A New Subgenus and Species of Priochirus from Mid-Cretaceous Kachin Amber (Coleoptera: Staphylinidae: Osoriinae).

As one of the largest families of beetles (Coleoptera), the Staphylinidae (rove beetles and their relatives) are rich not only in extant species but also in a comparatively robust fossil record. Despite this preponderance of available fossil material, fossils of the diverse subfamily Osoriinae remain rare. Here, we describe a new ososriine species, Priochirus trisclerite sp. nov., from the mid-Cretaceous amber of Myanmar. The new specimen is similar to the only other definitive fossil of the genus, Priochirus thayerae Yamamoto 2019, and both are placed in the extinct subgenus Eopriochirus subgen. nov. The new species differs noticeably in a number of morphological details in relation to the submentum, gular sutures and protibial crenulae. The new fossil provides further evidence for understanding the radiation of staphylinoid beetles.

New Fossil Xyelidae (Hymenoptera: Symphyta) from the Mesozoic of Northeastern China.

One new genus and species, Leptoxyela eximia gen. et sp. nov., and one new species, Scleroxyela cephalota sp. nov., are described and illustrated based on two well-preserved compression fossils from the Lower Cretaceous Yixian Formation and the Middle Jurassic Jiulongshan Formation of China, respectively. Leptoxyela eximia gen. et sp. nov. is placed in the tribe Angaridyelini, 1966 and Scleroxyela cephalota sp. nov. in the tribe Xyeleciini Benson, 1945; while both tribes are in the subfamily Macroxyelinae Ashmead, 1898 of Xyelidae. A key to the genera of Angaridyelini is provided. In addition, we investigated various angles between Rs+M and 1-Rs for known fossil species of Macroxyelinae, and we found the angle and the length of 1-Rs are correlated; however, we could not see any correlation between the angles and the fossil ages even within a tribe. Furthermore, based on Sc2 connected to R before Rs, the angle between Rs+M and 1-Rs, and the length of the first flagellomere, we believe that the tribe Ceroxyelini may have only one genus of Ceroxyela, and suggest that Isoxyela and Sinoxyela should be transferred to Gigantoxyelini.

The Oldest Evolutionary Lineage of Trichoneura Loew, 1850 (Diptera, Limoniidae) and the First Evidence of This Genus in Cretaceous Spanish Amber.

A new subgenus Cretalinea subgen. nov. of Trichoneura (Diptera, Limoniidae) is established with one new species: Trichoneura (Cretalinea) xavieri subgen. et sp. nov. This is the first report of the genus Trichoneura in Spanish amber and the first record of the genus from the Lower Cretaceous period. The oldest described species of Trichoneura is compared with other species of the genus with particular reference to those known species from the Upper Cretaceous. A list and key of fossil species of Trichoneura are given.

A Peculiar New Genus of Bibionomorpha (Diptera) with Brachycera-Like Modification of Antennae from Mid-Cretaceous Amber of Myanmar.

A new fossil genus of Bibionidae (Diptera: Bibionomorpha), Burmahesperinus gen. nov., from the mid-Cretaceous Burmese amber, is described and illustrated (type species Burmahesperinus antennatus sp. nov., the other two species included are B. conicus sp. nov. and B. pedicellatus sp. nov.). The new genus is tentatively placed in a new subfamily, Burmahesperininae subfam. nov. of the family Bibionidae. Its possible phylogenetic position is briefly discussed. The new genus, as well as the subfamily, possesses the wing venation similar to the recent genus Hesperinus Walker, 1848, in combination with Brachycera-like modification of both the male and female antenna and the overall habitus typical of fungus gnats (Sciaroidea).

Fossils Shed a New Light on the Diversity and Disparity of the Family Limoniidae (Diptera, Nematocera).

A new subfamily Drinosinae (Diptera, Limoniidae) is established with two fossil genera, Drinosa and Decessia gen. nov. with one new species, Decessia podenasi gen. et sp. nov. from Cretaceous Burmese amber. Additional description of Drinosa prisca is based on new material. A new subfamily shows unique reduction of radial veins combined with complete set of medial veins.

Diversity of the Fossil Genus Palaeoglaesum Wagner (Diptera, Psychodidae) in the Upper Cretaceous Amber of Myanmar.

