Arthropods were the first known animals to colonise land habitats, with myriapods and arachnids having done so at least by the Silurian. Much later, several lineages of Pancrustacea (hexapods and the paraphyletic crustaceans) also ventured onto land; the hexapods by the Early Devonian, and later at least four other groups of crustaceans, namely isopods, amphipods, ostracods and decapods, most of which generally colonised the continental water bodies. All faced a series of challenges (in particular: gas exchange; desiccation; reproduction; osmoregulation; and exposure to ultraviolet radiation), resulting in many morphological, physiological and ecological adaptations. Nonetheless, whether they reached land via saltwater or freshwater remains poorly documented, mainly because relevant localities are few. The Famennian (Late Devonian) Strud locality in Belgium provided an exceptional source of information on early aquatic continental ecosystems and their plant, vertebrate and arthropod colonisers at a crucial step in the terrestrialisation process. Here, we review and update its crustacean fauna, which inhabited floodplain and temporary pool waters. New anatomical details of the notostracan Strudops goldenbergi Lagebro et al., 2015, as well as a new genus and species of spinicaudatan, are described. We also discuss the ecology of this unique, early continental ecosystem and the insights it gives into the terrestrialisation process.

Two new species of Schramocaris from the Viséan, Lower Carboniferous of Scotland and eastern Canada extend the range and distribution of this crustacean along the northwestern coast of the Rheic Ocean. New species from Glencartholm, southern Scotland and Upperton, New Brunswick, Canada represents the first recognised occurrence of this genus in Scotland and Canada. The Scottish species is here named S. clarksoni; it lacks the rugosity of the carinae of Schramocaris gilljonesorum, but has the same relative position of the carinae, as well as similar characteristics of the pleon, such as the relative lengths of the somites and the shape of the telson. The Canadian species is named Schramocaris matthewi on the basis of the papillations on the cuticle and robust second carinae of the carapace. The deposits at both these localities are that of a shallow marine argillaceous environment, although the Glencartholm deposit contains more lime. Schramocaris has previously only been known from the Avon Group (Hastarian) of the Forest of Dean, England.

New palaeodictyopterans, Vernooijia sassoonae gen. et sp. nov. (Breyeriidae) and Mazonopterumcooperi sp. nov. (Homoiopteridae) are described from the Middle Pennsylvanian (Westphalian D/Late Asturian) of Writhlington, near Radstock (UK). Based on the re-examination of venation in Breyeriaharlemensis, we propose the transfer of this species to the genus Vernooijia as V.harlemensis (Brauckmann & Gröning, 1996) comb. nov. We report the first record of Homaloneura sp. (Spilapteridae) from the Langsettian to Duckmantian of Coseley, Staffordshire. Additionally, we report a fragmentary wing from the Middle Pennsylvanian (late Westphalian D/early Cantabrian) of the Forest of Dean, Gloucestershire, tentatively belonging to the Lycocercidae. Our re-examination of a putative blattodean nymph described by Rolfe (1967) allows re-assignment to Palaeodictyoptera, as it has well-developed wing pads with a corrugated pattern of probably original tracheation and lacunal channels, identified as presumably nymphal exuvia of Idoptilus sp. Surprisingly, our study reveals the presence of three triangular caudal appendages bearing prominent lateral lamellae emerging from the terminal abdominal segment, previously unknown in other nymphs of Palaeodictyoptera. We assume that these lamellae were originally covered with dense setae and possibly represent modified caudal appendages in the form of tracheal gills, as known in the nymphs of damselflies (Odonata: Zygoptera). Thus, the scenario of a possible aquatic lifestyle for nymphs of at least some members of Palaeodictyoptera, as considered by Brongniart (1885, 1893) and Handlirsch (1906), cannot be definitely excluded.

This paper outlines and discusses the fossil record of the Hemiptera – the fifth most diverse insect order. The diversity of these insects in comparison with the “Big Four” group is given, together with a short history of its classification. Updated information is presented about the fossil record of particular families, with a brief analysis. The main evolutionary traits of the major Hemiptera lineages are briefly described. The influence of biotic interactions with endosymbionts, shaping the evolution of the hemipterans as well as abiotic events and major global changes, is disputed. The innovations and perils of the evolutionary history of the Hemiptera are presented.

