mid-Cretaceous Amber Research Articles

Investigation of Cretodorus (Hemiptera: Fulgoromorpha: Mimarachnidae) based on new adult and nymph fossils from mid-Cretaceous Myanmar amber

Here we report a new species, Cretodorus lijuanae sp. nov., of extinct Mimarachnidae from mid-Cretaceous amber of northern Myanmar. C. lijuanae sp. nov. was described based on one adult and three nymphal fossils. The new adult specimen exhibits the diagnostic features of Cretodorus and possesses a unique number and arrangement of sensory pits in the pronotum: nine sensory pits on one side, with five sensory pits between median and pronotal carinae and four sensory pits between lateral carina and margin, which is consistent in the nymphs. We also conduct morphometric analyses of forewings of all known species of Cretodorus, demonstrating that morphometrics are effectively discriminative for identifying Cretodorus fossils featuring few longitudinal veins and minimal differences in venation. Additionally, we report the nymphal fossils of Mimarachnidae for the first time. Three nymphal fossils, preserved in the same piece of amber alongside the adult specimen, exhibit the same nodule pattern on the thoracic notum in dorsal view, suggesting a feature linking adult and nymph of Mimarachnidae. These new specimens show morphological characteristics of the different developmental stages of C. lijuanae sp. nov., increasing the diversity of the Mimarachnidae in mid-Cretaceous amber from Myanmar. The preservation of three nymphs of the same age with an adult in the same piece of amber likely indicates aggregation behaviour in Mimarachnidae.

The oldest fossil record of Philopotinae (Diptera: Acroceridae) from the mid-Cretaceous amber of Northern Myanmar

A new genus and species of Acroceridae Leach, 1815, Burmophilopota wintertoni gen. et sp. nov., is identified from mid-Cretaceous Burmese amber, representing the oldest member of Philopotinae Schiner 1868. Based on morphological comparisons, Burmophilopota wintertoni gen. et sp. nov. most likely represents a stem group of the Philopotinae. The new material with well-preserved details of mouthparts and complete wing venation suggests that the new species could possibly be a pollinator for the angiosperms. This finding enhances our understanding of early origin and evolution of pollinating flies during the Mesozoic period.

Three new species of the extant genus Eucinetus from mid-Cretaceous amber of northern Myanmar (Coleoptera: Eucinetidae)

Three new species of plate-thigh beetles are described and figured from mid-Cretaceous Kachin amber, all representing the extant genus Eucinetus Germar. The species, Eucinetus debilispinus Li & Cai sp. nov., E. panghongae Li & Cai sp. nov., and E. zhenhuai Li & Cai sp. nov., are distinguished from each other by the forms of the antennomeres, leg spination, and form of the spurs. The genus Eucinetus represents a key example of long-term evolutionary stasis with a subcortical lifestyle. This further demonstrates the role of stable cryptic microhabitats in the persistence of some lineages over vast spans of geological time.

The earliest haplodiplatyid earwig, represented by a new genus from mid-Cretaceous Kachin amber (Dermaptera: Haplodiplatyidae)

Summary Fossils of the early-diverging neodermapteran families Diplatyidae and Haplodiplatyidae are rare, and for the latter have confined to a single Miocene occurrence. Here we report a new genus and species of haplodiplatyid earwig in mid-Cretaceous amber from southern Asia. Zeugmadiplatys cheni n. gen., n. sp. shares many features with extant Haplodiplatys Hincks, 1955, especially the simple, dentiform metaparameres of the male genitalia, but differs notably in the development of the compound eyes, antennae, abdominal tergites and sternites, and ventrally flattened cercal forceps with weakly crenulate to serrate mesal margins. The discovery of the new fossil extends the fossil record of Haplodiplatyidae by approximately 80 million years and provides a crucial calibration point for divergence-time estimates in the diversification of Neodermaptera.

Foveapeltis gen. nov., an unusual cleroid genus with large hypomeral cavities from mid-Cretaceous amber (Coleoptera: Cleroidea).