Cretaceous Myanmar amber is abundant in inclusions belonging to the genus Palaeoglaesum. In addition, a significant morphological diversity among representatives of Palaeoglaesum can be observed. However, none of its representatives have been found in other fossil materials. Herein three new species: P. stebneri sp. nov., Skibinska and Krzeminski P. teres sp. nov. Skibinska and Albrycht, and P. pilosus sp. nov. Skibinska, Krzeminski and Zhang from Cretaceous Myanmar amber are described and illustrated. The very small size and characters of male hypopygium with aedeagus strongly bent and apically forked are pertinent to diagnosing the genus and species. New materials show that this genus and the whole subfamily Bruchomyiinae were probably more abundant and more diverse than the presently known extant fauna.

Extant Genus in the Mesozoic: Paleoplatyura Meunier (Diptera: Keroplatidae) Found in the Cretaceous Amber of Myanmar.

Three new species of Paleoplatyura Meunier, 1899, i.e., Paleoplatyura agnieszkae sp. nov., P. miae sp. nov., and P. magnifica sp. nov., are described and figured. The concept of the genus is briefly discussed, and its systematic position is clarified. A key to fossil species is provided. The genus Paleoplatyura is described from the Eocene Baltic amber. It is concluded that, in Baltic amber, this group is represented only by the type species, and the identity of the other two species is problematic. No additional specimens have been found so far in this amber. Therefore, the presence of as many as three new species in Burmese amber, certainly belonging to Paleoplatyura, is a confirmation of its occurrence already in the Mesozoic.

Behaviors and Interactions of Insects in Mid-Mesozoic Ecosystems of Northeastern China.

During the past 20 years, more than 1,600 species of well-preserved fossil insects, including members of over 270 families within 24 orders, have been described from the Middle Jurassic Yanliao Entomofauna and Early Cretaceous Jehol Entomofauna in Northeastern China. Diversified fossil insects not only document the origin, systematics, and early evolution of many lineages, but also reveal these lineages' behaviors and interactions with coexisting plants, vertebrates, and other insects in their ecosystems. Fossil evidence has been documented, for example, regarding insects' feeding and pollination mutualism with gymnosperms; ectoparasitic feeding on blood of vertebrates; camouflage, mimicry of gymnosperm plants, and eyespot warning; sound stridulation for attracting potential mates; and sexual display, mating, egg-laying, and parental care. In this article, we review the diverse taxonomy of mid-Mesozoic insects of Northeastern China and elucidate their behaviors and interactions within their ecosystems, which have impacted their early evolution and development into extant insects.

Intriguing and Beautiful: Adamacrocera adami gen. et sp. nov. from the Upper Cretaceous Amber of Myanmar Represents a New Subfamily of Keroplatidae (Diptera: Bibionomorpha).

A new fossil genus and species of Keroplatidae (Diptera, Bibionomorpha, Sciaroidea), Adamacrocera adami gen. et sp. nov., from the Upper Cretaceous Burmese amber is described and illustrated. Based on morphological evidence, it is placed in a new subfamily Adamacrocerinae subfam. nov. The new genus, as well as the subfamily, possesses the wing venation characteristic of the genera of some Sciaroidea incertae sedis, as well as that of the fossil families Archizelmiridae, Antefungivoridae and Mesosciophilidae, in combination with macrocerine-like habitus and male terminalia.

Review of Mesozoic Perissommatidae (Insecta: Diptera).

Perissommatidae is a peculiar relict nematoceran family with one extant genus inhabiting Australia and South America. The family is known since the Middle Jurassic, but the fossil record is very poor and is restricted to Asia. The description of three species of Collessomma gen. nov. from Lower Cretaceous of Transbaikalia and Mongolia-C. sibirica sp. nov., C. gnoma sp. nov., and C. mongolica sp. nov.-expands our understanding of the family in the Mesozoic, when Perissommatidae were much more diverse morphologically and spread geographically then now. Two previously described genera Gurvaniella Kovalev, 1986 and Limnorhyphus Hong, 1983 are transferred to the Perissommatidae.

Revision of fossil Metretopodidae (Insecta, Ephemeroptera) in Baltic amber - Part 4: Description of two new species of Siphloplecton Clemens, 1915, with notes on the new S. jaegeri species group and with key to fossil male adults of Siphloplecton.

