Myanmar Amber Research Articles

New Cretaceous antlion-like lacewings promote a phylogenetic reappraisal of the extinct myrmeleontoid family Babinskaiidae

Babinskaiidae is an extinct family of the lacewing superfamily Myrmeleontoidea, currently only recorded from the Cretaceous. The phylogenetic position of this family is elusive, with inconsistent inferences in previous studies. Here we report on three new genera and species of Babinskaiidae from the mid-Cretaceous Kachin amber of Myanmar, namely Calobabinskaia xiai gen. et sp. nov., Stenobabinskaia punctata gen. et sp. nov., and Xiaobabinskaia lepidotricha gen. et sp. nov. These new babinskaiids are featured by having specialized characters, such as the rich number of presectoral crossveins and the presence of scaly setae on forewing costal vein, which have not yet been found in this family. The exquisite preservation of the Kachin amber babinskaiids facilitate a reappraisal of the phylogenetic placement of this family based on adult morphological characters. Our result from the phylogenetic inference combining the data from fossil and extant myrmeleontoids recovered a monophyletic clade composed of Babinskaiidae and another extinct family Cratosmylidae, and further assigned this clade to be sister group to a clade including Nemopteridae, Palaeoleontidae, and Myrmeleontidae. Babinskaiidae appears to be a transitional lineage between Nymphidae and advanced myrmeleontoids, with ancient morphological diversification.

Tropidogyne euthystyla sp. nov., a new small-flowered addition to the genus from mid-Cretaceous Myanmar amber

Tropidogyne euthystyla, described here, is the fourth species of this fossil genus to have been reported from amber deposits in northern Myanmar. The species are alike in features of the calyx, the shape and venation of the inferior ovary, and the absence of petals. They differ in the number and form of the styles, the lobing of the epigynous disc, and whether the flowers are apparently bisexual or unisexual. In the one species for which several flowers are available for study, T. pentaptera, floral diameters vary from 3.5 to 5.0 mm. The present species, known only from a single flower, is the smallest in the genus, with a floral diameter of only 2 mm. It differs from the 3 previously described species in having 2 stout, erect styles bearing a terminal stigma, whereas the other species have 2 or 3 short or long, arching styles that are decurrently stigmatic along the adaxial surface.

Split-footed lacewings declined over time: indications from the morphological diversity of their antlion-like larvae

Nymphidae, the group of split-footed lacewings, is a rather species-poor group. Split-footed lacewings nowadays are restricted to Australasia, while fossil forms are also known from other areas of the world, indicating that the group was more species-rich and therefore likely diverse in the past. Split-footed lacewings have rather distinct larvae, roughly resembling antlion larvae, but differing from the latter especially with regard to the mandibles. Antlion larvae usually have three prominent teeth on each mandible, while at least extant larvae of split-footed lacewings only have a single prominent tooth per mandible. Fossils interpreted as larvae of split-footed lacewings are well known from amber from Myanmar (ca. 100 myr; Burmese amber) and by a single specimen from Baltic amber (about 40 myr). We here report additional fossil specimens from Myanmar amber, expanding the known record of fossil forms from six depicted specimens to 15. For the extant fauna, we could compile 25 larvae. We compare the diversity of shape of extant and fossil larvae through time using an outline analysis (based on elliptic Fourier transformation) of the head. The results of this analysis indicate that the morphological diversity, or disparity, of split-footed lacewing larvae was higher in the past than it is today. With this type of analysis, we can show a loss of diversity over time, without the necessity to identify the fossil larvae down to a narrow taxonomical range. A similar pattern has already been recognised in silky lacewings, Psychopsidae. This might indicate a general loss of diversity of lacewing larvae.