Dermaptera (earwigs) are described from the Triassic of Australia and England, and from the Jurassic and Cretaceous of England. Phanerogramma heeri (Giebel) is transferred from Coleoptera and it and Brevicula gradus Whalley are re-described. Seven new taxa are named based on tegmina: Phanerogramma australis sp. nov. and P. dunstani sp. nov. from the Late Triassic of Australia; P. gouldsbroughi sp. nov. from the Triassic/Jurassic of England; Brevicula maculata sp. nov. and Trivenapteron moorei gen. et sp. nov. from the Early Jurassic of England; and Dimapteron corami gen et sp. nov. and Valdopteron woodi gen. et sp. nov. from the Early Cretaceous of England. Phanerogramma, Dimapteron and Valdopteron are tentatively placed in the family Dermapteridae, and Trivenapteron is incertae sedis. Most of the specimens of Phanerogramma heeri are from the Brodie Collection and labelled ‘Lower Lias'; however, some were collected from the underlying Penarth Group, thus this species spans the Triassic/Jurassic boundary. The palaeobiogeography of the Late Triassic and Early Jurassic of England is discussed.

A new family, Worcestobiidae fam. nov., is established for two Triassic fossil species of Mecoptera removed from the family Orthophlebiidae: Orthophlebia gigantea Tillyard, 1933 and O. haradai Ueda, 1991. A new genus, Worcestobia gen. nov., is erected and both species are transferred to this genus. The new taxa were established as a result of ongoing taxonomic work on Orthophlebiidae, one of the most problematic families within fossil Mecoptera, considered to be a paraphyletic group of species.

The family Austropanorpidae (Mecoptera) was described by Willmann in 1977 from the Eocene of Australia, based on one genus and species, Austropanorpa australis Riek, 1952. During a restudy of the collection of the Paleontological Institute, Russian Academy of Sciences in Moscow, a second and much older representative of this family was found. This specimen, described as Orthophlebia martynovae Sukatsheva, 1985 from Siberia (Russia), was considered until now to be a member of family Orthophlebiidae. We transfer this species to the Austropanorpidae, extending the age of this family back to the Early Jurassic. An updated diagnoses of the family Austropanorpidae and genus Austropanorpa are presented here.

The genus Orthobittacus was established by Willmann (1989) and is characterised by a long Sc vein and the unusually developed medial sector for the Bittacidae. Four Jurassic species have been described in this genus to date: O. abshiricus (Martynova, 1951) from Kirgizia; O.desacuminatus (Bode, 1953) from Braunschweig (Germany); O. polymitus Novokshonov, 1996 from Karatau (Kazakhstan); and O. maculosus Liu, Shih, Bashkuev & Ren, 2016 from the Jiulongshan Formation of Daohugou (China). The fifth congeneric and second species from China, O. suni sp. nov., is described herein. The importance of the genus Orthobittacus for the phylogeny of Bittacidae, as the most plesiomorphic genus, is discussed.

Twelve specimens of early Toarcian Mecoptera and Diptera from the vicinity of Wolfsburg were investigated for the present study. The material was found during house building activities in the 1980s at the locality Große Kley in Mörse, an urban district of the city of Wolfsburg, Lower Saxony, Germany. The specimens were found in calcareous nodules of the Harpoceras falciferum Zone that occur within the Liassic black shales (Posidonia shale). Six specimens of Mecoptera, five belonging to the family Orthophlebiidae and one belonging to the Bittacidae, and six representatives of the following Diptera families were identified: Ptychopteridae, Limoniidae, Anisopodidae and the superfamily Mycetophiloidea. The fossil fauna of Wolfsburg is similar to that of other early Toarcian sites in Germany, described by Handlirsch (1906, 1939), Bode (1905, 1953) and Ansorge (1996) from Braunschweig, Dobbertin and Grimmen. Two new species are described, Mesorhyphusulrichi sp. nov. (Anisopodidae) and Archipleciomima germanica sp. nov. (Mycetophiloidea).

