Larvae of lacewings (Neuroptera) are (mostly) ferocious predators, and the most well known are the larvae of antlions. In the larger group of antlion-like lacewings, the larvae resemble those of antlions to a certain degree but have certain peculiarities. Larvae of the group Nemopteridae can be easily separated into two groups: the larvae of Crocinae (thread-winged lacewings), also known as long-necked antlions, have relatively slender mouthparts and long necks, as the name suggests; the larvae of Nemopterinae (spoon-winged lacewings) have stout mouthparts and bodies. We here report new lacewing larvae of the group Nemopteridae from about 100-million-year-old Kachin amber, Myanmar. The new findings significantly expand the dataset of these animals in the fossil record. Quantitative analyses comparing the fossil and extant larvae support earlier indications that the morphological diversity of the fossils was in fact larger, yet the results are not as conclusive as in other ingroups of Neuroptera. The comparison also indicates that convergent evolution played an important role in the evolution of larvae of antlion-like lacewings.

A new fossil genus and species of the mayfly family Ameletopsidae, Paprika atsukochibae gen. & sp. nov., is described from mid-Cretaceous Kachin amber of northern Myanmar. The specimen represents a female imago and constitutes the oldest known imaginal fossil of the family. Paprika gen. nov. exhibits a unique combination of the characters in wing venation that distinguish it from both extant and extinct Ameletopsidae. Although the new genus is assigned to Ameletopsidae based on imaginal morphological characters, it cannot be placed within the existing subfamilies due to the absence of male or caudal appendage characters. This discovery represents the oldest imaginal Ameletopsidae fossil discovered so far and provides the first fossil record of the family in Asia. The finding supports a broader, possibly Pangean, distribution and origin of Ameletopsidae during the Mesozoic and contributes to the understanding of the evolutionary history and paleobiogeography of Siphlonuroidea. Moreover, the presence of such a lineage in mid-Cretaceous Myanmar suggests greater ecological and geographical diversity within this mayfly assemblages than previously recognized.

A new genus and species of Bernaeinae whiteflies from the early Cenomanian Kachin (Myanmar) amber is described. Patsenga danielburckhardti Drohojowska et Szwedo gen. et sp. nov. is the third representative of Bernaeinae from Kachin amber, exhibiting a combination of plesiomorphic characteristics, including the retention of a median ocellus, and the presence of vein M, alongside apomorphic states that are also shared with other contemporaneous Bernaeinae from this fossil resin. Morphological characters of the newly described fossil are briefly discussed.

Abstract The evolutionary arms race between insects and their predators has fueled remarkable defensive adaptations, offering insights into ecological dynamics across deep time. Fossils provide critical evidence for studying the evolution of defense strategies. Here, we describe a new lineage of Clambidae from mid‐Cretaceous Kachin amber, Scutacalyptus kolibaci gen. et sp. nov. Scutacalyptus stands out within the family due to the flattened body and fully explanate body margins. The diversity of defensive morphotypes in Cretaceous Clambidae, including conglobators like Sphaerothorax , semi‐flattened forms like Acalyptomerus , and shield‐formers like Scutacalyptus , highlights their developmental plasticity and suggests ecological differentiation in response to varied predation pressures during the late Mesozoic. This morphological divergence reflects niche partitioning in the Cretaceous forest floor ecosystem, driven by a diverse predator array including spiders, ants, lizards, and birds. The coexistence of clambids with spines or explanate margins parallels adaptations in the modern, unrelated Cassidinae, where tortoise beetles use explanate margins and some leaf‐mining beetles use spines, each tailored to counter specific predation pressures. These parallel strategies reveal how different defenses likely addressed distinct ecological challenges in the mid‐Cretaceous.

Cretoscraptella crucifera gen. et sp. nov. is described as the first named representative of the tribe Allopodini (Scraptiidae) from the Mesozoic amber deposits, based on a single adult beetle inclusion in mid-Cretaceous Kachin amber, northern Myanmar (ca. 99 Ma). The systematic placement of Quasianisoxya curonensis Alekseev, 2015 (originally attributed to Melandryidae) and Samlandotoma seidlitzi Alekseev, 2019 (family incertae sedis within Tenebrionoidea) from Baltic amber are revisited. These previously misplaced Cenozoic species are transferred to the tribe Scraptiini within Scraptiidae. A checklist of known fossil scraptiids beetles (18 described species in 9 genera) is compiled and provided.

