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Life history and evolution of the enigmatic Cretaceous–Eocene Alienopteridae: A critical review
Abstract
Alienopteridae are among the most perplexing fossil insects and once conspicuous members of Cretaceous Dictyoptera (now including cockroaches, termites and mantises). However, the precise nature of their life history, evolution, and phylogenetic affinities remained controversial and open to debate. Here we report new alienopterid nymphs from mid-Cretaceous Kachin amber (approximately 99 Ma) and define three nymphal morphotypes, along with proposed interpretations of their life style. We also re-evaluate the systematic position of Alienopteridae, and of the recently erected order Aethiocarenodea. Geometric morphometric analyses suggest that morphotype I nymphs exhibit distinct morphological specializations that were most likely associated with ant mimicry, like immature stages of some modern crown mantises. Remarkably, mimetic association between these nymphs and stem-group ants provides the earliest record of ant mimicry (myrmecomorphy), which is contemporary with the earliest ants and their eusociality. We discuss different interpretations of the life history of alienopterid adults, especially wasp mimicry, and conclude that Teyia was likely a wasp mimic. The nymphs (morphotype I) and adults of Teyia resemble different models, which provides the first fossil record of transformational mimicry, implying that this behaviour had already evolved by the mid-Cretaceous. In addition, one alienopterid nymph laden with pollen clumps provides evidence for gymnosperm pollination and a previously unknown gymnosperm-insect association. This suggests that extinct dictyopterans might have been among the earliest pollinators, with a hitherto undervalued role in pollination ecology. Our phylogenetic analysis provides evidence that Alienopteridae and Umenocoleidae together constitute a monophyletic group (Alienoptera), which is placed as sister taxon of Mantodea. Alienoptera including Umenocoleidae were supported as a separate lineage, and mainly characterized by sclerotized shell-like tegmina and unique leg structures, their main diversification probably occurred before the J/K boundary, and we suggest a common evolutionary origin during the Late Jurassic.
... Over 75 species and 17 families of roaches alone have been described from this locality (Vršanský et al. 2018). They show adaptations to different lifestyles and both modern and extinct faunal complexes occur in this period (Zhang et al. 2023;Vršanský et al. 2023a,b;Vrsanský & Bechly 2015;Luo et al. 2022;Taniguchi et al. 2021;Hinkelman 2023;Kováčová 2023;Sendi 2022a,b;Li and Huang, 2023;Šmídová 2022;Šmídová et al. 2022;Grimaldi et al. 2004;Song et al. 2022). One of the reasons for this high diversity is also the location and paleoclimate of the Burmese amber localities, as they were situated on the West Burma block (a continental fragment originating from Gondwana) and probably formed on an island in a tropical biome close to the equator (Westerweel et al. 2019;Metcalfe 2017). ...
... Umenocoleidae are an extinct beetle-like family with a stratigraphical record from Early Cretaceous (Lower Barremian) to the Late Cretaceous (Turonian) and cosmopolitan distribution (Luo et al. 2022). Taxonomically they are related to Alienopteridae (Vršanský et al. 2018;Luo et al. 2022). ...
... Umenocoleidae are an extinct beetle-like family with a stratigraphical record from Early Cretaceous (Lower Barremian) to the Late Cretaceous (Turonian) and cosmopolitan distribution (Luo et al. 2022). Taxonomically they are related to Alienopteridae (Vršanský et al. 2018;Luo et al. 2022). Umenocoleids are usually relatively small, and pollen transfer between several specimens has been reported, similar as to some alienopterids (Luo et al. 2022;Sendi et al. 2020Sendi et al. , 2023Hinkelman 2020). ...
A new fossil umenocoleid from Burmese amber is described as Nigropterix cummingi sp. n. on the basis of a completely preserved adult female. The genus Nigropterix Sendi in Sendi et al. (2023) was previously only reported in Turonian sediments from Kzyl-Zhar in Kazakhstan. The herein described species differs from the latter in having parallel M, and R area with numerous cross-veins. Furthermore, the triangular shaped pronotum with unreduced paranotalia, and possibly the shortened ovipositor with punctures and minute setae are autapomorphic. The leathery texture consisting of irregular rows of bulges with small pits including setae on the forewings is very similar to Alienopterix Mlynský in Vršanský et al. (2018), Archaeospinapteryx Sendi et Cumming and Poikiloprosopon Sendi et Cumming both in Sendi et al. (2023). The fossil insect expands the temporal and geographic range of its genus and further exemplifies taxonomic and ecological dominance of Umenocoleidae in Burmese amber. The unique wide pronotum without reduced paranotalia (a strong plesiomorphy) also exemplifies disparity of forms among Umenocoleidea.
... Dictyoptera is a medium-sized group of insects with more than 10.000 described extant and fossil species, traditionally comprising cockroaches and termites (order Blattaria s. l.), mantises (order Mantodea) and the extinct family of waterwalking insects (order Chresmoda) (Luo et al. 2022). Cockroaches (Blattaria s. str.) are one of the most dominant insect orders in Paleozoic and Mesozoic ecosystems (Vršanský 2008;Chen et al. 2019;Wappler and Vršanský 2021). ...
... The fossil record of Alienopteridae ranges from Early Cretaceous (Barremian) to Middle Eocene (Ypresian/ Lutetian) with at least 21 species across 16 genera. An undescribed member of this family was also documented from the Cretaceous of Botswana by McKay (2007) (Luo et al. 2022). For a summary of the fossil records of Alienopteridae see Table 1. ...
