Amber Inclusions Research Articles

False scorpions (Arachnida, Pseudoscorpiones) from Lower Cretaceous Spanish amber

AbstractPseudoscorpions, one of the earliest terrestrial lineages dating back to the Middle Devonian period (c. 385 Ma), have a limited fossil record mainly as inclusions in amber. The available fossils are mostly from the Cenozoic era, making it challenging to comprehensively understand their evolutionary history and diversification over time. Here, we report the first fossils of the order from Spanish Lower Cretaceous (upper Albian) ambers. Two new genera and species in the family Garypinidae are described from Álava amber (Peñacerrada II outcrop, Álava Province): Cretogarypinus zaragozai gen. et sp. nov. and Ithioreolpium alavensis gen. et sp. nov. Remarkably, the holotype of Cretogarypinus zaragozai shows preservation of internal soft tissues. The variability observed in the arolium of both fossil garypinids serves as compelling evidence for the hypothesis of diphyletism within the clade, which was already well established before the Early Cretaceous. Additionally, an incomplete specimen consisting of an isolated palp ascribed to the family Pseudogarypidae (extant genus Pseudogarypus Ellingsen), is described from San Just amber (Teruel Province). These findings represent the earliest occurrences of the families Garypinidae (superfamily Garypinoidea) and Pseudogarypidae (superfamily Feaelloidea) in the fossil record. They not only contribute to our understanding of a diverse pseudoscorpion fauna in Spanish amber but also offer valuable insights into divergence time estimations for pseudoscorpion families and potentially for biogeographic studies.

A re-assessment of Palaeotanyrhina (Hemiptera: Heteroptera) elucidates the phylogeny of Leptopodoidea

Abstract A morphologically unusual fossil true bug genus, Palaeotanyrhina Poinar, Brown & Kóbor, 2022, placed into Cimicomorpha: Reduvioidea by its authors, is revisited based on an inclusion in mid-Cretaceous Burmese amber. The original description is supplemented with additional details and corrections. It is demonstrated that the placement of Palaeotanyrhina into Cimicomorpha was based on misinterpretations of the morphology of the holotype, and the genus is a member of the infraorder Leptopodomorpha. A phylogenetic analysis is provided for fossil and extant taxa of Leptopodomorpha. Parvilepta Yu, Zhuo & Chen, 2023, Cretaleptus Sun & Chen, 2019, Macrolepta Yu, Zhuo & Chen, 2023 (currently members of Leptopodidae: Leptosaldinae) and Palaeoleptus Poinar, 2009 (the type genus of Palaeoleptidae) are demonstrated to be phylogenetically closely related to Palaeotanyrhina. All the above mentioned genera are recognized to represent stem-group members of Leptopodomorpha: Leptopodidae: Leptopodinae: Leptopodini, and accordingly, they are transferred to the latter tribe. The following new subjective synonyms are proposed: Leptopodidae: Leptopodinae: Leptopodini Brullé, 1836 = Palaeoleptidae Poinar, 2009, syn. nov. = Palaeotanyrhinidae Poinar, Brown & Kóbor, 2022, syn. nov. Based on the analytic results, the subfamilies Leptosaldinae and Leptopodinae of Leptopodidae and the tribes Leotichiini and Leptopodini of Leptopodinae are considered valid, redefined, and a list of their included genera and species are provided. Arguments are provided in support of the placement of Leptosaldinea Popov & Heiss, 2016, formerly placed into Leptosaldinae, into the infraorder Dipsocoromorpha.