Sand flies (Diptera, Psychodidae, Phlebotominae) are medically important insects with an interesting, but poorly understood, evolutionary history. The abundance and diversity of inclusions of these flies in Myanmar (Burmese) amber provide valuable data on their geological history. In this study, a new genus and species of sand fly, Longiphlebes excelsior gen. et sp. nov., is described based on an inclusion from Cretaceous Kachin amber (northern Myanmar). The systematic position of the new genus is discussed, and its morphological characters are compared with those of selected extant and fossil Phlebotominae taxa. The morphology of the genitalia, head, and wing suggests a closer relationship to recent Old World Phlebotominae fauna than to the more derived fossil genera such as Phlebotomites or the phlebotomid-like Eophlebotomus. This discovery broadens our understanding of Cretaceous sand flies, especially their evolution and diversity.

The thrips diversity preserved in Kachin amber is remarkably high, with numerous new species awaiting discovery. In this paper, two new species of Thripidae: Euthythrips longialatus gen. et sp. nov. and Minythrips exquisitus gen. et sp. nov., plus five new species of Melanthripidae: Aspistothrips fortis gen. et sp. nov., Aspistothrips decorus sp. nov., Areiothrips bellator gen. et sp. nov., Charismathrips longiantennatus gen. et sp. nov., Charismathrips exaridus sp. nov., are systematically described, expanding the fossil record of Thysanoptera from Kachin amber. Through comparative morphological analyses of fossil taxa, we propose that two characters likely represent plesiomorphic traits of Thysanoptera: nine antennomeres and duplicated cilia arranged parallel to regular fringe cilia. By synthesizing existing research on thrips environmental interactions, this study briefly analyzes the adaptive evolution of thrips during floral ecosystem turnover.

The family Perlidae is a diverse group of stoneflies frequently found in Mid-Cretaceous Kachin amber from northern Myanmar. However, no detailed descriptions of genuine perlid larvae from amber specimens have been reported. In this study, the first well-preserved genuine stonefly larva from Kachin amber is described and classified within the Perlidae. Morphological analysis reveals its closest affinity to larvae of the extant genus Caroperla Kohno, 1946 (subfamily Acroneuriinae, tribe Kiotinini), yet highlights unique traits suggesting affiliation with an undescribed lineage. Phylogenetic and morphospace analyses based on larval morphology consistently recover this fossil in an intermediate phylogenetic position, raising questions about the monophyly of subfamilies and tribes within Perlidae. Notably, the specimen exhibits functional adaptations such as predatory mouthparts and chloride cell-bearing gills identical to modern Perlidae, indicating morphological stasis since the mid-Cretaceous. This discovery not only underscores the critical role of amber in preserving aquatic immature stages but also provides novel insights into the evolutionary trajectories and ecological resilience of perlid larvae in ancient freshwater ecosystems.

A new tribe, Burmoptarthrini Legalov, trib. nov. from the subfamily Brenthorrhininae (Nemonychidae), with a new genus and species, Burmoptarthrus storozhenkoi Legalov, gen. et sp. nov., is described and illustrated from late Cretaceous Kachin amber. This new tribe can be distinguished from the tribes Eccoptarthrini, Brenthorrhini and Distenorrhinini by its strongly constricted head capsule behind the eyes, which protrude strongly from the head. It also has a coarsely punctate and granulated pronotum and head, as well as granulated lateral pronotal margins. A key to the tribes and a list of described species of the subfamily Brenthorrhininae are compiled.

A key aspect of the holometabolan evolutionary success is their metamorphosis. It allows larvae and adults to exploit quite different resources and reduce competition between the two. The often strongly differing morphology of larvae and adults is mediated by the specific intermediate stage, the pupa. Fossil pupae provide valuable information for the reconstruction of the evolutionary history of this so important developmental stage. However, pupae are relatively rarely found in the fossil record, and they seem even less often depicted in the literature. Here, we report two new fossil pupae preserved in about 100 million years old Kachin amber, Myanmar. These represent the first fossil pupae of the group of snakeflies, Raphidioptera. The two specimens resemble modern snakefly pupae in overall morphology and especially in the morphology of the ovipositor. However, they also differ in certain aspects, indicating differences in developmental timing. One specimen is particularly notable for its long, curled antennae. Extant snakeflies have rather short antennae in all life stages. Yet, in the Cretaceous few species have long antennae as adults, and also some larvae are known with rather long antennae. The other pupa has shorter antennae and is preserved in the same amber specimen as another snakefly, a larva with rather long antennae. The new snakefly pupa with its extraordinarily long antennae underpins the exceptional evolutionary radiations in the Cretaceous.