New specimens from Mid-Cretaceous Myanmar amber illuminate the phylogenetic placement of Lagonomegopidae (Arachnida: Araneae)

Abstract New lagonomegopid spiders are described from Mid-Cretaceous Myanmar (Burmese) amber. Two new genera and species based on single specimens, Scopomegops fax gen. & sp. nov. and Hiatomegops spinalis gen. & sp. nov. are described. Two specimens belonging to Lineaburmops beigeli are further described. Additionally, after re-examining the holotype of Odontomegops titan, a detailed description of its basal ventral abdomen is added here. A phylogenetic analysis was performed to investigate the phylogenetic placement of Lagonomegopidae. A matrix of 79 morphological characters, scored for six lagonomegopid taxa and 26 non-lagonomegopid taxa, was analysed through parsimony and Bayesian phylogenetic inference. Our results recover extant Palpimanoidea as a monophyletic group and partly suggest that Lagonomegopidae is the sister-group to extant Palpimanoidea. The external sexual organs, retrolateral tibial apophysis on the male palp and tracheal spiracle in lagonomegopids are discussed.

Drawing the Excalibur bug from the stone: adding credibility to the double-edged sword hypothesis of coreid evolution (Hemiptera, Coreidae).

A new genus and species of exaggerated antennae Coreidae is described from Myanmar amber of the Late Cretaceous (Cenomanian stage). Ferriantennaexcaliburgen. et sp. nov. appears related to another Cretaceous coreid with exaggerated antennae, Magnusantenna Du & Chen, 2021, but can be differentiated by the fourth antennal segment which is short and paddle-like, the undulating shape of the pronotum and mesonotum, and the shorter and thicker legs. The new coreid, with elaborately formed antennae and simple hind legs instead of the typical extant coreid morphology with simple antennae and elaborately formed hind legs, begs the question: why were the elaborate features of the antennae lost in favor of ornate hind legs? Features that are large and showy are at higher risk of being attacked by predators or stuck in a poor molt and subjected to autotomy and are therefore lost at a higher rate than simple appendages. We hypothesize that because elaborate antennae play an additional significant sensory role compared to elaborate hind legs, that evolutionarily it is more costly to have elaborate antennae versus elaborate hind legs. Thus, through the millenia, as coreid evolution experimented with elaborate/ornate features, those on the antennae were likely selected against in favor of ornate hind legs.

Unusual morphology in the mid-Cretaceous lizard Oculudentavis

Oculudentavis khaungraae was described based on a tiny skull trapped in amber. The slender tapering rostrum with retracted narial openings, large eyes, and short vaulted braincase led to its identification as the smallest avian dinosaur on record, comparable to the smallest living hummingbirds. Despite its bird-like appearance, Oculudentavis showed several features inconsistent with its original phylogenetic placement. Here, we describe a more complete specimen that demonstrates Oculudentavis is actually a bizarre lizard of uncertain position. The new specimen is described as a new species within the genus Oculudentavis. The new interpretation and phylogenetic placement highlight a rare case of convergent evolution in skull proportions but apparently not in morphological characters. Our results re-affirm the importance of Myanmar amber in yielding unusual taxa from a forest ecosystem rarely represented in the fossil record.

X‐ray microtomography and phylogenomics provide insights into the morphology and evolution of an enigmatic Mesozoic insect larva

AbstractFossils sometimes show unusual morphological features absent in living organisms, making it difficult to reconstruct both their affinity and their function. We describe here a new lacewing larva, Ankyloleon caudatus gen. et sp.n. (Neuroptera) from the Cretaceous amber of Myanmar, characterized by an abdomen unique among insects, with ‘tail‐like’ terminal segments bearing a ventral pair of vesicles. Phase‐contrast X‐ray microtomography reveals that these structures were dense and equipped with a median duct, suggesting that they were likely pygopods used for locomotion, holding the position through adhesive secretions. Our phylogenetic analyses, combining genomic and morphological data from both living and fossil lacewings, proved critical to placing Ankyloleon gen.n. on the lacewing tree of life as an early representative of the antlion clade, Myrmeleontiformia. These results corroborate the view that derived myrmeleontiform lacewings ‘experimented’ with unusual combinations of features and specializations during their evolutionary history, some of which are now lost.Zoobank registration: urn:lsid:zoobank.org:pub:0C0AC565‐1AC9‐42CC‐831D‐EDA38BA36F64

Mass occurrence of small isopodan crustaceans in 100-million-year-old amber: an extraordinary view on behaviour of extinct organisms