Pheidole praehistorica sp. nov., a new addition to spiny ants of the genus Pheidole Westwood, 1839 (Formicidae, Myrmicinae) from Oligo–Miocene Mexican amber

A fossil species of ant, Pheidole praehistorica sp. nov. (Hymenoptera, Formicidae, Myrmicinae), is described and illustrated from the late Oligocene and early Miocene amber-bearing beds of Mexico. The type material comprises five amber inclusions from the Simojovel site in Chiapas. Pheidole praehistorica is recognized by having compound eyes positioned mesad on the head and protruded laterally from the head’s margins; pronotum long, forming a neck, with a pair of spines directed dorsolaterally; mesonotal groove deep forming a more or less U-shape concavity in lateral view; dorsal and declivitous faces of the propodeum well differentiated, comprising an approximately 90 degrees angle; propodeum with a pair of long spines; peduncle of the petiole long, as long as the spines of the propodeum. A phylogenetic analysis was also performed using Formica integroides, Camponotus chartifex, Dolichoderus spurius, Cephalotes minutus and Atta mexicana to assess the relationships of P. praehistorica with its fossil spiny congeners from Dominican amber and closely related extant species. The results show close morphological and phylogenetic affinities between the fossil ant P. praehistorica with P. primigenia and P. tethepa from Dominican amber, which may suggest that the shared spinescence character in Pheidole has a probable New World ancestry. The new record of P. praehistorica in the Oligo–Miocene strata of southernmost North America provides further evidence for the ancient distribution of spiny ants of the genus Pheidole in the New World.

Characters of a new species of the Cretaceous genus †Loeblitoides affirm affinities to the extant 'Syndicus group' of Stenichnini (Coleoptera: Staphylinidae: Scydmaeninae).

A new species of Cenomanian Stenichnini is described, based on an inclusion in Myanmar amber: †Loeblitoides latus sp. nov. As a close relationship between †Loeblitoides and the extant genera Syndicus Motschulsky, Loeblites Franz, and Horaeomorphus Schaufuss was postulated, we used 3D visualization techniques based on micro-computed tomography to search for otherwise impossible to observe morphological details and find arguments supporting this hypothesis. A novel structure, a pair of basal elytral foveae connected in a peculiar way, found in †L. latus, indeed supports the previous views, as it is unique for the extant 'Syndicus group'. The diagnosis of †Loeblitoides is emended to include new findings.

First record of Nicobium LeConte (Coleoptera: Ptinidae: Anobiinae) from Baltic amber with the description of a new extinct species.

The first extinct Paleogene species of the Anobiinae genus Nicobium LeConte, 1861 is described based on an inclusion in Baltic amber. Two characteristic features distinguishing the extinct species (among other characters present in one combination or another in extant species) are sparse, inconspicuous elytral pubescence and rectangular, sharp posterior pronotal angles. The new species, Nicobium necrocrator sp. nov., is just the second described extinct representative of the genus. Its discovery adds to our knowledge of the diversity of deathwatch beetles in the amberiferous forests of the Eocene-and establishes an important reference point for future studies of the origin and distribution of these wood-boring beetles living millions of years ago.

Cretaceous amber inclusions illuminate the evolutionary origin of tardigrades

Tardigrades are a diverse phylum of microscopic invertebrates widely known for their extreme survival capabilities. Molecular clocks suggest that tardigrades diverged from other panarthropods before the Cambrian, but their fossil record is extremely sparse. Only the fossil tardigrades Milnesium swolenskyi (Late Cretaceous) and Paradoryphoribius chronocaribbeus (Miocene) have resolved taxonomic positions, restricting the availability of calibration points for estimating for the origin of this phylum. Here, we revise two crown-group tardigrades from Canadian Cretaceous-aged amber using confocal fluorescence microscopy, revealing critical morphological characters that resolve their taxonomic positions. Formal morphological redescription of Beorn leggi reveals that it features Hypsibius-type claws. We also describe Aerobius dactylus gen. et sp. nov. based on its unique combination of claw characters. Phylogenetic analyses indicate that Beo. leggi and Aer. dactylus belong to the eutardigrade superfamily Hypsibioidea, adding a critical fossil calibration point to investigate tardigrade origins. Our molecular clock estimates suggest an early Paleozoic diversification of crown-group Tardigrada and highlight the importance of Beo. leggi as a calibration point that directly impacts estimates of shallow nodes. Our results suggest that independent terrestrialization of eutardigrades and heterotardigrades occurred around the end-Carboniferous and Lower Jurassic, respectively. These estimates also provide minimum ages for convergent acquisition of cryptobiosis.