Abstract Pseudoscorpiones are a group of small‐sized to medium‐sized arachnids under the species‐rich Chelicerata. They are found in many terrestrial habitats, normally cryptic, including leaf litter and soil, under tree bark or rocks. The fossil record of pseudoscorpions is mainly composed of species belonging to extinct genera in extant families, with a small number of taxa described from the famous Kachin amber, sometimes referred to as Burmese amber or Burmite (12 species in six families). Here, we describe a well preserved male specimen of pseudoscorpion from mid‐Cretaceous Kachin amber, representing the first fossil record of Cheliferidae from Burmese amber. This new taxon, Echinochelifer curvatus gen. & sp. nov., is characterized by elongate tubercle‐bearing pedipalps and several trichobothrial features. Based on these, we discuss the systematic placement and palaeoecological implications of the new taxon in Burmese amber.

First reliable fossil record of the family Isonychiidae (Insecta, Ephemeroptera) from Cretaceous Kachin amber

Abstract Insects are the most species-rich group of animals, and the high morphological complexity and spectacular diversification of mouthparts among insects are crucial to their prosperity. Currently, the knowledge on insect mouthpart types remains largely stationary, yet little evidence has been documented to illustrate the transitional forms. In this study, we report for the first time a series of fossil specimens which reveal the successive process between two types of insect mouthparts. Correspondingly, three new families including six new species are established based on such mid-Cretaceous Kachin amber to place these new fossil records. Starting from the morphological differences in the mouthparts of the newly defined families and the extant water boatmen families, we further deduce the structural homology between different mouthpart types and find the coevolution between the mouthparts and the forelegs in the phylogenetic context of total evidence. Our discovery provides direct evidence of the transformation process of the water boatmen’s mouthparts from a sucking to a triangular type. This study provides new evidence and perspectives for in-depth understanding of the evolutionary process of insect mouthparts.

Two new members of Tridactylidae Brull, 1835 are described based on specimens found in mid-Cretaceous Kachin amber from Northern Myanmar. Duappendactylus melanocephalus gen. et sp. nov. is assigned to the family based on its two-segmented cerci and inflated mesotibia. It is similar to Birmitoxya Gorochov, 2010 by its lack of (visible) paraproctal processes and the presence of an elongated, upward-facing subgenital plate, but differs from that genus in several other aspects of its morphology. Additionally, we describe Hiemalidactylus eileenae gen. et sp. nov. based on a well preserved, presumably nymphal specimen. It is assigned to Tridactylidae based on the two-segmented cerci and the inflated mesotibia. Like the two aforementioned genera, Hiemalidactylus does not have cerciform paraproctal processes. However, this genus differs from Birmitoxya and Duappendactylus by not having an elongated subgenital plate. Instead, the paraproct is elongated and reaches almost the length of the basal segment of the cercus. These new species of Tridactylidae raise the diversity of this family known from Kachin amber to nine genera and eleven species.

The highly diverse group of rove beetles, Staphylinidae, displays a great morphological variety across both adult and larval stages. However, due to the often cryptic habitats of their larvae, comprehensive descriptions of larval morphologies across extant ingroups remain incomplete. Also, the fossil record of rove beetle larvae appears to be sparse to date. We report here 35 newly identified fossil larvae of Staphylinidae from eight pieces of Myanmar Kachin amber, dating to the Cretaceous. Notably, one amber piece preserves three larval syninclusions, while another contains nine adults alongside twenty-six larvae, providing rare evidence of larval-adult co-occurrence in ancient environments. Given the predominantly predatory life cycle of extant rove beetles, the morphological similarities of these fossils to modern groups suggest comparable ecological roles in the Cretaceous, likely involving specialised forward-protruding mandibles adapted for a predatory lifestyle. A morphometric analysis of larvae of Staphylinidae alongside other extant and fossil predatory insect larvae still revealed significant differences between extant and fossil rove beetle larvae. Furthermore, Cretaceous rove beetle larvae differ from Cretaceous lacewing larvae in their head and mandible shape. In the modern fauna, the diversity of lacewing larvae is lower, and some modern rove beetle larvae now occupy areas formerly occupied by lacewing larvae. This result indicates that rove beetle larvae diversified after the Cretaceous, taking over certain ecological functions of lacewing larvae, likely representing a case of ecological substitution.

