complexity of green forests. The Pennsylvanian-period crown-eumetabolan fossil record remains notably incomplete, particularly as several fossils have been erroneously considered to be stem Holometabola (Supplementary Information); the earliest definitive beetles are from the start of the Permian period. The emergence of the hymenopterids, sister group to other Holometabola, is dated between 350 and 309 Myr ago, incongruent with their current earliest record (Middle Triassic epoch). Here we describe five fossils— a Gzhelian-age stem coleopterid, a holometabolous larva of uncertain ordinal affinity, a stem hymenopterid, and early Hemiptera and Psocodea, all from the Moscovian age—and reveal a notable penecontemporaneous breadth of early eumetabolan insects. These discoveries are more congruent with current hypotheses of clade divergence. Eumetabola experienced episodes of diversification during the Bashkirian–Moscovian and the Kasimovian–Gzhelian ages. This cladogenetic activity is perhaps related to notable episodes of drying resulting from glaciations, leading to the eventual demise in Euramerica of coal-swamp ecosystems, evidenced by floral turnover during this interval. These ancient species were of very small size, living in the shadow of Palaeozoic-era ‘giant’ insects. Although these discoveries reveal unexpected Pennsylvanian eumetabolan diversity, the lineage radiated more successfully only after the mass extinctions at the end of the Permian period, giving rise to the familiar crown groups of their respective clades.

Traits and evolution of wing venation pattern in paraneopteran insects

Two different patterns of wing venation are currently supposed to be present in each of the three orders of Paraneoptera. This is unlikely compared with the situation in other insects where only one pattern exists per order. We propose for all Paraneoptera a new and unique interpretation of wing venation pattern, assuming that the convex cubitus anterior gets fused with the common stem of median and radial veins at or very near to wing base, after separation from concave cubitus posterior, and re‐emerges more distally from R + M stem. Thereafter, the vein between concave cubitus posterior and CuA is a specialized crossvein called “cua‐cup,” proximally concave and distally convex. We show that despite some variations, that is, cua‐cup can vary from absent to hypertrophic; CuA can re‐emerge together with M or not, or even completely disappear, this new interpretation explains all situations among all fossil and recent paraneopteran lineages. We propose that the characters “CuA fused in a common stem with R and M”and “presence of specialized crossvein cua‐cup” are venation apomorphies that support the monophyly of the Paraneoptera. In the light of these characters, we reinterpret several Palaeozoic and early Mesozoic fossils that were ascribed to Paraneoptera, and confirm the attribution of several to this superorder as well as possible attribution of Zygopsocidae (Zygopsocus permianus Tillyard, 1935) as oldest Psocodea. We discuss the situation in extinct Hypoperlida and Miomoptera, suggesting that both orders could well be polyphyletic, with taxa related to Archaeorthoptera, Paraneoptera, or even Holometabola. The Carboniferous Protoprosbolidae is resurrected and retransferred into the Paraneoptera. The genus Lithoscytina is restored. The miomopteran Eodelopterum priscum Schmidt, 1962 is newly revised and considered as a fern pinnule. In addition, the new paraneopteran Bruayaphis oudardi gen. nov. et sp. nov. is described fromthe Upper Carboniferous of France (see Supporting Information). J. Morphol., 2012.

From micropterism to hyperpterism: recognition strategy and standardized homology-driven terminology of the forewing venation patterns in planthoppers (Hemiptera: Fulgoromorpha)

Abstract Following recent advances in the morphological interpretations of the tegmen basal cell margins in the Paraneoptera, a standardized and homology-driven groundplan terminology for tegmina types, structures and vein patterns in Hemiptera Fulgoromorpha, including fossils, is proposed. Each term is listed with a morphological definition, compared and linked to the main systems of planthopper forewing description that have been reviewed. The importance of a standardized and homology-driven terminology is stressed to enhance the quality of data in taxonomic descriptions and to strengthen phylogenetic morphological analysis results. When the interpretation of the origin of vein branches is render difficult, a three-step strategy for pattern recognition of the vein is proposed based on two principles: (1) vein forks are more informative than topology of the vein branches: a search for homologous areas, the nodal cells in particular, must first guide the recognition rather the number of branches of a vein, and (2) minimum of ad hoc evolutionary events should be invoked in the understanding of a modified vein pattern. Examples of some conflicting interpretations of venation patterns in planthoppers are discussed within different families for both extant and extinct taxa. For the first time, the concept of brachypterism is defined in a non-relative way independently from other structures, and the new one of hyperpterism is proposed; a reporting system is proposed for each of them.

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

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.