Here is described the oldest known species of Trichoceridae, from Sogyuty, near lake Issyk-Kul (Kyrgyzstan; Lower Jurassic: Sinemurian). The species is placed in the genus Mailotrichocera Kalugina, 1985in Kalugina & Kovalev (1985), based on isolated wings. The venation of fossil and Recent Trichoceridae is discussed in terms of the biomechanical properties of the wings. The wings of the stem lineage of the family, characterised by a short subcostal vein, also had a larger distal supporting sector than younger lineages, including Recent representatives.

Five orthopteran specimens from the uppermost Middle–lowermost Upper Jurassic of Daohugou, Inner Mongolia, China are described and attributed to the genus Sigmaboilus Fang, Zhang & Wang, 2007 (Prophalangopsidae); and a new species, S. calophlebius sp. nov., is established herein. The diagnostic characters for Sigmaboilus are revised and a key to species of Sigmaboilus, based on male forewings, is provided. Intraspecific variation in forewings of this genus is also discussed.

Abundant insect fossils have been recorded from the Lower Cretaceous of the Jiuquan Basin, but very few odonatans have been recorded. In this paper, a new damsel-dragonfly, Cretastenophlebia jiuquanensis sp. nov., is described from the Lower Cretaceous Zhonggou Formation in the Hanxiagou outcrop, Jiuquan Basin, northwestern China. This is the second species of the genus Cretastenophlebia Fleck et al., 2003. Cretastenophlebia jiuquanensis sp. nov. differs from Cretastenophlebia mongolica Fleck et al., 2003 in the presence of a broad discoidal triangle, a basally straight IR1 and less cells along the posterior wing margin between IR2 and RP2. Cretastenophlebia has been previously reported from the Lower Cretaceous of Bon-Tsagaan, central Mongolia. The new discovery expands the record of Cretastenophlebia to the Jiuquan Basin in Albian.

The Family Orthophlebiidae ranges from the Middle Triassic to the Early Cretaceous. The Wealden Mecoptera have added to our knowledge of the Mecoptera from the Early Cretaceous of southern England, but have been comparatively little studied. Here we present the description of the first orthophlebiid from the Wealden of England. Mesopanorpa brooksorum sp. nov. from England is the earliest Cretaceous representative of this genus.

One new genus and four new species of Chrysopidae are described from the Lower Cretaceous of Khasurty, Transbailakia (Russia): Mesypochrysa cannabina sp. nov.; M. naranica sp. nov.; Aberrantochrysa buryatica gen. & sp. nov.; and A. pulchella gen. & sp. nov. The abundance of Chrysopidae in Mesozoic localities is discussed.

Fossils in amber are a particularly important and unique palaeobiological resource. Amber is best known for preserving exceptionally life-like fossils, including microscopic anatomical details, but this fidelity of preservation is an end-member of a wide spectrum of preservation quality. Many amber sites only preserve cuticle or hollow moulds, and most amber sites have no fossils at all. The taphonomic processes that control this range in preservation are essentially unknown. Here, we review the relationship between amber groups and fossil preservation, based on published data, to determine whether there is a correlation between resin type and aspects of preservation quality. We found that ambers of different chemistry demonstrated statistically significant differences in the preservational quality and the propensity of a site to contain fossils. This indicates that resin chemistry does influence preservational variation; however, there is also evidence that resin chemistry alone cannot explain all the variation. To effectively assess the impact of this (and other) variables on fossilisation in amber, and therefore biases in the amber fossil record, a more comprehensive sampling of bioinclusions in amber, coupled with rigorous taphonomic experimentation, is required.

Lebanese amber contains a diverse biota from the Lower Cretaceous, and more than 150 families of arthropods have been reported as inclusions. Amongst these, caddisflies (Trichoptera) are very scarce inclusions, consisting of a few indeterminate fragments and only two inclusions that permit clear descriptions of new species. We describe the first two Trichoptera species from Lebanese amber, belonging respectively to Dipseudopsidae (Phylocentropus succinolebanensis n. sp.) and Ecnomidae (Ecnomus cretacia n. sp.). Previously, the oldest fossil representatives of both families were known from the Upper Cretaceous amber of New Jersey for Dipseudopsidae and from the Eocene Baltic amber for Ecnomidae.