Beetles have a remote evolutionary history dating back to the Carboniferous, with Mesozoic fossils playing a pivotal role in elucidating the early evolution of extant families. Despite their exceptional preservation in amber, deciphering the systematic positions of Mesozoic trogossitid-like beetles remains challenging. Here, we describe and illustrate a new trogossitid-like lineage from mid-Cretaceous Kachin amber, Foveapeltis rutai Li, Kolibáč, Liu & Cai, gen. et sp. nov. Foveapeltis stands out within the Cleroidea due to the presence of a significant large cavity on each hypomeron. While the exact phylogenetic placement of Foveapeltis remains uncertain, we offer a discussion on its potential affinity based on our constrained phylogenetic analyses.

Two new species of Burmusculidae (Hymenoptera: Pompiloidea) in mid-Cretaceous amber from northern Myanmar

Two new species of Burmusculidae (Hymenoptera: Pompiloidea) in mid-Cretaceous amber from northern Myanmar

A new genus and species of Nabinae (Heteroptera: Cimicomorpha: Nabidae) from mid-Cretaceous Burmese amber

A remarkable new genus and species, Mecocollaris simplipodus gen. et sp. nov. is described from mid-Cretaceous amber. It is the second fossil record of Nabinae from Myanmar amber. The new species is distinguished from other nabids based on labial segment Ⅲ longer than the combination of segments I, Ⅱ and Ⅳ, hind tibia without clear row of setae corresponding to stiff setae associated with the Ekblom’s organ. By comparing extant species and fossil records of Nabidae, the evolution of the Ekblom’s organ of nabids is discussed.

Geometric morphometric analyses of Micropterigidae lineages (Lepidoptera) with two new species from mid-Cretaceous amber of northern Myanmar

A new genus with two new species of Micropterigidae, Terncladus lunatus Han, Zhang et Ren gen. et sp. nov. and Terncladus halonatus Han, Zhang et Ren sp. nov., are erected based on three well-preserved specimens in Late Cretaceous Kachin amber. The new genus can be identified by hind wing with veins Sc unforked, no trace of free R, and Rs three-branched. Furthermore, we applied Geometric Morphometric Analyses (GMA) to study 26 species with well-preserved forewings of Micropterigidae and presented the results for the first time. The GMA results confirmed the classification of the new genus and shed light on the differences and diagnoses of the five monophyletic lineages of Micropterigidae. By comparing the geographical distribution and climatic environment characteristics of Micropterigidae in different geological periods, Micropterigidae have a relatively conservative adaptability to the environment during the evolutionary process.

Four new species of Burmomiles (Coleoptera, Cantharidae) from the mid-Cretaceous Burmese amber

Here we describe four new fossil species of soldier beetles, Burmomiles brevicollis sp. nov., B. angustipennis sp. nov., B. recticollis sp. nov., B. dentatus sp. nov., which are collected from the mid-Cretaceous amber in Kachin (Hukawng valley) of Northern Myanmar. They are placed in Burmomiles Fanti, Damgaard et Ellenberger, 2018 based on the male antennomeres IV‒X each with an antennal appendage inserted at a basal cavity on the ventral side, and tibiae hardly longer than femora, tarsomeres I normal and less than twice as long as II. Moreover, with more species added, the key for the identification of all Burmomiles species is updated. These results will significantly expand our knowledge on the species diversity of Burmite cantharids.

A winged relative of ice-crawlers in amber bridges the cryptic extant Xenonomia and a rich fossil record.

