Group mating in Cretaceous water striders.

Fossilized mating insects are irreplaceable material for comprehending the evolution of the mating behaviours and life-history traits in the deep-time record of insects as well as the potential sexual conflict. However, cases of mating pairs are particularly rare in fossil insects, especially aquatic or semi-aquatic species. Here, we report the first fossil record of a group of water striders in copulation (including three pairs and a single adult male) based on fossils from the mid-Cretaceous of northern Myanmar. The new taxon, Burmogerris gen. nov., likely represents one of the oldest cases of insects related to the marine environment, such as billabongs formed by the tides. It exhibits conspicuous dimorphism associated with sexual conflict: the male is equipped with a specialized protibial comb as a grasping apparatus, likely representing an adaptation to overcome female resistance during struggles. The paired Burmogerris show smaller males riding on the backs of the females, seemingly recording a scene of copulatory struggles between the sexes. Our discovery reveals a mating system dominated by males and sheds light on the potential sexual conflicts of Burmogerris in the Cretaceous. It indicates the mating behaviour remained stable over long-term geological time in these water-walking insects.

An enigmatic Cretaceous beetle with possible affinity to Erotylidae (Coleoptera: Cucujiformia).

The morphology of beetles of the recently defined superfamilies Erotyloidea, Nitiduloidea and Cucujoidea is varied. Determining the systematic positions of Mesozoic fossils within these groups can often be challenging. Here we describe and illustrate a puzzling cucujiform beetle, Isocryptophilus exilipunctus Li & Cai gen. & sp. nov., based on an individual from mid-Cretaceous Burmese amber. While we cannot definitively pinpoint the exact phylogenetic position of Isocryptophilus, its possible affinity to Erotylidae is discussed in light of our phylogenetic analyses. A broader-sampled morphological matrix, coupled with a robust molecular phylogeny of these groups, will be promising for clarifying the systematic placement of the fossil.

The earliest fossil mosquito.

Female mosquitoes are among the most notorious blood-feeding insects, sometimes causing severe allergic responses or vectoring a variety of microbial pathogens.1,2 Hematophagy in insects is likely a feeding shift from plant fluids, with the piercing-sucking mouthparts serving as suitable exaptation for piercing vertebrates' skin. The origins of these habits are mired in an often-poor fossil record for many hematophagous lineages,3,4 particularly those of sufficient age, as to give insights into the paleoecological context in which blood feeding first appeared or even to arrive at gross estimates as to when such shifts have occurred. This is certainly the case for mosquitoes, a clade estimated molecularly to date back to the Jurassic.5 The known Mesozoic Culicidae are Late Cretaceous, assigned to the modern Anophelinae or to the extinct Burmaculicinae, sister to other Culicidae, all with mouthparts of a modern type. Here, we report the discovery, in Lower Cretaceous amber from Lebanon, of two conspecific male mosquitoes unexpectedly with piercing mouthparts, armed with denticulate sharp mandibles and laciniae. These male fossils were likely hematophagous. They represent a lineage that diverged earlier than Burmaculicinae, extending the definitive occurrence of the family into the Early Cretaceous and serving to narrow the ghost-lineage gap for mosquitoes.

Atypical 'long-tailed' cockroaches arose during Cretaceous in response to angiosperm terrestrial revolution.

Typical cockroaches are flat, broad, with large pronotum and wings covering the body. This conserved morphotype dates back to the Carboniferous, during which the ancestral cockroaches, or roachoids, originated. On the other hand, the ovipositor of cockroaches gradually reduced during the Mesozoic, coupled with a major shift of reproductive strategy. By the Cretaceous, long external ovipositors became rare, most cockroaches used very short or even hidden internal ovipositors to fabricate egg cases (oothecae), which is an innovation for egg protection. Here, we describe two cockroaches from mid-Cretaceous Myanmar amber: Ensiferoblatta oecanthoides gen. et sp. nov. (Ensiferoblattidae fam. nov.) and Proceroblatta colossea gen. et sp. nov. They are slim, elongate, fusiform, with longitudinal pronotum, and have long external ovipositors. The combination of these traits represents a unique morphotype, which resembles crickets and katydids (Ensifera) more than general cockroaches. Ensiferoblatta and Proceroblatta may be arboreal, feeding on and/or laying eggs into certain angiosperms that newly emerged. Their open habit causes latent impairment to viability, and may contribute to their extinction. These new taxa are the youngest members of the ancient, extinct group of cockroaches, namely Eoblattodea, which are characterized by long ovipositors. We speculate that the extinction of certain gymnosperm hosts almost ended the 200-My triumph of Eoblattodea. Despite an attempt to adapt to angiosperm hosts, Ensiferoblatta, Proceroblatta and suchlike cockroaches as an evolutionary dead end failed to save Eoblattodea from extinction. The lack of protection for eggs (maternal care in particular) might accelerate the extinction of Eoblattodea as a whole.