Within Isopoda (woodlice and relatives), there are lineages characterised by a parasitic lifestyle that all belong to Cymothoida and likely form a monophyletic group. Representatives of Epicaridea (ingroup of Cymothoida) are parasitic on crustaceans and usually go through three distinct larval stages. The fossil record of Epicaridea is sparse and thus little is known about the palaeoecology and the origin of the complex life cycle of modern epicarideans. We present an assemblage of over 100 epicarideans preserved in a single piece of Late Cretaceous Myanmar amber. All individuals are morphologically similar to cryptoniscium stage larvae. The cryptoniscium stage usually constitutes the third and last larval stage. In modern representatives of Epicaridea, the cryptoniscium larvae are planktic and search for suitable host animals or adult females. These fossil specimens, though similar to some extant species, differ from other fossil epicaridean larvae in many aspects. Thus, a new species (and a new genus), Cryptolacruma nidis, is erected. Several factors can favour the preservation of multiple conspecific animals in a single piece of amber. However, the enormous density of epicarideans in the herein presented amber piece can only be explained by circumstances that result in high local densities of individuals, close to the resin-producing tree.

Two new mid-Cretaceous caddisflies (Trichoptera, Philopotamidae) from amber of Northern Myanmar

Two new species of caddisflies, Wormaldia diplobifurca sp. nov. and Wormaldia denticulata sp. nov. in Philopotamidae, are described based on two well-preserved specimens from mid-Cretaceous amber of Myanmar. Haustellum of Wormaldia denticulata sp. nov. bearing granules with tubercles on its surface indicates that this type of haustellum was developed in the mid-Cretaceous. These two new species with the absence or only one comb on their tibial spurs confirm that tibial spur with two combs is probably a derived character. By comparing the characters of forewing and genitallia, the mid-Cretaceous fossil caddisflies of Wormaldia genus can be divided into at least three groups of species, but none of these fossil species can be assigned into the extant species of Wormaldia.

New genus and species of Tettigarctidae (Hemiptera: Cicadomorpha: Cicadoidea) from the mid-Cretaceous amber of northern Myanmar

A new genus and species of Tettigarctidae, Burmaprosbole nervosa gen. et sp. nov., with well-preserved wings is described from the mid-Cretaceous Myanmar amber. It can be distinguished from the other genera by its tegmen M with six branches, M 3+4+5+6 strongly arched after nodal line, basal of M and CuA connecting by a relatively long cross vein, basal cell pentagonal, medial cell short and wide. Based on the fossil records of Tettigarctidae, we consider it is inappropriate to use the number of R branches as a diagnostic character in tettigarctids’ higher categories (superfamilies or tribes).

New species of Hybristodryinus from mid-Cretaceous Myanmar amber (Hymenoptera, Dryinidae)

A new species of the genus Hybristodryinus Engel, 2005, Hybristodryinus viriosus sp. nov., is described from the mid-Cretaceous Myanmar (Burmese) amber based on a well-preserved female specimen. The keys to fossil species of Hybristodryinus is modified. The new species is most similar to Hybristodryinus mon Perkovsky, Olmi, Müller and Martynova, 2019, but the distance between inner edge of the lateral ocelli is much longer than the distance from the posterior edge of the lateral ocellus to the occipital carina, and which is also much longer than the distance between the inner edge of a lateral ocellus and the median ocellus. This new finding not only broadens the diversity of Dryinidae, but also provides important morphological characters, especially the well-preserved details of the chelate protarsus used for capturing hosts, to enhance our understanding of Hybristodryinus.

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

Simple SummaryThe mid-Cretaceous amber of Myanmar (also known as Burmese amber) is almost 100 MYA old and represents an invaluable source of information about the evolution of life in the late Mesozoic. This is particularly true for the early flies (lower Diptera) which underwent rapid radiation during the Cretaceous period. Here we describe a remarkable nematocerous fossil fly which shows a character typical of the flies of the suborder Brachycera—with strongly modified antenna—representing new evidence that such a Brachycera-like modification of the antennae has evolved several times during the evolutionary history of Diptera.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).