Until the advent of phylogenomics, the atypical morphology of extant representatives of the insect orders Grylloblattodea (ice-crawlers) and Mantophasmatodea (gladiators) had confounding effects on efforts to resolve their placement within Polyneoptera. This recent research has unequivocally shown that these species-poor groups are closely related and form the clade Xenonomia. Nonetheless, divergence dates of these groups remain poorly constrained, and their evolutionary history debated, as the few well-identified fossils, characterized by a suite of morphological features similar to that of extant forms, are comparatively young. Notably, the extant forms of both groups are wingless, whereas most of the pre-Cretaceous insect fossil record is composed of winged insects, which represents a major shortcoming of the taxonomy. Here, we present new specimens embedded in mid-Cretaceous amber from Myanmar and belonging to the recently described species Aristovia daniili. The abundant material and pristine preservation allowed a detailed documentation of the morphology of the species, including critical head features. Combined with a morphological data set encompassing all Polyneoptera, these new data unequivocally demonstrate that A.daniili is a winged stem Grylloblattodea. This discovery demonstrates that winglessness was acquired independently in Grylloblattodea and Mantophasmatodea. Concurrently, wing apomorphic traits shared by the new fossil and earlier fossils demonstrate that a large subset of the former "Protorthoptera" assemblage, representing a third of all known insect species in some Permian localities, are genuine representatives of Xenonomia. Data from the fossil record depict a distinctive evolutionary trajectory, with the group being both highly diverse and abundant during the Permian but experiencing a severe decline from the Triassic onwards.

A new lineage of pygidicranid earwigs from mid-Cretaceous amber of northern Myanmar (Dermaptera: Pygidicranidae)

Based on a well-preserved male specimen from mid-Cretaceous Kachin amber, we describe a new genus and its type species of earwig, Prodacnodes dupliforceps gen. et sp. nov. Prodacnodes has a unique combination of traits: large compound eyes, scape shorter than compound eye length, pronotum as broad as head, prosternum subtrapezoidal, wings present and fully developed, metatarsomere II not slanted apically, pygidium with short medioapical process, male external parameres with prominent subapical tooth mesally, and simple forceps. Our research contributes additional morphological features and information, enriching our comprehension of the lineages and diversity of Late Mesozoic earwigs.

Fern Diversity in the Mid-Cretaceous Amber Forests Revealed by Exceptionally Preserved Sporangium Types

Fern Diversity in the Mid-Cretaceous Amber Forests Revealed by Exceptionally Preserved Sporangium Types

A second species of Mesosmicrips Kirejtshuk, 2017 (Coleoptera: Smicripidae) from Kachin amber

Mesosmicrips sunae Lyubarsky et Perkovsky sp.nov. is herein described from ca. 99 Ma mid-Cretaceous amber from Myanmar (Kachin State). It is the second species of Mesosmicrips described from Kachin amber. The new species differs from the type species of the genus and the hitherto only known congener by the very slightly elongate pronotum which is 1.1 times as long as wide, the absence of the short grooves on posterior fourth of pronotum, the obtuse posterolateral angles of pronotum, the protibiae parallel-sided in distal quarter, the length of the protibia being 5 times greater than width, and the longer elytra leaving only two apical visible tergites exposed. The tarsal formula (5-5-5) is characteristic for both Eocene and Cretaceous family members.

Two new species and new material of the family Evaniidae (Hymenoptera: Evanioidea) from the mid-Cretaceous amber of Northern Myanmar

Two new species, Sorellevania rara Li, Shih & Ren, sp. nov. and Iberoevania nova Li, Shih & Ren, sp. nov., and a new specimen of Cretevania bechlyi Jennings, Krogmann & Mew, 2013 are described and illustrated respectively from two male and one female specimens preserved in the mid-Cretaceous Kachin amber. Sorellevania rara sp. nov. is the third species of the genus Sorellevania Engel, 2006. The placement of the new specimen in the latter genus is supported by its small body size, its elbowed antenna, and its forewing venation (e.g., the shape of the medial cells). Iberoevania nova sp. nov. is assigned to Iberoevania based on its forewing with five enclosed cells, the crossveins 2r-m, and 2m-cu absent while 1rs-m is present, and its long petiole (about half the length of the gaster). A map of the deposits yielding Evaniidae during the Cretaceous and a histogram of Evaniidae species and genus diversity during the Cretaceous and Cenozoic are provided.