... This genus is also more robust compared to other genera of the family, with a unique rectangular microstructure on the forewings. The present study follows on the basis of asymmetrical claws known within this genus (and all Alienopteridae but not Umenocoleidae) and lack of clavus (like in Alienopteridae, unlike Umenocoleidae), and also saddleshaped pronotum without paranotalia and without basal delimiting ridge, however, the genus is included in Umenocoleidae by Luo et al. (2022). To further discuss the correct systematic position of Alienopterix is beyond the scope of the present paper. ...
Cockroaches (Blattaria s. str.) were documented from numerous amber localities around the world, representing both extinct and extant families. Alienopteridae is an extinct cockroach family known only from the Cretaceous of Gondwana (Brazil, Botswana, Myanmar amber) and the Cenozoic of North America. Alienopterix santonicus sp. n. from the Late Cretaceous amber of the Ajka Coal Formation (Bakony Mts, western Hungary) extends the rich geographical distribution of the family into Laurasia during the Mesozoic. As a member of the presumably pollinator cohort Alienopteridae, this species could have played an important role in the Ajka Coal ecosystem during the Santonian. The microrectangular structures of the forewing suggest that the new species likely possessed a metallic colouration already known from the group. Combined with the disruptive body pattern this could have served as an advanced camouflage. The microrectangular structures of the forewing were compared to integument microstructures of extant insects with metallic colouration. Various arthropod taxa are already known from ajkaite, and the new discovery further emphasizes the importance of this amber.
... (D) Lacewing larvae with debris-carrying camouflage [96]. (E) Ant-mimicking alienopterid nymph [43]. (F) Camouflaged lacewing larva preying on an alienopterid nymph [43]. ...
... (E) Ant-mimicking alienopterid nymph [43]. (F) Camouflaged lacewing larva preying on an alienopterid nymph [43]. (G) Two hell ants preserved in one amber piece, suggesting a gregarious lifestyle. ...
... Additionally, myrmecophiles are reported in mid-Cretaceous Kachin amber, which is a special social parasitism driven by mature ant eusociality and a reversely definite indicator of ant eusociality [41,42]. Furthermore, ant mimicry had evolved by the mid-Cretaceous in some insects (e.g., alienopterid nymphs) [43], which is contemporary with the earliest ants and their eusociality. In addition to most eusocial stem lineages without modern offspring, all crown ant groups had evolved eusociality [39,40]. ...
The Mesozoic is a key era for the rise of the modern insect fauna. Among the most important evolutionary events in Mesozoic insects are the radiation of holometabolous insects, the origin of eusocial and parasitoid insects, diversification of pollinating insects, and development of advanced mimicry and camouflage. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecospaces. At the same time, insects had evolved more complex and closer ecological associations with various plants and animals. Mesozoic insects played a key and underappreciated ecological role in reconstructing and maintaining terrestrial ecosystems. A greater understanding of the history of insects may help to mitigate future changes in insect diversity and abundance.
... Cockroaches are an extremely diverse order of insects whose fossils date back to the Late Carboniferous (Luo et al. 2022;Schneider and Werneburg 2006;tan 1980;Vršanský et al. 2002;zhang et al. 2012;Liang et al., 2023; see also Wappler and Vršanský;Kazimírová, 2023). Many cockroach fossils are adpressions (e.g. ...
... the present discovery also proves that both currently known genera of the subfamily Vitisminae were distributed across the Laurasian landmass during the Cretaceous (table 1). Interestingly, both Alienopterix and Perspicuus have been reported from the Late Cretaceous (Cenomanian) amber of Myanmar, the so-called burmite (Koubová and Mlynský 2020;Luo et al. 2022;Vršanský et al. , 2021. Further faunistic similarities between the ajkaite and burmite biotas are recognizable: Hersiliidae, Garypinidae, Ceratopogonidae, Phoriidae, Elateridae, Bethylidae and Spathiopterygidae are all known from both ajkaite (Borkent 1997;Hajdu 2015;Szabó et al. 2022a,b,c,d;Novák et al. 2024) and burmite (Cockerell 1920;Engel et al. 2015;Szadziewski et al. 2015;Wunderlich 2015;Grimaldi 2018;zhang et al. 2018;Kundrata et al. 2021). ...
Mesozoic amber cockroaches are rare compared to sedimentary imprints and are only known from Myanmar, Lebanon, France, Russia and USA. Perspicuus csincsii sp. n. from the Late Cretaceous (Santonian) ajkaite amber of Hungary with very long cerci, cup-like terminal palpomere of the maxillary palp and fully carinated legs, is clearly distinguished from all other Vitisminae species by the unique, black forewing with small light-coloured dots/stripes and the absence of pubescence on the wings (autapomorphies). The second cockroach described from the ajkaite adds important data to the distribution pattern of Vitisminae during the Late Cretaceous and further highlights the similarity of the ajkaite and burmite biotas.
... Mesozoic cockroach families with an externally protruding ovipositor are absent in the fossil record after the crisis at the K/Pg boundary, and likely went extinct. An exception is Alienopteridae, whose stratigraphic record extends to the Eocene (Vršanský 2010;Vršanský et al. 2013;Podstrelená and Sendi 2018;Vršanský et al. 2018a, b;Gao et al. 2019;Sendi et al. 2020a;Luo et al. 2022a;Szabó et al. 2022). However, a few Mesozoic lineages without an externally protruding ovipositor (Nocticolidae, Corydiidae, Blattidae, Ectobiidae, Blaberidae), survived the K/Pg crisis and are diverse in living ecosystems (Sendi and Azar 2017;Qiu et al. 2019b; Barna et al. 2019;Sendi et al. 2020b;Šmídová et al. 2021;Vršanský et al. 2022a, b) probably also due to the development of ootheca (Šmídová 2021;Šmídová et al. 2021;Hinkelman 2019). ...