ABSTRACTWe describe and illustrate Fantosmium qizhihaoi gen. et sp. nov., a new histerid beetle from mid‐Cretaceous Kachin amber, and evaluate its phylogenetic position based on morphological characters. Our analysis recovers Fantosmium as part of the extant subfamily Onthophilinae, allied to the Cretaceous genera Cretonthophilus Caterino et al., Phasmister Caterino, and Carinumerus Caterino. It resembles these fossil genera in possessing ventrally open hypomeral antennal cavities and a projecting prosternal lobe. Fantosmium is particularly distinctive in its elytral morphology, exhibiting weakly elevated elytral carinae ornamented with small denticles, an intercarinal surface bearing irregular reticulate sculpture, explanate and irregularly punctate epipleura, and a strongly undulate posterior elytral margin. The discovery of Fantosmium provides new insights into the early evolutionary history and morphological diversity of Onthophilinae.

ABSTRACTWe describe and illustrate Zavoticus yini gen. et sp. nov., a fossil beetle of Euaesthetinae (Staphylinidae) from mid‐Cretaceous Kachin amber, and evaluate its phylogenetic placement based on morphological characters. Zavoticus shares several key features with the Octavius generic group, including a distinct metendosternal stalk, two pairs of parasclerites on abdominal segments IV–VI, and apically attached abdominal intersegmental membranes. It differs from the two extant genera of the Octavius generic group, Octavius and Protopristus, primarily by having only a very weak and indistinct dorsal nuchal depression. The discovery of Zavoticus adds to the limited but growing fossil record of Euaesthetinae and provides new insight into the early diversification of this group.

We report the discovery of remarkable fossil mites referred to a new genus Punkochyzeria gen. nov. (Trombidiformes: Chyzeriidae) found in mid-Cretaceous Kachin amber from Myanmar. The postlarval stages of these mites possess unusually long tufts of dorsal opisthosomal setae. The mites were initially identified as Parachyzeria Hirst, 1926, but detailed morphological analysis revealed several key characters, including the absence of a paradont or basidonts on the palptibia, suggesting a new genus. We describe three new species, Punkochyzeria minaevi sp. nov., Punkochyzeria makolae sp. nov. and Punkochyzeria khoyi sp. nov., which are distinguished by the form of the dorsal opisthosomal setae, the odontus/palptarsus ratio and the number of setae on the palptibial ctenidium. We also present an identification key to the species of the genus Punkochyzeria and describe four specimens of this genus, which are difficult to attribute to any particular species, because of their poor state of preservation. We discuss the erectile function of the long dorsal setae. Notably, the individuals of P. makolae and P. khoyi carry other mites as syninclusions among the long tufts of setae, although phoretic relationship may be accidental. This discovery extends the known diversity of the family Chyzeriidae to the Cretaceous and provides new insights into their evolutionary history and ecological interactions.

Abstract Beetle larvae are common occurrences in modern terrestrial and freshwater fauna. We can assume that this was the case in the past as well, yet fossil beetle larvae are still reported relatively rarely. Here we report fossil larval specimens of the group of click beetles, Elateridae, from Kachin amber. The specific ecological role of the larvae can be gleaned from the specimens, they are predators, most likely wood-associated. The larvae seem differentiated from other common types of predatory larvae, the most common being lacewing larvae, based on a quantitative morphological comparison of head and mandible shape. We emphasise the use of fossil beetle larvae for functional ecological comparisons, even if the exact taxonomic relationships are unclear, because they can still provide important information for palaeoecological questions.

A new genus of the family Spathiopterygidae (Hymenoptera: Diaprioidea) from mid-Cretaceous Kachin amber