A new Malthinus (Coleoptera: Cantharidae: Malthininae) adds to the unrivaled diversity of arthropods found in Eocene Baltic amber.

A new species of soldier beetle (Cantharidae) from Eocene Baltic amber, Malthinus fabriziofantii sp. nov., is described and illustrated. This is yet one more species of Cantharidae documented from the Baltic deposit, a rich accumulation of amber that provides an unparalleled view of Eocene arthropods with more than 3,000 species discovered to date. Creating this remarkable deposit was a favorable blend of environmental elements that included a humid, warm climate; an assortment of different habitats; and conifer trees exuding profuse amounts of resin that trapped hundreds of thousands of insects, arachnids, and other small organisms that would become amber inclusions.

New genus and species of ponerine ant (Hymenoptera: Formicidae) from Mexican amber

ABSTRACT A new genus and species of ponerine ant from Mexican amber, Siinikaponera sulimata, is described and illustrated. The type material is an amber inclusion from the Montecristo mine in Chiapas, Mexico, which dates back to the Oligo-Miocene period. Siinikaponera sulimata gen. et sp. nov. shares traits with other ants in the subfamily Ponerinae, including the outer edges of the frontal lobes forming simple short semicircles or blunt triangles, presence of promesonotal suture, meso- and metatibia with 0–2 spurs, antenna with 12 segments, constriction between the first and second gastral tergite well impressed, presence of sting, complete wing venation, and complete cell patterns. Siinikaponera sulimata gen. et sp. nov. also has unique features that separate it from other ponerine ants, such as fore, middle and hind tibiae with two spurs each, anterior margin of clypeus with two anteriorly projecting lobes, mandible dentition pattern, posterior peduncle of petiole long, and presence of relatively long coxae. A distinctive feature of Siinikaponera sulimata gen. et sp. nov. is the presence of two projecting lobes on the anterior clypeal margin, a plesiomorphic character shared with the genus Dinoponera. Accordingly, this new fossil record offers valuable insights into the worldwide diversity and distribution of ponerine ants.

Interaction between spiders and ticks—ancient arthropod predatory behavior?

Ticks are ectoparasite vectors of pathogens affecting human and animal health worldwide. Rational integration of different control interventions including plant-derived repellents and acaricides, management of natural predators, and vaccines is required for innovative approaches to reduce the risks associated with ticks and tick-borne diseases. How tick populations are naturally controlled is always a question. Tick interactions with other arthropods including predators evolved from ancient times. In this study, Cretaceous (ca. 100 Mya) Burmese amber inclusions were identified as probably related to Compluriscutula vetulum (Acari: Ixodida: Ixodidae) tick larvae and spider silk. As illustrated in this study, ancient interactions between ticks and spiders may support arthropod predatory behavior as a natural control intervention. Rational integrative management of different tick control interventions including natural predators under a One Health perspective will contribute to effectively and sustainably reducing the risks associated with ticks and tick-borne diseases.

First fossil record of false stag beetles (Coleoptera: Scarabaeoidea: Diphyllostomatidae): Evolutionary and biogeographical implications

The monogeneric scarabaeoid family Diphyllostomatidae contains only three extant false stag beetle species, all of which are restricted to California, USA. In this study, a fossil specimen newly found in mid-Cretaceous Kachin amber of northern Myanmar is putatively assigned to this family, here described as Prodiphyllostoma inexpectatum gen. et sp. nov. The discovery of this rare scarabaeoid as a Mesozoic amber inclusion from Myanmar is significant in consideration of the paleobiogeography and evolutionary history of this family.