Biting midges (Diptera: Ceratopogonidae) are a large family of flies that commononly appear in Lower Cretaceous to Miocene strata, with over 280 fossil species (4.3 % of the family), belonging to 49 genera (26 extant; 23 extinct). Morphological characters used in the identification of fossil genera and species are identical to those used in studies of extant Ceratopogonidae and, as a result, their potential indicative value is reliable. Two relictual extant genera, Leptoconops and Austroconops, reported from Lower Cretaceous Lebanese amber, are at least 125 million years old. Certain ceratopogonid genera are indicative for the Lower Cretaceous, Upper Cretaceous, Eocene or Miocene. A morphological character indicative for the Upper Cretaceous and Cenozoic is macrotrichia on the wing membrane of adults. Indicator species and genera are reviewed for all amber deposits. Eocene Baltic amber contains the best known fauna of biting midges, with 109 named species. Some genera are indicative of aquatic and semiaquatic habitats (predaceous genera, subfamily Ceratopogoninae), forests with rotting trees (Forcipomyia), sandy sea shore habitats (Leptoconops), a cold boreal climate (Ceratopogon) or warm climates (Nannohelea, Austroconops, Leptoconops, Meunierohelea, Metahelea). Females require a protein-rich meal and are well known for feeding on the blood of vertebrates, but many feed on other things, so this information can help with the interpretation of palaeoenvironments. Washingtonhelea taimyrica Szadziewski, 1996, described from Siberian amber, is transferred to the fossil genus Palaeobrachypogon: P.taimyricus (Szadziewski, 1996), comb. nov. For Serromyia alphea, mistakenly redescribed and illustrated from Eocene Bitterfeld amber (= Baltic amber) by Szadziewski (1993), a new name – Serromyiaerrata Szadziewski, nom. nov. – is proposed.

Helius spiralensis sp. nov., is a very peculiar species of the genus Helius (Diptera: Limoniidae), with a characteristic morphology of hypopygium not found in other representatives of this genus. This is the second Helius species described from Early Cretaceous Álava amber (Spain), and one of the oldest representatives of the genus.

Clavate (club-shaped) structures rimming mid-Cretaceous Burmese amber from Myanmar, previously misdiagnosed as fungal sporocarps, are shown to be domichnia (crypts) of martesiine bivalves (Pholadidae: Martesiinae). They are similar in form to Teredolites clavatus Leymerie, 1842 and Gastrochaenolites lapidicus Kelly & Bromley, 1984; however, the former identification is preferable, given that they are martesiine crypts in amber as opposed to a lithic substrate. Cross-cutting relationships between the clavate features and inclusions in the amber demonstrate that the features post-date hardening of the resin. The fills of the crypts are variable, including sand grade sediment of very fine to coarse sand grainsize, and sparry calcite cements. In some cases, the articulated valves of the pholadid bivalve responsible are visible inside the borings. However, one remarkable specimen contains two pairs of articulated shells ‘floating’ in amber, not associated with crypts; an observation that suggests that the resin was still liquid or soft when the bivalves were trapped in the resin. One individual is associated with an irregular sediment-filled feature and shows shell breakage. Formation of a solid rim around a liquid central volume has been documented in subaqueous bodies of resin in modern swamp forests, and argues for a close proximity between the amber-producing trees and a brackish water habitat for the bivalves. The presence of pyrite as thin films and crystal groups within Burmese amber is further consistent with such a depositional environment. Comparison of the size of pholadid body fossils with growth rates of modern equivalents allows the duration of boring activities to be estimated and suggests that small fossil pholadids in Burmese amber became trapped and died within 1–2 weeks of having settled on the resin. Larger examples present within well-formed domichnia formed in hardened resin. Since ‘hardground’ describes early lithified sediment as a substrate and ‘woodground’ describes wood as a substrate, the term ‘amberground’ is used here to described borings in an amber substrate.