Discovery of Lebambromyia in Myanmar Cretaceous Amber: Phylogenetic and Biogeographic Implications (Insecta, Diptera, Phoroidea).

Simple SummaryPhoroid flies are an ancient lineage of Diptera, which includes megadiverse, widespread groups like the scuttle flies, as well as species-poor, sometimes relict, groups like flat-footed and ironic flies. The earliest fossils of phoroid flies are from Early Cretaceous. In this paper we describe a second species of the enigmatic phoroid fly genus Lebambromyia. The genus was erected to accommodate an extinct species, L. acrai Grimaldi and Cumming, from Lebanese amber deposit, dated at ca. 120 Mya. A new species, L. sacculifera sp. nov., is described here based on a single female specimen embedded in Myanmar “mid-Cretaceous” amber, which is over 20 Ma younger than the Lebanese outcrop, implying that this genus had a wide geographic and temporal distribution. The state of preservation of the new specimen and its study with phase contrast X-ray microtomography show that this ancient fly was characterized by a mix of ancient and modern features, such as specialized sensory areas in the antenna. Phylogenetic analyses support that Lebambromyia was related to flat-footed and ironic flies, but a clear phylogenetic position remains elusive.Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myanmar, integrating traditional observation techniques and X-ray phase contrast microtomography. Lebambromyia sacculifera is the second species of Lebambromyia after L. acrai Grimaldi and Cumming, described from Lebanese amber (Early Cretaceous), and the first record of this taxon from Myanmar amber, considerably extending the temporal and geographic range of this genus. The new specimen bears a previously undetected set of phylogenetically relevant characters such as a postpedicel sacculus and a prominent clypeus, which are shared with Ironomyiidae and Eumuscomorpha. Our cladistic analyses confirmed that Lebambromyia represented a distinct monophyletic lineage related to Platypezidae and Ironomyiidae, though its affinities are strongly influenced by the interpretation and coding of the enigmatic set of features characterizing these fossil flies.

EmEminepygia/em emmyanmarensis/em sp. nov., a new Earwig (Dermaptera) Nymph in Burmese Amber.

A new fossil earwig nymph, Eminepygia myanmarensis gen. et sp. nov. (Pygidicranidae), from the mid-Cretaceous amber of Myanmar, is described and figured. Eminepygia myanmarensis gen. et sp. nov. can be readily distinguished from all other extinct and recent members of Dermaptera by the prominent bulges on the last three terga. Our new finding sheds further light on the diversity and morphological disparity of fossil dermapterans during the Late Mesozoic.

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

Simple SummaryBruchomyiinae is one of seven subfamilies of Psychodidae. In the contemporary fauna, this small, relict subfamily occurs mainly in tropical and sub-tropical regions. Examination of inclusions preserved in the Upper Cretaceous amber of Myanmar (also known as Burmese amber), which is almost 100 mya, shows that this subfamily was abundant during the Cretaceous period. The extinct genus Palaeoglaesum is known only from this fossil resin. Moreover, its numerous inclusions and high diversification confirm that the Mesozoic was the stage of the early evolution and radiation of Psychodidae. Here we describe three new species and we provide additional details regarding the morphology of fossil species.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., Skibińska and Krzemiński P. teres sp. nov. Skibińska and Albrycht, and P. pilosus sp. nov. Skibińska, Krzemiński 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.

New amber record of Braconidae (Insecta: Hymenoptera) from the mid-Cretaceous of Myanmar

Protorhyssalinae is an extinct, Cretaceous-only subfamily of braconid wasps hitherto comprising 7 genera and 7 species in its widest acceptance. A new genus Burmabracon gen. nov. with two new species, B. gracilens sp. nov. and B. grossus sp. nov. from the mid-Cretaceous Myanmar (Burmese) amber, are described and assigned to Protorhyssalinae, based on the following characters: head orthognathous and almost certainly cyclostome, antenna with more than 20 antennomeres, notauli complete, forewing with 2m-cu absent and hind wing with 1r-m and Cu present. The Mesozoic fossil record of the Braconidae suggests that the family originated in or before the Early Cretaceous.