... Species in both families have large globular compound eyes, sclerotized shell-like tegmina, unique leg structures and supracoxal furrow but Umencoleidae differs in having well developed forewings and an adsutural line. Several studies considered Umenocoleidae as basal beetles (Chen and T´an 1973;Nel et al. 2014), or as a stem group of Dermaptera, called Protoelytroptera (Carpenter 1992), but a contemporary consensus is the placement within cockroaches or "Dictyoptera" (Vršanský et al. 2021a, b;Luo et al. 2022a). Lepidopterix has several synapomorphies with the second basalmost (after Perspicuus) genus Jantaropterix, also supported by a morphologically based phylogenetic analysis, which reveals that Jantaropterix and Cratovitisma are rather basal and Compunctiotypus more derived, but with rather low percentual support (Vršanský et al. 2021b;Lee 2016). ...
The earliest amber with numerous important paleobiological samples, and the only significant Lower Cretaceous one containing cockroaches, comes from the Lebanese regions Bouarij, Falougha, Hammana-Mdeirij, Jezzine, Mechmech, Qanat Bakish, Bqaatouta and Rihane (and 21 unstudied outcrops), and from Jordanian amber of Wadi Zerka and Syrian amber of Bloudane. Complex data (RTFI spectroscopy, palynology and entomofauna with diverse and abundant Nematocera) indicated that the amber originated in a subtropical, warm and humid gymnosperm-dominated forest in close proximity to the sea. 79 specimens of cockroaches s. s. (excluding Isoptera, Mantodea and possibly Chresmoda) were housed in 18 species (and three species incertae sedis), including Pravdupovediac neklam, P. maaloufi gen. et spp. n; Elisama globosa, Cratovitisma spinosa and Neoblattella nechapetomu spp. n. The former three belong to the dominant family Blattulidae Vishniakova, 1982 (n = 14), while Umenocoleidae Chen et Tan, 1973 were codominant (n = 10) in the present fossil record. Diversity and disparity of the preserved forms was moderately high and comparable to the Middle Jurassic and Lower Cretaceous sedimentary sites – i.e., higher than in Early Jurassic sites and lower than in Upper Jurassic Karabastau sedimentary rocks and Late Cretaceous North Myanmar amber. Scarce syninclusions in small amber pieces represent a coccid, psychodid, ceratopogonid, possibly a pathogenic fungus and plant trichomes. Palaeogeographically Lepidopterix Sendi, 2020; Cryptoblatta Sendi, 2019; Miniblattina Sendi, 2021; Pravdupovediac gen. n. and possibly Nymphoblatta Vršanský et Grimaldi, 2004 (Lebanese amber); Compunctiotypus Kaddumi, 2005 and Grandocularis Kaddumi, 2005 (Jordanian amber); and Anenev Vršanský, Oružinský, Sendi, Choufani, El-Halabi et Azar, 2019 (Syrian amber) are reported only in the herein studied amber, while the Jantaropterix/ Pseudojantaropterix-complex; Cratovitisma Bechly, 2007; Nymphoblatta Vršanský et Grimaldi, 2004 aff. Perlucipecta Wei et Ren, 2013 and aff. Sivis Vršanský, 2009; Pseudomantina Sendi et Vršanský, 2021; Elisama Giebel, 1856; Ocelloblattula Anisyutkin et Gorokhov, 2008, ?Rhipidoblatta Vishniakova, 1968; Balatronis Šmídová et Lei, 2017 and Neoblatella Shelford, 1911 (nowadays restricted to the Americas) were cosmopolitan with occurrences in both Laurasia and Gondwana. The low percentage (0.4% compared with 2.5–5% in North Myanmar amber) of cockroaches preserved in Lebanese amber could be due to lower viscosity of the amber-forming resin, and/or due to different paleoenvironments, suggested also for Taimyr amber with a moderate climate (constituting 0.3% cockroaches of all samples). Phylogenetically, several still living families, such as Ectobiidae Brunner von Wattenwyl, 1865 and Blattidae Latreille, 1810 have their oldest representatives within Lebanese amber, suggesting that the amber is advanced in evolutionary aspect among all Mesozoic ecosystems (all other families went extinct near Cretaceous–Paleogene boundary, K/Pg). Furthermore, Neoblattella is the earliest recorded still living genus. However, respective species from the present amber complex do not reveal any specific phylogenetical signal and weren’t measurably more basal when compared with their younger North Myanmar amber counterparts. A wide range of morphotypes with various ecological adaptations are documented, suggesting already established, sophisticated trophic relationships, similar as in today’s ecosystems. Nevertheless, given the abundance of blattulids and mesoblattids, most had probably a standard detritivorous feeding habit - the more advanced morphotypes known from Myanmar amber were absent. To summarise, the herein studied amber complex reveals origination of a moderately high diversity and disparity of forms (corresponding to the beginning of the Cretaceous Terrestrial Revolution), similar to Upper Jurassic assemblages, with a number of advanced forms, but lower than in burmite, which might be caused due to collection bias, shorter deposition time, milder tropical climate, or due to a different ecosystem (e.g. with less diversified angiosperms). The present amber reveals the earliest record of already triggered Mesozoic-to-Cenozoic ecosystem change within global forests.