Sinoagetopanorpidae fam. nov., a New Family of Scorpionflies (Insecta, Mecoptera) from the Guadalupian of South China.

Mecoptera was in great abundance in the Permian, but little is known from China. A new family, Sinoagetopanorpidae fam. nov., is described and illustrated from the upper Guadalupian Yinping Formation at Yinping Mountain, Chaohu City, Anhui Province, China. Sinoagetopaorpa permiana Lin, Nel and Huang, 2010 was previously attributed to Permochoristidae and now is revised as the type species of Sinoagetopanorpidae fam. nov. Three genera (two new genera) and ten new species of this new family are described and illustrated: Sinoagetopanorpa permiana Lin, Nel and Huang, 2010, S. nigra sp. nov., S. rotunda sp. nov., S. lini sp. nov., S. minuta sp. nov., S. elegans sp. nov., S. grimaldii sp. nov., S. magna sp. nov., Raragetopanorpa zhangi gen. et sp. nov., Permoagetopanorpa yinpingensis gen. et sp. nov. and P. incompleta sp. nov. Some isolated hind wings are described and illustrated, although it is difficult to assign them to any particular species. As a dominant mecopteran lineage in the Yinping Formation, Sinoagetopanorpidae represents an endemic group that might have independently evolved on the Yangtze Platform.

A new species of Polydesmidae (Myriapoda, Diplopoda, Polydesmida) from the mid-Cretaceous Burmese amber.

A new species of the flat-backed millipede family Polydesmidae, Propolydesmus cretaceus sp. nov., is described from the mid-Cretaceous Burmese amber. Detailed morphological characters are provided on the basis of 3 well-preserved adults (2 males and 1 females), 2 female subadults, and 14 additional specimens, using confocal laser scanning microscopy (CLSM) and X-ray micro-computed tomography (CT) with computer-aided 3D-reconstructions. The new species can be placed in the extant genus Propolydesmus. It majorly differs from other congeners due to the stronger gonopod acropodite and the presence of a bipartite gonopod exomerite.

A new species of Burmalestes Tomaszewska & lipiski from mid-Cretaceous Kachin amber (Coleoptera: Endomychidae).

The second species of the extinct genus Burmalestes Tomaszewska & lipiski, B. jingruoyaae Li & Cai sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. The new species shares characters with both Burmalestes (antennomere 5 elongate and procoxae subcontiguous) and Cretaparamecus Tomaszewska et al. (protibiae toothed and pronotum without basolateral sulci), providing valuable information on the morphological variability of this group.

Palaeoparasycorax globosus Stebner et al., 2015 from the mid-Cretaceous amber of Myanmar: Description of a mating pair.

A mating pair of Palaeoparasycorax globosus Stebner et al., 2015 from the mid-Cretaceous Burmese amber is illustrated and described. The male is redescribed, and the female genitalia of this species is described for the first time. This discovery allows for a better understanding of this fossil sycoracines characteristics and further demonstrates the bioinclusion richness of the mid-Cretaceous Burmese amber. A list of all Cretaceous Psychodidae is given.

First record of fossil psocodeans in copula from mid-Cretaceous Burmese amber.

We report the first discovery of barklice preserved in copula from amber dating back to the mid-Cretaceous, thus documenting the oldest preserved reproductive behaviour of Psocodea. The new finding provides new insight into the evolution of copulatory behaviour in Trogiomorpha. Moreover, we describe and illustrate the new fossil material of Burmempheria densuschaetae (= Latempheria kachinensis) in the extinct family Empheriidae and Longiantennum fashengi in the extinct family Archaeatropidae, two diverse and widely distributed groups during the Cretaceous. No significant sexual dimorphism is recorded, apart from variation in size where males are larger. The taxonomy of Cretaceous empheriids from Burmese amber is revised and discussed.

A new genus of japygids (Diplura: Japygidae) in mid-Cretaceous amber from northern Myanmar.

Diplura is a cryptic and edaphic group of hexapod animals characterized by the presence of filiform or pincer-like cerci located at the end of the abdomen. As one of the early diverging lineages of Hexapoda, diplurans play a crucial role in unraveling the origin of the hyperdiverse insects. The fossil record of diplurans, however, is exceptionally limited due to their delicate bodies and habitat requirements. Here we report the discovery of a new japygid, Cretojapyx huangi gen. et sp. nov., entombed in mid-Cretaceous Kachin amber (northern Myanmar). This specimen exhibits distinctive features, including the well-developed carinae on abdominal segment X and cerci, left cercus lacking a prominent tooth and denticles, and right cercus with a postmedian tooth followed by uniseriate round denticles. Our finding provides a unique opportunity to gain valuable insights into the evolutionary history of this ancient lineage and deepen our understanding of terrestrial ecosystems during the Mesozoic.