Extinct and extant termites reveal the fidelity of behavior fossilization in amber

Fossils encompassing multiple individuals provide rare direct evidence of behavioral interactions among extinct organisms. However, the fossilization process can alter the spatial relationship between individuals and hinder behavioral reconstruction. Here, we report a Baltic amber inclusion preserving a female-male pair of the extinct termite species Electrotermes affinis. The head-to-abdomen contact in the fossilized pair resembles the tandem courtship behavior of extant termites, although their parallel body alignment differs from the linear alignment typical of tandem runs. To solve this inconsistency, we simulated the first stage of amber formation, the immobilization of captured organisms, by exposing living termite tandems to sticky surfaces. We found that the posture of the fossilized pair matches trapped tandems and differs from untrapped tandems. Thus, the fossilized pair likely is a tandem running pair, representing the direct evidence of the mating behavior of extinct termites. Furthermore, by comparing the postures of partners on a sticky surface and in the amber inclusion, we estimated that the male likely performed the leader role in the fossilized tandem. Our results demonstrate that past behavioral interactions can be reconstructed despite the spatial distortion of body poses during fossilization. Our taphonomic approach demonstrates how certain behaviors can be inferred from fossil occurrences.

The evolutionary history of Coleoptera (Insecta) in the late Palaeozoic and the Mesozoic

AbstractRecent progress in beetle palaeontology has incited us to re‐address the evolutionary history of the group. The Permian †Tshekardocoleidae had elytra that covered the posterior body in a loose tent‐like manner. The formation of elytral epipleura and a tight fit of elytra and abdomen were important evolutionary transformations in the Middle Permian, resulting in a tightly enclosed subelytral space. Permian families were likely associated with dead wood of gymnospermous trees. The end‐Permian extinction event resulted in a turnover in the composition of beetle faunas, especially a decline of large‐bodied wood‐associated forms. Adephaga and Myxophaga underwent a first wave of diversification in the Triassic. Polyphaga are very rare in this period. The first wave of diversification of this suborder occurs in the Jurassic, with fossils of Elateriformia, Staphyliniformia and Cucujiformia. The Cretaceous fossil record has been tremendously enriched by the discovery of amber inclusions. Numerous fossils represent all major polyphagan lineages and also the remaining suborders. Improved analytical methods for documenting and placing extinct taxa are discussed. Different factors have played a role in the diversification of beetles. The enormous number of species associated with flowering plants, and timing and patterns of diversification in phytophagous lineages indicate that the angiosperm radiation played a major role in beetle macroevolution. Moreover, the evolution of intimate partnerships with symbionts and the acquisition of novel genes—obtained from fungi and bacteria via horizontal gene transfers—facilitated the use of plant material as a food source and were key innovations in the diversification of plant‐feeding beetles.

First flower inclusion and fossil evidence of Cryptocarya (Laurales, Lauraceae) from Miocene amber of Zhangpu (China)

Lauraceae have one of the oldest fossil records of angiosperms with the earliest known evidence from the mid-Cretaceous. However, most of these records are based on leaves, especially from the Cenozoic of Asia, which are often challenging to assign to extinct or extant genera or species. In contrast, fossils of reproductive organs are more informative, but remain scarce. We here described the first Cenozoic Lauraceae flower of Asia and confirmed the presence of Cryptocarya in the Miocene Zhangpu flora (Fujian Province, south-eastern China) based on an amber inclusion. We scanned the specimen using synchrotron radiation-based micro-computed tomography (SRμCT) and then compared the fossil with extant flowers of the genus. The present fossil flower is small, bisexual, and polysymmetric, with a whorled and trimerous perianth and androecium along with a hypanthium around the gynoecium. The perianth comprises six undifferentiated tepals, the androecium consists of nine stamens and three innermost staminodes, and the gynoecium of a single carpel with a superior, unilocular (and uniovulate) ovary. Our study also shows that the fossil shares an unusual position of the typical staminal glands and a short androecial tube on the rim of the hypanthium with at least one extant Australian species of Cryptocarya, which have not been reported before. Nowadays, Lauraceae are still present in tropical to subtropical regions, mostly in American and Asian rainforests. The discovery of many Lauraceae leaf fossils in Zhangpu, as well as the amber flower of this study, is consistent with the current reconstruction of the amber source environment as a megathermal seasonal rainforest during the Mid-Miocene.