... Myanmar amber (Albian/Cenomanian boundary) contains the most comprehensive fauna (in addition to the extant orders in Figure 3, there are also present the extinct orders Alienoptera, Permopsocida and Tarachoptera; Bai et al. 2016;Huang et al. 2016;Mey et al. 2017), followed by the Levantine belt amber (Hauterivianearly Aptian), Charentes amber (late Albian/early Cenomanian), Spanish Albian amber and New Jersey Turonian amber. The Alienoptera are currently the sister of Mantodea (Luo et al. 2022); the Permopsocida sister to hemipteroids (including lice) and Tarachoptera are caddisfly-like insects (basal to Trichoptera and Lepidoptera); of these, Permopsocida also occurs as rock fossils in the Lower Cretaceous of Russia (Vishniakova 1976). The above occurrences are, however, constrained by the degree of research on different sites; for example, Myanmar currently has the greatest number of described species (Ross 2023). ...
Amber first became relatively abundant and widespread in the geological record during the Cretaceous period. It originated often as copious resin production by a variety of incompletely understood coniferous trees, generally under humid climates, but not excluding seasonal aridity. Study of insect and other organic inclusions only commenced in the twentieth century, but has expanded considerably since then, with several thousand taxa now described. Cretaceous amber insects can be exquisitely preserved in three dimensions, although tend to be biased towards smaller individuals that lived in the local forest environment. They are therefore complemented by the Cretaceous rock record, which sampled larger insects and other habitats. As well as the fine morphological detail exhibited by the amber insect inclusions, various behaviours and interactions unlikely to be otherwise preserved can be found frozen in time, such as brooding behaviour and the entrapment of insects in spiders' webs. Insects in amber also provide important information about evolutionary changes over the course of the Cretaceous, including the rise of eusociality and angiosperm pollination.
Cockroach Clypeblattula panda gen. et sp. n. is described from the Lower Cretaceous Laiyang Formation of Shandong Province, China based on a specimen with forewing and pronotum well-preserved. It is characterized by ovoid pronotum with two trapezoid dark stripes, forewing with intercalary space in R with colouration, A with six simple veins, and sparse cross-veins. It is closely related to the Early Cretaceous Pravdupovediac according to colouration of intercalary space in R, but they can be distinguished mainly based on the different wing shapes and the existence of dark macula. The differences between Clypeblattula gen. n., Ocelloblattula, Pseudomantina, Habroblattula and Laiyangia are also briefly discussed. The new genus is another indigenous cockroach of Blattulidae.
Umenocoleidae is an enigmatic, extinct Mesozoic beetle-like roach family with cosmopolitan distribution erroneously attributed to various insect orders by past authors. Here unusual and well-preserved Archaeospinapteryx tartarensis gen. et sp. n., Trapezionotum vrsanskyi gen. et sp. n., Poikiloprosopon celiae gen. et sp. n., Vzrkadlenie karneri sp. n., and V. saint- germaini sp. n. are described from Cenomanian Burmese amber of the Hukawng Valley. Furthermore, Nigropterix angustata gen. et sp. n. and Umenotypus maculatus gen. et sp. n. are reported from Turonian sediments of Kzyl-Zhar, Kazakhstan. ?Classopolis pollen grains directly attached on the frons of the head of one specimen indiciate pollen transfer, as reported in other representatives of Umenocoleoidea. The herein studied material increases our knowledge of the diversity of this bizarre lineage and extends its temporal and paleogeographic distribution.
Editorial to a special volume of the journal Palaeoentomology, celebrating the life and scientific achievements of Professor Ed Jarzembowski.
Reference: Austen, P.A., Wang, B., Ross, A.J., Coram, R.A. 2022. Edmund Jarzembowski at 70: An appreciation. Palaeoentomology, 5 (3), 195–217.
Protective coloration is observed in numerous extant cockroach species and is prevalent among insects. Such coloration can signal nonprofitability of prey (aposematic) or serve as a camouflage (disruptive). An apparent aposematic isolated macula is identified here among the cockroach Facioblatta perfidia gen. et sp. n. (Liberiblattinidae) from Northern Myanmar amber. In total, 9 and 10 general coloration patterns related to spot-like patterns among extant and fossil species, respectively, are identified. Potential cockroach predators targeted with these patterns varied from dragonflies, small Jurassic pterosaurs and lizards, to Cretaceous and modern frogs, birds and insectivores. Patterns asynchronously appeared throughout the taxonomic spectrum suggesting that the elimination from predators combined with environmental factors influenced the spread of protective coloration among cockroaches.
Despite the abundance of cockroaches (n = 593 specimens of 18 genera and 30 species) in the Mongolian Cretaceous, there is a single formally established and four reported species of Blattaria from the Shar-Tologoy (Valditermes acutipennis Ponomarenko, 1988; Liadoblattina mongolica Vršanský, 2003; Archimesoblatta altera Vršanský, 1997; Praeblattella dichotoma Vršanský, 2003; Cretophotina mongolica Gratshev and Zherikhin, 1993). Nuurcala coloris and Vitisma okata spp. n. are reported here from Early Cretaceous, which represent genera restricted to Laurasia. These fossil genera were documented from Early Cretaceous of Asia (Russian Baissa; Mongolian Bon Tsagaan, Sharin-Gol, Khulirt, Bakhar; Chinese Meitian, Yixian, Daohugou; Japanese Fukui) and Europe (Montsec, Spain). Samples with well-preserved venation and coloration provided correct systematic position with categorization of Shar-Tologoy to northern Laurasian biota (Baissa biota with all Cretaceous Mongolian sites) rather than to southern Jehol biota, and with transitional taxa. This evidences obscured long-lasting (> 50 Ma) isolated occurrences of certain abundant insect groups within narrow areas within Laurasia.
This is a supplement to the Burmese (Myanmar) amber checklist and bibliography covering taxa described or recorded during 2021, plus a few earlier records that were missed previously. Up to the end of 2021, 2,198 species were recorded from Kachin amber of which 337 were named in 2021. Five species were named or recorded from older Hkamti amber.