The Siphloplecton jaegeri species group is established here for three extinct species, namely for the earlier described Siphloplecton jaegeri Demoulin, 1968, and for two new species from Eocene Baltic amber, Siphloplecton landolti sp. nov. and Siphloplecton studemannae sp. nov. Based on the well-preserved specimens of these species, a diagnosis is provided for the newly established species group. Representatives of the S. jaegeri species group are characterized by the presence of large, medially contiguous eyes, stout pointed setae along the outer margin of the foretibia, three intercalaries in the cubital field of the forewing, and elongated penis lobes, which are apically triangular or rounded, medially contiguous, and with a V-shaped cleft apically. Further new specimens of the S. jaegeri species group are documented that cannot be attributed to species level due to their poor preservation. Finally, a key to male adults of fossil species of Siphloplecton is given.

The last batrachideine of Europe: A new genus and species of pygmy grasshopper (Orthoptera: Tetrigidae) from Eocene Baltic amber.

A new genus and species of pygmy grasshopper (Orthoptera: Tetrigidae) is described from Eocene Baltic amber. Danatettix hoffeinsorum gen. et sp. nov. is assigned to the subfamily Batrachideinae based on antennae with more than 19 antennomeres, sulcate mesofemora, and rectangular paranota. This species is readily distinguished from other batrachideines by a markedly produced vertex, pronotum with divergent internal and external lateral carinae, and highly setiferous female lateral basivalvular sclerite with scabrose integument. The morphology of Danatettix suggests placement within the here defined Tettigidea genus group (comprising Eutettigidea Hancock, 1914, Paurotarsus Hancock, 1900, and Tettigidea Scudder, 1862) and suggests that the latter had diverged from the new Scaria genus group (comprising Eotetrix Gorochov, 2012, Rehnidium Grant, 1956 and Scaria Bolívar, 1887) by the Early Eocene.

New anaxyelids (Hymenoptera: Anaxyelidae) from the Cretaceous of Asia.

Four new genera and five new species of anaxyelids are described from the Cretaceous of Asia: Mangus magnus gen. et sp. nov. from the Aptian of Mongolia (Bon-Tsagan), Urosyntexis undosa sp. nov., Parasyntexis khasurtensis gen. et sp. nov., both from the Early Cretaceous of Transbaikalia (Khasurty), Dolichosyntexis transbaikalicus gen. et sp. nov. from the Hauterivian-Barremian of Transbaikalia (Baissa), and Curiosyntexis magadanicus gen. et sp. nov. from the mid-Upper Cretaceous of NE Siberia (Obeshchayushchiy). Early Cretaceous is the time of the highest diversity of Anaxyelidae. In this epoch these sawflies are represented with all four subfamilies comprising the group. In Late Cretaceous anaxyelid diversity and abundance rapidly decrease and they are represented with the only subfamily Syntexinae. The anaxyelid collection of Palaeontological Institute (Moscow), the most representative collection of fossil anaxyelids in the world, has been completely revised, identified and described. The list of identifications is provided.

Review of Mycetobia Meigen, 1818 (Diptera, Anisopodidae) in the Eocene ambers.

A revision of the genus Mycetobia Meigen, 1818 from the Eocene is presented. Redescription of Mycetobia connexa Meunier, 1899 known from the Baltic amber is given and documented by photographs and drawings. Five new species of Mycetobia from Eocene resins are described, four from Baltic amber: Mycetobia christelae sp. nov., Mycetobia hansi sp. nov., Mycetobia silvia sp. nov., Mycetobia szwedoi sp. nov. and one from the Ukrainian amber: Mycetobia perkovskyi sp. nov. Key to the species of Mycetobia known from the Eocene is provided.

Forgotten giants: new Anaxyelidae (Hymenoptera) from the Jurassic of Karatau.

Three new species of Anaxyelidae from the Middle-Upper Jurassic of Karatau (Kazakhstan) are described: Brachysyntexis tenebrosa sp. nov., B. tigris sp. nov., and Kulbastavia grandis sp. nov. By the size of the body, B. tenebrosa and K. grandis are the largest Jurassic species of the family. In the Jurassic period, the Anaxyelidae were represented only by the subfamily Anaxyelinae. They were found in three localities: Daohugou (China, 17 specimens), Karatau (Kazakhstan, 27 specimens) and Khoutiyn-Khotgor (Mongolia, 1 specimen). A list of all known Jurassic findings of Anaxyelidae from the collections of the Palaeontological Institute (Moscow) is given.