Two new species of Tasiocera Skuse from Baltic amber (Diptera, Limoniidae)

The paper presents very rare fossil record of crane flies. Inclusions in Baltic amber have documented the second evidence of the existence of the genus Tasiocera (Diptera: Limoniidae: Chioneinae) in ancient epochs of Earth’s history. Hypotheses were also introduced regarding the environmental preferences of fossil Dasymolopilus in relation to modern representatives of the subgenus. The genus is numerous in species and widespread in the modern fauna, while only one species, Tasiocera (Dasymolophilus) circumcincta, has been known from the fossil record to date. The paper presents an additional description and graphic documentation of this species based on new materials. The discovery of two other species Tasiocera (Dasymolophilus) gorskii sp. nov. and Tasiocera (Dasymolophilus) baltica sp. nov. in Eocene resins documents the occurence of Tasiocera since Eocene. Interestingly, only subgenus Dasymolophilus is represented both in extinct and extant fauna while subgenus Tasiocera is not known from the fossil record. The new discovery is very significant, and the result of the study adds a brick to our understanding of the evolution of this group of insects and their habitat.

The first Paleogene record of Hyperisus Mulsant and Rey (Coleoptera: Ptinidae) with description of a new species and an attempt of biogeographic analysis of ptinid assemblage in Baltic amber

ABSTRACT Based on an inclusion in Baltic amber, the first extinct species of the genus Hyperisus Mulsant and Rey, 1863 (Ptinidae: Ernobiinae: Xestobiini), namely H. carstengroehni sp. nov. is described. This new fossil Eocene species differs from extant European congeners in having the dorsal pubescence of two types; the lesser body size; the abdominal ventrite 5 punctate; the dorsal pubescence evenly dense; the antennal club longer than antennomeres 1–8 combined; and in the details of dorsal punctation. Provisional biogeographical affinities of the described Baltic amber Ptinidae (as of July 2023) are briefly analysed. All 20 extant genera known in Baltic amber (100% of analysed assemblage) still inhabit Holarctic of Recent. The ptinid assemblage of Baltic amber is almost twice closer in the composition of genera to the extant fauna of Palearctic or Nearctic than to other regions. Possible explanations are proposed for the abundance of death-watch beetles in Baltic amber.

Early Eocene biotic assemblage from the sedimentary deposits of the Tarkeshwar Lignite Mine, Gujarat and its palaeoenvironmental implications

The Palaeogene biota and the palaeoenvironmental history from the low latitudes are remarkably well–preserved in theopen–cast lignite deposits from Western India. Lignite sequences of the Cambay Shale Formation (Gujarat) have been a majorsource to understand the concept of early evolution of fossils including flora, arthropods, vertebrates fauna, and several aquaticforms during the Early Eocene. The study deals with an extensive record of amber inclusions and extracted pollen, vertebratefragments, dinoflagellate cysts and Carbon isotopes from the lignite and associated sediments from the Tarkeshwar Lignite Mineto add insights into the palaeoenvironment and depositional conditions of the Cambay Basin during the Early Eocene period. Thecurrent study demonstrates that throughout the late Palaeocene and early Eocene epoch, the palaeoenvironment changed fromlow land, marshy (lower portion), to shallow marine environment, presumably due to hyperthermal event PETM (middle part).Age diagnostic taxa, viz. Auxiodinium longispinosum, Apectodinium parvum and early wetzelielloid (Vallodinium? sp.) excursionprovide late Palaeocene–early Eocene period (~56–53 Ma) for the dinocyst interval in the middle part of the section. A pronouncednegative Carbon Isotope Excursion (CIE) in the middle part is correlated to the second Eocene Thermal maximum (53.7 Ma),which is a globally recorded hyperthermal event. During the ETM–2 warming, the rise in pCO2 caused warm, humid conditionsas well as a rise in sea level, which may have contributed to the establishment of constrained shallow marine environments in theexamined middle unit sedimentary succession. Floral (spore–pollens, leaf, wood, seed, fruits) and faunal assemblages (Crocodiles,fish remains, amber insects) revealed the prevalence of a dense tropical luxurious rain forest (floral and faunal) near shore duringthe ETM–2 in the Tarkeshwar Lignite Mines, Cambay Basin.