In spite of big data and new techniques, the phylogeny and timing of cockroaches remain in dispute. Apart from sequencing more species, an alternative way to improve the phylogenetic inference and time estimation is to improve the quality of data, calibrations and analytical procedure. This study emphasizes the completeness of data, the reliability of genes (judged via alignment ambiguity and substitution saturation), and the justification for fossil calibrations. Based on published mitochondrial genomes, the Bayesian phylogeny of cockroaches and termites is recovered as: Corydiinae + (((Cryptocercidae + Isoptera) + ((Anaplectidae + Lamproblattidae) + (Tryonicidae + Blattidae))) + (Pseudophyllodromiinae + (Ectobiinae + (Blattellinae + Blaberidae)))). With two fossil calibrations, namely, Valditermes brenanae and Piniblattella yixianensis , this study dates the crown Dictyoptera to early Jurassic, and crown Blattodea to middle Jurassic. Using the ambiguous ‘roachoid’ fossils to calibrate Dictyoptera+sister pushes these times back to Permian and Triassic. This study also shows that appropriate fossil calibrations are rarer than considered in previous studies.
A new genus and species of the extinct beetle-like dictyopteran family †Umenocoleidae, †Laticephalana liuyani gen. et sp. nov., is described based on a well-preserved adult female from mid-Cretaceous Kachin (Myanmar/Burmese) amber. The new genus is characterized by two conspicuous autapomorphies, a triangular posterior extension of the head capsule and four large protuberances of the pronotum. Both structures can be interpreted as mechanic protective devices, but alternative/additional interpretations are possible. The large female subgenital plate is an autapomorphy of Dictyoptera. The transverse pronotal furrow suggests a placement in a clade with †Alienopteridae and Mantodea. A close relationship between †Laticephalana and †Enervipraela is tentatively supported by a very narrow pronotum and relatively short antennae. The very broad head of †Laticephalana with widely separated large compound eyes indicates predaceous habits, and the slender body and well-developed hindwings good flying abilities. The specializations of the distal legs, very similar to the conditions found in †Alienopteridae, suggest a preference for the foliage of trees and shrubs.
The Umenocoleidae is among the most perplexing fossil insect taxa, widespread at lower and middle latitudes during the Early Cretaceous and probably becoming extinct after the mid-Cretaceous. This problematic taxon was first described from the Lower Cretaceous of China and has been variously assigned to stem-group Coleoptera, Protelytroptera, Blattaria, stem-group Dictyoptera, or Mantodea. The systematic position of the enigmatic family — especially its type species Umenocoleus sinuatus Chen et T’an, 1973 — has remained highly controversial owing to the lack of preserved phylogenetically informative or diagnostic characters. Here, we describe a new specimen of the type species from the type horizon of the type locality (Lower Cretaceous Zhonggou Formation at Jiuquan, Yumen City, China), and additionally two forewings of Ponopterix. We found that the Umenocoleidae is similar to stem-group Coleoptera in its forewing venation but differs in its multi-segmented antennae, orthognathous orientation of the head, subdivision of the pronotum by a transverse furrow, ultrastructure of the forewing punctures, and unfolded hindwings. Our phylogenetic analysis, using an extended matrix of 72 characters and 37 taxa, indicates that the Umenocoleidae is likely a specialized taxon of Dictyoptera, sister to Alienoptera. The beetle-like appearance is interpreted to be a result of convergent evolution.
PREMISE: Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here
we report the frst record of specialized cockroach pollination in the family, involving an
endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were
designed to provide direct proof of cockroach pollination and compare the effectiveness of
other flower visitors.
METHODS: We investigated the reproductive biology, pollination ecology, pollinaria
removal, pollinia insertion, and fruit set following single visits by the most common insects.
In addition, we reviewed reports of cockroaches as pollinators of other plants and analyzed
the known pollination systems in Vincetoxicum in a phylogenetic context.
RESULTS: The small, pale green flowers of V. hainanense opened during the night. The
flowers were not autogamous, but were self-compatible. Flower visitors included beetles,
flies, ants and bush crickets, but the most effective pollinator was the cockroach Blattella
bisignata, the only visitor that carried pollen between plants. Less frequent and effective
pollinators are ants and Carabidae. Plants in this genus are predominantly pollinated by
flies, moths and wasps.
CONCLUSIONS: Globally, only 11 plant species are known to be cockroach-pollinated.
Because their range of floral features encompass similarities and differences, defning a
“cockroach pollination syndrome” is difcult. One commonality is that flowers are often
visited by insects other than cockroaches, such as beetles, that vary in their signifcance
as pollinators. Cockroach pollination is undoubtedly more widespread than previously
thought and requires further attention.
KEY WORDS Apocynaceae; Asclepiadoideae; breeding system; cockroach pollination;
floral biology; pollination system; pollinaria removal; pollinia insertion; reproductive
biology; Vincetoxicum hainanense.
Following a mailbox of comments concerning a letter sent by the Society of Vertebrate Paleontology to journal editors on “Fossils from conflict zones...” dated 21 April 2020 calling for a ban on publications on Burmese amber, it was felt necessary to air some concerns raised for further discussion.
For more than a century there has been a fascination with the surprisingly rapid rise and early diversity of flowering plants (angiosperms). Darwin described the seemingly explosive diversification of angiosperms as an “abominable mystery,” and debates continue about the origin and processes driving angiosperm speciation. Dating the origin of angiosperms was traditionally the prerogative of paleobotanists who read the fossil record of plants, but with DNA sequencing becoming increasingly sophisticated, molecular dating methods have come to the table. Many angiosperm fossils can be dated to the Early Cretaceous (∼135 million years ago), which has led paleobotanists to reason that they originated during that era. It is now increasingly recognized that angiosperms are probably older than the oldest fossils, but how much older remains controversial. When angiosperms originated is key to understanding the origin and evolution of pollinators, particularly insects such as bees, butterflies, moths, and flies.