Experimental degradation of helicoidal photonic nanostructures in scarab beetles (Coleoptera: Scarabaeidae): implications for the identification of circularly polarizing cuticle in the fossil record.

Scarab beetles (Coleoptera: Scarabaeidae) can exhibit striking colours produced by pigments and/or nanostructures. The latter include helicoidal (Bouligand) structures that can generate circularly polarized light. These have a cryptic evolutionary history in part because fossil examples are unknown. This suggests either a real biological signal, i.e. that Bouligand structures did not evolve until recently, or a taphonomic signal, i.e. that conditions during the fossilization process were not conducive to their preservation. We address this issue by experimentally degrading circularly polarizing cuticle of modern scarab beetles to test the relative roles of decay, maturation and taxonomy in controlling preservation. The results reveal that Bouligand structures have the potential to survive fossilization, but preservation is controlled by taxonomy and the diagenetic history of specimens. Further, cuticle of specific genus (Chrysina) is particularly decay-prone in alkaline conditions; this may relate to the presence of certain compounds, e.g. uric acid, in the cuticle of these taxa.

New ichneumonids (Hymenoptera, Ichneumonidae) from the Eocene Tadushi Formation, Russian Far East.

Ichneumonidae constitute one of the largest families of organisms, but their fossil record is severely understudied, which precludes inferences about their early evolutionary history. We here describe a new genus and two new species of ichneumonids from the Early Eocene Tadushi Formation (Russian Far East). The new taxa are Crusopimpla tadushensis gen. et sp. nov. and Dolichomitus? saxeus sp. nov. Pimpla rediviva (Brues) is redescribed and placed in the genus Crusopimpla. This new genus is unique within Pimplinae in having a completely developed propodeal carination and probably represents one of its most basal lineages. Using a phylogenetic hypothesis of the subfamily, we discuss potential pathways of morphological evolution in the group, which will provide a basis for future placement of pimpline fossil taxa.

From Fossil Parasitoids to Vectors: Insects as Parasites and Hosts.

Within Metazoa, it has been proposed that as many as two-thirds of all species are parasitic. This propensity towards parasitism is also reflected within insects, where several lineages independently evolved a parasitic lifestyle. Parasitic behaviour ranges from parasitic habits in the strict sense, but also includes parasitoid, phoretic or kleptoparasitic behaviour. Numerous insects are also the host for other parasitic insects or metazoans. Insects can also serve as vectors for numerous metazoan, protistan, bacterial and viral diseases. The fossil record can report this behaviour with direct (parasite associated with its host) or indirect evidence (insect with parasitic larva, isolated parasitic insect, pathological changes of host). The high abundance of parasitism in the fossil record of insects can reveal important aspects of parasitic lifestyles in various evolutionary lineages. For a comprehensive view on fossil parasitic insects, we discuss here different aspects, including phylogenetic systematics, functional morphology and a direct comparison of fossil and extant species.

A new family of aphids (Hemiptera, Sternorrhyncha) from the Lower Cretaceous of Baissa, Transbaikalia.

The family Rasnitsynaphididaefam. n. has a unique combination of characters: 9-segmented antennae; rhinaria arranged in many transverse rows, surrounding the antennal segments; segment IX narrower than other segments of flagellum, always without rhinaria; cubitus branches separated; ovipositor present; siphuncular pores absent. The new family comprises the genus Rasnitsynaphisgen. n. with three species, Rasnitsynaphis ennearticulatasp. n., Rasnitsynaphis coniunctasp. n., and Rasnitsynaphis quadratasp. n., all from the Lower Cretaceous of Transbaikalia.

Palerasnitsynus gen. n. (Trichoptera, Psychomyiidae) from Burmese amber.

Palerasnitsynus ohlhoffigen. et sp. n. is described fromBurmese amber of late Albian (Lower Cretaceous) age. This is the first record of the family Psychomyiidae from Burmese amber, and the earliest fossil record of the family. The genus Palerasnitsynusgen. n. differs from all other known psychomyiid genera by the absence of fork III in the forewings.