The first description of an apterous aphid morph of the family Canadaphididae (Hemiptera, Sternorrhyncha, Aphidomorpha).

The first apterous morph of the Canadaphididae family is described based on Canadian amber inclusions. On the basis of morphological features, it was assigned to the species Canadaphis carpenteri. For the first time, a fluorescence microscope was used to examine a representative of the Canadaphididae family, revealing previously unknown details.

First biological inclusion in Upper Cretaceous Texas amber, USA

The first biological inclusion in Cretaceous (Cenomanian) amber from Texas (USA) is here documented. Most of the Cretaceous ambers with biological inclusions are from Europe (Spain, France) and Myanmar (Asia). Although the coleopteran here reported is microscopic and incomplete, it preserves enough morphological details to be identified as a member of the Family Ptinidae Latreille, 1802. This antecedent is significative and reveals the potential of this Cretaceous amber to contain more diverse bioinclusions, since the paleoenvironment suggested by the sediments that contain the amber and the ecological affinity of recent representatives of the Ptinidae suggest a humid forest near an estuary, associated to deltaic plain deposits. Este hallazgo representa la inclusión biológica en ámbar más antigua en las Americas.

Impact of increasing morphological information by micro-CT scanning on the phylogenetic placement of Darwin wasps (Hymenoptera, Ichneumonidae) in amber

The correct interpretation of fossils and their reliable taxonomic placements are fundamental for understanding the evolutionary history of biodiversity. Amber inclusions often preserve more morphological information than compression fossils, but are often partially hidden or distorted, which can impede taxonomic identification. Here, we studied four new fossil species of Darwin wasps from Baltic and Dominican amber, using micro computed tomography (micro-CT) scans and 3D reconstructions to accurately interpret and increase the availability of morphological information. We then infer their taxonomic placement in a Bayesian phylogenetic analysis by combining morphological and molecular data of extant and fossil Darwin wasps and evaluate the impact and usefulness of the additional information from micro-CT scanning. The results show that although we gained significant morphological information from micro-CT scanning, especially concerning measurements and hidden dorsal and ventral structures, this did not impact subfamily-level placement for any of the four fossils. However, micro-CT scanning improved the precision of fossil placements at the genus level, which might be key in future dating and diversification analyses. Finally, we describe the four new fossil species as Rhyssa gulliveri sp. nov. in Rhyssinae, Triclistus levii sp. nov. in Metopiinae, Firkantus freddykruegeri gen. et. sp. nov. in Pimplinae and Magnocula sarcophaga gen. et sp. nov. in Phygadeuontinae. The first two species are the first known representatives of the subfamilies Rhyssinae and Metopiinae in amber.

First fossil record of Trichosteleum (Bryophyta: Sematophyllaceae) from mid-Miocene Zhangpu amber in Asia

The evolutionary history of terrestrial moss in Asia during the Cenozoic is poorly interpreted in largely because of very limited fossil evidence. The middle Miocene Zhangpu amber is the sole resin source of moss fossils in China, which shows a diverse moss population during the mid-Miocene Climatic Optimum. In this study, we reported the discovery of a gametophyte fragment of moss fossil in a well-preserved amber inclusion from the middle Miocene of Zhangpu, Southeast China. The observation methods involved light microscopy and synchrotron radiation–based X-ray microcomputed tomography analysis on the amber inclusions. The fossil has lanceolate leaves with involute margins, long linear laminal cells with unipapillae, well-developed and enlarged alar cells, and an absence of costae. The fossil is assigned to the extant Trichosteleum and represents the only known occurrence of a fossilized Trichosteleum member in Asia. This finding enhances our comprehension on the moss diversity within Zhangpu amber and establishes a first record of Trichosteleum in Asia.