A new genus and species of the Nabidae (Hemiptera, Heteroptera, Cimicomorpha) from mid-Cretaceous amber of Northern Myanmar

A new genus and species of fossil Nabidae, Feroculipodus obtusidentatus gen. et sp. nov., is described from mid-Cretaceous amber, which represents the second fossil record of Nabidae from Myanmar and is classified under the subfamily Prostemmatinae. The new species is distinguished from other nabids based on the pronotum not clearly divided into an anterior and a posterior part, fore femur with an obtuse angular process on the ventral surface, basal cell on membrane absent. Research on the newly discovered fossil specimen as a source of character information, provides us with a new perspective to analysis the phylogenetic relationships of Nabidae through external morphological characters.

Brevipronotum neli gen. et sp. nov., a new amnestine cydnid burrowing bug from mid-Cretaceous amber of northern Myanmar (Hemiptera: Cydnidae: Amnestinae)

Brevipronotum neli gen. et sp. nov., the eighth species belonging to the Cydnidae from the Burmese amber is characterised, illustrated and described. The discovery of this fossil burrowing bug, further demonstrates the biodiversity richness of the Myanmar mid-Cretaceous amber.

Further mysteries solved in Mysteriomorphidae (Coleoptera: Elateroidea) from mid-Cretaceous amber of northern Myanmar: Discovery of female specimens, and synonymy of Trapezioceps recently described as Cantharidae

The beetle family Mysteriomorphidae (Coleoptera: Elateroidea) was recently described based on a single species from the mid-Cretaceous Burmese amber. Only six specimens of an unknown sex were reported in previous studies. Here, for the first time, we examine female specimens of Mysteriomorphus Alekseev and Ellenberger, 2019 for which we describe the morphology of the ovipositor and report striking differences between them in several diagnostic characters. Additionally, we synonymize the recently described genus Trapezioceps Qu, Jarzembowski and Luo, 2023, syn. nov. with Mysteriomorphus. The monospecific Trapezioceps, also known only from Burmese amber, was erroneously classified in Cantharidae. We tentatively keep the species originally described in Trapezioceps valid, hence Mysteriomorphidae currently contain two described species: M. pelevini Alekseev and Ellenberger, 2019 and M. longelytrus (Qu, Jarzembowski and Luo, 2023), comb. nov. Based on the new findings, we discuss the morphology, variability, and diversity of Mysteriomorphus.

A striking new XXL-size flat bug from mid-Cretaceous Burmese amber: Archemezira nuoyichenae sp. nov. (Heteroptera, Aradidae)

The mid-Cretaceous amber deposits in Northern Myanmar yielded to date eleven genera and 14 species of the flat bug family Aradidae. A remarkable large female specimen of a flat bug shares basic characters of the genus Archemezira is supposed to represent a female taxon of this genus and is described and figured herein as Archemezira nuoyichenae sp. nov.

New amber records of Burmusculidae (Hymenoptera) from mid-Cretaceous Myanmar

Two new species, Burmusculus flexus sp. nov. and Burmusculus mutatus sp. nov. of Burmusculus Zhang and Rasnitsyn, 2018 in Burmusculidae, are described from the mid-Cretaceous amber of northern Myanmar. A key to all seven species of Burmusculus and detailed comparisons among the species are provided. Veins 1-Rs, 1-M, 1cu-a, 2m-cu and 2-Rs with different states suggest interspecific diagnostic characters within Burmusculus.

A new genus and a new species of pygmy mole cricket from mid-Cretaceous amber in North Myanmar (Orthoptera: Caelifera: Tridactyloidea).

This paper describes a new genus with a new species from Burmese amber, namely: Latedactylus longapedi gen. et sp. nov. (Tridactylidae: Tridactylinae). L. longapedi gen. et sp. nov. is erected based on the cylindrical second segment of cercus longer and distinctly slender than the first; metatibia without swimming plates; metatarsus about three times as long as apical spurs of metatibia.