The Cretaceous fossil record of amber provides a variety of evidence that is essential for greater understanding of early pollination strategies. Here, we describe four pieces of ca. 99-million-year-old (early Cenomanian) Myanmar amber from Kachin containing four closely related genera of short-winged flower beetles (Coleoptera: Kateretidae) associated with abundant pollen grains identified as three distinct palynomorphotypes of the gymnosperm Cycadopites and Praenymphaeapollenites cenomaniensis gen. and sp. nov., a form-taxon of pollen from a basal angiosperm lineage of water lilies (Nymphaeales: Nymphaeaceae). We demonstrate how a gymnosperm to angiosperm plant-host shift occurred during the mid-Cretaceous, from a generalist pollen-feeding family of beetles, which served as a driving mechanism for the subsequent success of flowering plants.
Insect pollination of flowering plants (angiosperms) is responsible for the majority of the world’s flowering plant diversity and is key to the Cretaceous radiation of angiosperms. Although both insects and angiosperms were common by the mid-Cretaceous, direct fossil evidence of insect pollination is lacking. Direct evidence of Cretaceous insect pollination is associated with insect-gymnosperm pollination. Here, we report a specialized beetle-angiosperm pollination mode from mid-Cretaceous Burmese amber (99 mega-annum [Ma]) in which a tumbling flower beetle (Mordellidae), Angimordella burmitina gen. et sp. nov., has many tricolpate pollen grains attached. A. burmitina exhibits several specialized body structures for flower-visiting behavior including its body shape and pollen - feeding mouthparts revealed by X-ray microcomputed tomography (micro-CT). The tricolpate pollen in the amber belongs to the eudicots that comprise the majority of extant angiosperm species. These pollen grains exhibit zoophilous pollination attributes including their ornamentation, size, and clumping characteristics. Tricolpate pollen grains attached to the beetle’s hairs are revealed by confocal laser scanning microscopy, which is a powerful tool for investigating pollen in amber. Our findings provide direct evidence of insect pollination of Cretaceous angiosperms, extending the range insect-angiosperm pollination association by at least 50 million years. Our results support the hypothesis that specialized insect pollination modes were present in eudicots 99 million years ago.
Convergence between the Indian and Asian plates has reshaped large parts of Asia, changing regional climate and biodiversity, yet geodynamic models fundamentally diverge on how convergence was accommodated since the India–Asia collision. Here we report palaeomagnetic data from the Burma Terrane, which is at the eastern edge of the collision zone and is famous for its Cretaceous amber biota, to better determine the evolution of the India–Asia collision. The Burma Terrane was part of a Trans-Tethyan island arc and stood at a near-equatorial southern latitude at ~95 Ma, suggesting island endemism for the Burmese amber biota. The Burma Terrane underwent significant clockwise rotation between ~80 and 50 Ma, causing its subduction margin to become hyper-oblique. Subsequently, it was translated northward on the Indian Plate by an exceptional distance of at least 2,000 km along a dextral strike-slip fault system in the east. Our reconstructions are only compatible with geodynamic models involving an initial collision of India with a near-equatorial Trans-Tethyan subduction system at ~60 Ma, followed by a later collision with the Asian margin.
Significance
Aquatic organisms are rarely found in amber, but when they occur they provide invaluable evidence for the better understanding of amber taphonomy and past ecosystems. We report an ammonite and several marine gastropods alongside a mixed assemblage of intertidal and terrestrial forest floor organisms in mid-Cretaceous Burmese amber. Our discovery indicates that the Burmese amber forest was living near a dynamic and shifting coastal environment. The ammonite also provides supporting evidence for the age of the amber, which is still debated, and represents a rare example of dating using fossils present inside the amber.
Complex interspecies relationships are widespread among metazoans, but the evolutionary history of these lifestyles is poorly understood. We describe a fossil beetle in 99-million-year-old Burmese amber that we infer to have been a social impostor of the earliest-known ant colonies. Promyrmister kistneri gen. et sp. nov. belongs to the haeteriine clown beetles (Coleoptera: Histeridae), a major clade of ‘myrmecophiles’—specialized nest intruders with dramatic anatomical, chemical and behavioral adaptations for colony infiltration. Promyrmister reveals that myrmecophiles evolved close to the emergence of ant eusociality, in colonies of stem-group ants that predominate Burmese amber, or with cryptic crown-group ants that remain largely unknown at this time. The clown beetle-ant relationship has been maintained ever since by the beetles host-switching to numerous modern ant genera, ultimately diversifying into one of the largest radiations of symbiotic animals. We infer that obligate behavioral symbioses can evolve relatively rapidly, and be sustained over deep time.
Long-proboscid scorpionflies are enigmatic, mid-Mesozoic insects associated with gymnosperm pollination. One major lineage, Aneuretopsychina, consists of four families plus two haustellate clades, Diptera and Siphonaptera. One clade, Pseudopolycentropodidae, from mid-Cretaceous Myanmar amber, contains Parapolycentropus. Here, we newly establish Dualula, assigned to Dualulidae, constituting the fifth lineage. Parapolycentropus and Dualula lineages are small, two-winged, with unique siphonate mouthparts for imbibing pollination drops. A cibarial pump provides siphonal food inflow; in Dualula, the siphon base surrounds a hypopharynx housing a small, valved pump constricted to a narrow salivary duct supplying outgoing enzymes for food fluidization. Indirect evidence links long-proboscid mouthpart structure with contemporaneous tubulate ovulate organs. Direct evidence of gymnospermous Cycadopites pollen is associated with one Parapolycentropus specimen. Parapolycentropus and Dualula exhibit hind-wing reduction that would precede haltere formation, likely caused by Ultrabithorax. Distinctive, male Aneuretopsychina genitalia are evident from specimens in copulo, supplemented by mixed-sex individuals of likely male mating swarms.