New material of Cretaceoushormiops Loureno from mid-Cretaceous Burmese amber (Arachnida: Scorpiones: Protoischnuridae).

Among the scarce Mesozoic fossils, protoischnurid scorpions (Arachnida: Scorpiones: Protoischnuridae) represent a Cretaceous extinct group. In this study, we present the description of a new protoischnurid fossil, assigned to the genus Cretaceoushormiops Loureno, from mid-Cretaceous Burmese amber. Distinguished by a median suture and a comparatively short anterior margin in its carapace, the new specimen differs from all other species within Cretaceoushormiops. Our discovery sheds further light on the high diversity of mid-Cretaceous scorpions.

A new clam shrimp (Branchiopoda: Diplostraca: Spinicaudata) from the Upper Jurassic in the Jiyuan Basin, China and its biostratigraphic significance.

A new spinicaudatan species Triglypta jiyuanensis Liao & Huang sp. nov. is described from the Upper Jurassic Maao Formation in the Jiyuan Basin, northwestern Henan Province, China. The carapace of the new species is ornamented with punctae, linear arrangements of punctae, and radial lirae. The new species differs from those of the early Triglypta forms from the Middle Jurassic but closely resembles T. jianchangensis Wang, 2014 from the Upper Jurassic Tiaojishan Formation of western Liaoning Province. Our study provides new biostratigraphic evidence supporting that the Maao and Tiaojishan formations can be correlated. Moreover, we suggest that the Yangshuzhuang Formation in the Jiyuan Basin could correlate to the Haifanggou and the Longmen formations in the Yanliao area.

The first species of Thaumatomeropidae (Insecta: Mecoptera) from the Middle Triassic of China.

Thaumatomeropidae is an enigmatic mecopteran family previously known exclusively from the Triassic Madygen entomofauna of Kyrgyzstan. Thaumatomeropids display mosaic venation, closely resembling those of Meropeidae and Eomeropidae, yet distinguished by some more primitive characters. Here we describe and illustrate a new thaumatomeropid species, Thaumatomerope sinensis Lian & Huang, sp. nov., from the late Middle Triassic Tongchuan entomofauna of the Chang 7 Member of the Yanchang Formation near the Hejiafang Village, Tongchuan City, NW China. This new species is characterized by reduced Rs branches, and some unique forking patterns, including the single posterior last branch of Rs and multi-branched anterior first branch of M. It represents the first thaumatomeropid species reported outside Kyrgyzstan, indicating a broader geographical distribution of the family. Moreover, this discovery enhances the resemblance of mecopteran components between the Tongchuan and the Madygen entomofaunas.

A new species of Cicadocoris (Hemiptera, Coleorrhyncha, Progonocimicidae) from the Middle Jurassic of the Jiyuan Basin, China.

Progonocimicids are one of key representatives from the Middle-Late Jurassic Daohugou biota, the early assemblage of the Yanliao biota. Here we describe a new progonocimicid species, Cicadocoris henanensis sp. nov., from the Middle Jurassic Jiyuan Basin in central China. This not only represents a novel case indicating the abundance of progonocimicids during the Jurassic but also provides additional evidence substantiating the stratigraphic correlation between the Yangshuzhuang Formation in the Jiyuan Basin and the Haifanggou Formation in the Yanliao Region.

New stem-anisopteran dragonflies in the Jurassic of China (Odonata: Epiproctophora).

The odonatan asiopterid Turanopteron sinensis sp. nov. and the juragomphid Oxfordgomphus trescellulae gen. et sp. nov. are described on the basis of two new fossil wings from the Middle-Upper Jurassic of Henan Province in China. These taxa belong to ancient, Toarcian epiproctophoran stem groups of Anisoptera Selys, 1854. They show important affinities with taxa from the Karatau entomofauna in Kazakhstan. These groups progressively decrease and were replaced by more modern clades of Anisoptera during the Late Jurassic.

Discovery of Thripida from the Middle Jurassic Yanan Formation.

Thysanoptera, commonly known as thrips, constitutes a relatively diminutive insect order within the superorder Thripida Fallen, 1814, with at least 6000 described extant species. Thripida has been divided into three clades: Panthysanoptera Nel et al., 2012, Lophioneurida Tillyard, 1921, and Westphalothripidesidae Nel et al., 2012, primarily based on wing venation patterns (Nel et al., 2012).