Morphological phylogenetics provide new insights into the classification and evolution of fossil soldier beetles from Mid-Cretaceous Burmese amber (Coleoptera: Cantharidae)

AbstractCantharidae is a diverse group of soft-bodied beetles and frequently occurs in the Mid-Cretaceous (c. 99 Mya) amber of Myanmar. In the present paper, three new soldier beetles, Cretocantharis veda gen. & sp. nov., Palaeocantharispanna gen. & sp. nov. and Hukawngichthyurus maha sp. nov. are reported. A phylogenetic reconstruction of Cantharidae, including all extant subfamilies and tribes, corroborates a distinct lineage comprising cantharine-like cantharids from Burmese amber as sister to Silini (Silinae), revealing that the current subfamilial placement is probably inadequate. Together with our results and recent molecular phylogenetic frameworks, it reveals that subfamilies of Cantharidae evolved during the Cretaceous period and highlights a probable Gondwanan ancestry of main cantharid groups. Our topology also proposes that the systematically controversial tribe Tytthonyxini of Silinae constitutes an independent clade sister to Malthininae, rather than the component of Silinae. Furthermore, Archaeomalthodes rosetta, previously placed in Malthininae, is recovered as a member of Dysmorphocerinae, representing the oldest fossil record for this subfamily and enhancing the Gondwanan origin hypothesis of Burmese amber biota. The previous interpretation of reticulated elytra as a lycid-mimicry for the Cretaceous cantharid fossils and pleisiomorphy of Cantharidae are challenged and discussed.

A 100 million-year-old armoured caterpillar supports the early diversification of moths and butterflies

The lepidopteran caterpillar is a ubiquitous type of larva with a significant impact on the modern ecosystem. Quite on the contrary, the fossil record of caterpillars is quite scarce, with four occurrences in Cretaceous ambers representing the oldest ones. Here we report a new specimen from 100 million-year-old Cretaceous Myanmar amber. The caterpillar has appendages on abdomen segments 3–6 and 10. Such an arrangement is today only known in caterpillars of the group Gracillariidae. These caterpillars are usually dorso-ventrally flattened, adapted for leaf mining. The fossil specimen does not appear flattened and is additionally armoured with spines dorsally on the trunk segments. All other known Cretaceous larvae are “naked”, lacking dorsal armature. The new specimen hence increases the diversity of Cretaceous caterpillars. This finding is congruent with recent phylogenetic reconstructions and hence supports an early diversification of the group Lepidoptera.

A brachypterous cockroach (Dictyoptera: Blattaria: Blattoidea) and its potential relevance to the palaeoenvironment of mid-Cretaceous Myanmar amber locality

A second blattoid species, Cercoula brachyptera gen. et sp. nov. is described from Cretaceous amber. It is placed in Blattoidea because of the combination of bivalvate female subgenital plate and type-A forefemoral spination. Its relatively small size, and small, slender, pod-like cerci, suggest that the new species is a stem member of Blattoidea. Cercoula brachyptera is the first fossil of brachypterous cockroach. Since wing reduction might be a response of cockroaches to the arid environment, C. brachyptera might indicate an arid microenvironment or a dry season, or even contribute to the possibility of an arid palaeoclimate of the Myanmar amber locality.

Valviloculus pleristaminis gen. et sp. nov., a Lauralean fossil flower with valvate anthers from mid-Cretaceous Myanmar amber

The flower described here as Valviloculus pleristaminis, a new genus and species of fossil angiosperms, was obtained from Myanmar amber deposits dating to the mid-Cretaceous period. The flower is staminate, with an ovoid, hollow floral cup. The perianth consists of 6 tepals, one of which was lost prior to preservation. Numerous helically arranged stamens are borne at the summit of the flower. The anthers are bilocular, with pollen sacs that dehisce by laterally hinged valves. The tip of the connective bears a cup-shaped appendage. The gynoecium is represented only by a cluster of vestigial styles centered among the stamens. The fossil is provisionally assigned to order Laurales, its closest affinities being with the families Monimiaceae and Atherospermataceae.