Niche diversity of pollinating insects plays a vital role in maintaining extant terrestrial ecosystems. A key dimension of pollination niches refers to the insect proboscis length that commonly matches the floral tube length. Here we describe new kalligrammatid lacewings (an iconic Mesozoic pollinating insect lineage) from late Cretaceous Burmese amber and Mesozoic sediments in China. Kalligrammatids display complex configurations of elongate mouthpart elements consisting of well-developed maxillae, labium and their palps. The mouthpart lengths vary among species, from 0.6 to 18.0 mm, suggesting corresponding variability in the floral tube lengths of Mesozoic plants. With the diversification of pollinating habits, the kalligrammatids presented highly divergent traits related to chemical communication and defence mechanisms. Together with other Mesozoic long-proboscid insects, these fossils not only reveal the high niche diversity of Mesozoic pollinating insects but also highlight the diversity of Mesozoic pollinator-dependent plants prior to the rise of angiosperms.
Alienoptera is an insect order recently described from mid-Cretaceous amber and is phylogenetically nested in the Dictyoptera lineage. Alienoptera currently comprises three species: Alienopterus brachyelytrus, Alienopterella stigmatica and Caputoraptor elegans. The most interesting is Caputoraptor elegans, which was recently described in Current Biology by Bai and colleagues and which has an unusual cephalo-thoracic
device formed by wing-like extensions of the genae and the corresponding edges of the pronotum. Bai and colleagues suggested that the cephalo-thoracic apparatus may have
been used to hold the female and male together during copulation. According to this possible function, the cephalothoracic apparatus of the female would fi t together with the spread forewings of the male while the female was on the back of the male during
copulation. This function was proposed based on examination of females and nymphs, and the authors stated that it could be falsifi ed if a male with a similar apparatus were discovered. After examining a male nymph of this species, I here suggest that
the cephalo-thoracic apparatus was not used for copulation but was instead used for predation and feeding.
Batesian mimicry is a relationship in which a harmful organism (the model) is mimicked by a harmless organism (the mimic), which gains protection because predators mistake it for the model. It is the most widely studied of mimicry complexes and has undoubtedly played an important role in the speciation of various animals especially insects. However, little is known about the early evolution of this important behavior and its evolutionary significance owing to a dearth of paleontological records. Here we report several specialized representatives of the family Alienopteridae from the Early Cretaceous of Brazil, mid-Cretaceous Burmite, and the Eocene of the USA. They exhibit unique morphological adaptations for wasp and ant mimicry and represent one of the oldest evidence of Batesian mimicry in the insect fossil record. Our findings reveal at least 65-million-year coevolution between extinct alienopterids and aculeates. Phylogenetic Bayesian network analysis houses Alienopteridae within Umenocoleidae explosively radiating ~127 Ma. Alienopteridae is the only Mesozoic-type cockroach family which passed K/Pg.
Dictyoptera, which comprises cockroaches, termites and mantids, is a quite successful group of insects in evolutionary terms with a long fossil record—roachoid insects were already abundant 315 million years ago in the Carboniferous forests. One of the most remarkable autapomorphies of extant dictyopterans, and possibly a major factor for their persisting success, is the ability to produce oothecae. Despite the robustness of this sort of egg package, fossils of oothecae are very rare, the oldest direct evidences being from the Cretaceous Crato Formation in Brazil (115 mya). The ability to produce oothecae is presumably linked to a specific ovipositor morphology, including a significant length reduction. Hence, ovipositor morphology can indirectly inform about the reproductive strategy of a species. Herein we describe the ovipositor morphology of various fossil forms of dictyopteran insects. Early fossil roachoids, in contrast to the modern forms, possessed a very long and prominent ovipositor, reminiscent of the ovipositor in orthopterans (Ensifera), indicating that these forms laid individual, rather small eggs into a substrate. We present examples from different fossil deposits, which show the entire range of ovipositor morphologies, from very long forms over forms with ovipositors partly reduced in length to modern-appearing morphologies. Most remarkably, different shapes of ovipositors seem to be present in roachoids in the fauna of the 115 million years old Crato Formation—species with long prominent ovipositors co-existed with species with a reduced short and broad ovipositor. Additionally, females that carry oothecae attached to their abdomen indicate a third type of ovipositor: a further reduced ovipositor as seen in modern forms, which already allowed the internal production of oothecae.
Alienoptera have been recently described from mid-Cretaceous amber and are nested phylogenetically inside the Dictyoptera lineage as the sister group of Mantodea. The second known species, Alienopterella stigmatica gen. et sp. nov., is described and illustrated in this contribution based on a male embedded in Cretaceous Burmese amber of earliest Cenomanian age. The well-preserved holotype allows clarification of the characteristics of the order. The first-studied hind wings are derived from the Dictyoptera ground plan. The membrane is transparent, veins are thickened and strongly sclerotized, and between C and SC2 is a conspicuous leathery lancet-shaped pterostigma. The wings are folded longitudinally back on the abdomen between the CuP and AA1 veins in repose. The palaeobiology of Alienoptera is discussed based on the morphology of both known species. Alienopterans are inferred to have lived in trees or bushes with suitable foliage and were probably daytime active, visually oriented predators of small invertebrates.