The flies (Diptera) say that amber from the Gulf of Gdańsk, Bitterfeld and Rovno is the same Baltic amber

ABSTRACT Amber and its inclusions have been studied for over 200 years. Particular reverence was accorded the amber from the deposits around the Gulf of Gdańsk. As knowledge of amber increased, the problem of distinguishing amber from the various deposits along the Baltic Sea coast, but also in Germany, Belarus and Ukraine arose. Here we discuss the species composition of biting midges (Ceratopogonidae) from amber derived from different deposits, and discuss the use of regional names for Baltic amber yielding inclusions from the same taphocoenosis but of different geographical origin.

The oldest aphid insect from the Middle Triassic of the Vosges, France

A new family Vosegidae is described for Vosegus triassicus gen. et sp. nov. from the Anisian (early Middle Triassic) Grès à Voltzia Formation of the Vosges (north-eastern France). This is the oldest Aphidomorpha presenting the combination of characters as: elongate and tapered pterostigma with straight posterior margin, thick common stem of veins Sc+R+(M)+CuA, arcuate RP separated well basad of pterostigma base, three-branched M with free base, CuA forked, veins not differentiated in their thickness. The morphological characters presented by Vosegus are spread among the different extinct and extant lineages of Aphidomorpha, but the combination presented is unique. The relationships of this new family to other Triassic Sternorrhyncha are discussed, concluding its placement in Aphidomorpha: Triassoaphidoidea. The specificity of Grès à Voltzia fossil site in respect to early evolution of aphids is presented, with two competing explanations for size diminution, considering the Early Triassic biotic recovery versus the correlation between early aphid diversification and the exploitation of new niches, new host plants and habitats. This new finding increases the taxonomic diversity of the Grès à Voltzia fauna, expanding our knowledge of Early Triassic Aphidomorpha diversity and evolution.

Bacterial symbionts of the leafhopper Evacanthus interruptus (Linnaeus, 1758) (Insecta, Hemiptera, Cicadellidae: Evacanthinae).

Plant sap-feeding hemipterans harbor obligate symbiotic microorganisms which are responsible for the synthesis of amino acids missing in their diet. In this study, we characterized the obligate symbionts hosted in the body of the xylem-feeding leafhopper Evacanthus interruptus (Cicadellidae: Evacanthinae: Evacanthini) by means of histological, ultrastructural and molecular methods. We observed that E. interruptus is associated with two types of symbiotic microorganisms: bacterium ‘Candidatus Sulcia muelleri’ (Bacteroidetes) and betaproteobacterium that is closely related to symbionts which reside in two other Cicadellidae representatives: Pagaronia tredecimpunctata (Evacanthinae: Pagaronini) and Hylaius oregonensis (Bathysmatophorinae: Bathysmatophorini). Both symbionts are harbored in their own bacteriocytes which are localized between the body wall and ovaries. In E. interruptus, both Sulcia and betaproteobacterial symbionts are transovarially transmitted from one generation to the next. In the mature female, symbionts leave the bacteriocytes and gather around the posterior pole of the terminal oocytes. Then, they gradually pass through the cytoplasm of follicular cells surrounding the posterior pole of the oocyte and enter the space between them and the oocyte. The bacteria accumulate in the deep depression of the oolemma and form a characteristic ‘symbiont ball’. In the light of the results obtained, the phylogenetic relationships within modern Cicadomorpha and some Cicadellidae subfamilies are discussed.

Rooting down the aphid's tree – the oldest record of the Aphidomorpha lineage from Palaeozoic (Insecta: Hemiptera)

The new genus and species Lutevanaphis permiana gen.n. et sp.n., represents the oldest Aphidomorpha, new superfamily Lutevanaphidoidea superfam.n. and new family Lutevanaphididae. This taxon is described from the Middle Permian of the Lodève Basin, southern France. The presence of very small Aphidomorpha in the Middle Permian contradicts the hypothesis of the ‘Lilliput effect’ that is presumed to have affected the insect fauna during the Early to Middle Triassic, after the end‐Permian crisis. Very small insects were present well before the end of the Permian; their relative rarity is attributable probably to taphonomic biases.

First discovery of Neazoniidae (Insecta, Hemiptera, Fulgoromorpha) in the Early Cretaceous amber of Archingeay, SW France

Szwedo J. 2009. — First discovery of Neazoniidae (Insecta, Hemiptera, Fulgoromorpha) in the Early Cretaceous amber of Archingeay, SW France. Geodiversitas 31 (1) : 105-116. ABSTRACT The extinct genus and species of planthopper family Neazoniidae, Akmazeina santonorum n. gen., n. sp., are described. This is the first record of the family in the Lower Cretaceous French amber of Archingeay. The new genus differs from Neazonia Szwedo, 2007 in subtriangular vertex, wider trigons; sensory pits only in upper portion of frons, fused submedian carinae, diverging only in upper portion of frons, slightly elevated disc of pronotum, delimited by semicircular carinae, hind tibia with distinct, knee lateral tooth. The phylogenetic relationships of Neazoniidae and some other planthoppers families as well as their ecological affinities are discussed.