During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2].Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance. However, most evidence supports gymnosperm–insect pollinator associations, buttressed by direct evidence of pollen on insect bodies, currently established for four groups: Thysanoptera (thrips), Neuroptera (lacewings), Diptera (flies), and now Coleoptera (beetles). Each group represents a distinctive pollination mode linked to a unique mouthpart type and feeding guild [4–9]. Extensive indirect evidence, based on specialized head and mouthpart morphology, is present for one of these pollinator types, the long-proboscid pollination mode [10], representing minimally ten family-level lineages of Neuroptera, Mecoptera (scorpionflies), and Diptera [8, 10, 11]. A recurring feature uniting these pollinator modes is host associations with ginkgoalean, cycad, conifer, and bennettitalean gymnosperms. Pollinator lineages bearing these pollination modes were categorized into four evolutionary cohorts during the 35-million year-long angiosperm radiation, each defined by its host-plant associations (gymnosperm or angiosperm) and evolutionary pattern (extinction, continuation, or origination) during this interval [12]. Here, we provide the first direct evidence for one cohort, exemplified by the beetle Darwinylus marcosi, family Oedemeridae (false blíster beetles), that had an earlier gymnosperm (most likely cycad) host association, later transitioning onto angiosperms [13]. This association constitutes one of four patterns explaining the plateau of family-level plant lineages generally and pollinating insects specifically during the mid-Cretaceous angiosperm radiation [12].
A comprehensive revision of 981 specimens of fossil cockroaches from the Lower Cretaceous laminated limestones of the Crato Formation of Northeast Brazil shows that they belong to eleven taxa, including Piniblattella limai, P. magna sp. n., Perlucipecta santanensis. sp. n., Raptoblatta waddingtonae; Ocelloblattula santanensis sp. n., Elisama brevis (= E. americana, syn.n.), E. hindwingnii sp. n., Ponopterix axelrodi (= P. maxima syn.n.), Umenopterix burkhardi comb. n., and Cratovitisma oldreadi (Umenocoleidae = Cratovitismidae syn.n. = Ponopterixidae syn.n.). The family Ectobiidae is numerically most abundant in the assemblage of cockroaches of the Crato Formation (83 % of cockroaches), followed by Blattulidae (13 %) and Umenocoleidae (4 %). 79.2 % of specimens are complete and fully articulated. Members of the family Alienopteridae are probably also present. Representatives of a relatively common Mesozoic superfamily Caloblattinoidea are missing. With the exception of the endemic genera Cratovitisma and Raptoblatta and the exclusively Gondwanan genus Ocelloblattula, all other genera were cosmopolitan. Taxonomic richness of cockroaches of the Crato Formation is thus rather low, and consists of geologically long-ranging and geographically-widespread genera, genera restricted to Gondwana, and short-ranging endemic genera found in the Crato Formation only.
Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore , little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.
A new insect species (†Alienopterus brachyelytrus Bai, Beutel, Klass, Wipfler et Zhang gen. et sp. nov.) of a new order and family is described, based on a single male embedded in Cretaceous Burmese amber (ca. 99 Ma). Unusual characters are shortened forewings combined with fully developed, operational hindwings, similar as in Dermaptera, and specialized attachment pads otherwise only found in mantophasmatodeans (heelwalkers). A cladistic analysis suggests a placement as sister to Mantodea, supported by a profemoral brush and other characters. The male genitalia show the same pattern in both groups. Specialized features are the unusual flight apparatus, attachment structures adapted for locomotion on leaves, and a dense profemoral setation suitable for catching small prey. †Alienopterus was apparently able to fly and likely a predator of small arthropods in bushes or trees. An impressive radiation of Mantodea started in similar habitats at least 35 Ma later in the early Cenozoic. In contrast, †Alienopterus was an evolutionary dead end in the roach-mantis transition zone.
Mid-Mesozoic kalligrammatid lacewings (Neuroptera) entered the fossil record 165 million years ago (Ma) and disappeared 45 Ma later. Extant papilionoid butterflies (Lepidoptera) probably originated 80–70 Ma, long after kalligrammatids became extinct. Although poor preservation of kalligrammatid fossils previously prevented their detailed morphological and ecological characterization, we examine new, well-preserved, kalligrammatid fossils from Middle Jurassic and Early Cretaceous sites in northeastern China to unravel a surprising array of similar morphological and ecological features in these two, unrelated clades. We used polarized light and epifluorescence photography, SEM imaging, energy dispersive spectrometry and time-of-flight secondary ion mass spectrometry to examine kalligrammatid fossils and their environment. We mapped the evolution of specific traits onto a kalligrammatid phylogeny and discovered that these extinct lacewings convergently evolved wing eyespots that possibly contained melanin, and wing scales, elongate tubular proboscides, similar feeding styles, and seed–plant associations, similar to butterflies. Long-proboscid kalligrammatid lacewings lived in ecosystems with gymnosperm–insect relationships and likely accessed bennettitalean pollination drops and pollen. This system later was replaced by mid-Cretaceous angiosperms and their insect pollinators.
Alienopterixinae subfam. n. (with Alienopterix Mlynský et al. in Vršanský et al. (2018), Nadveruzenie gen. n., Vzrkadlenie Vršanský in Sendi et al. (2020) and Enervipraeala Luo, Xu et Jarzembowski, 2020) is proposed to house alienopterids with fully developed tegmina (symplesiomorphy with all Umenocoleidae) and a compact uniform pronotum (plesiomorphy). At least seven distinct morphological species in this complex are preserved in burmite. Alienopterix smidovae Hinkelman, sp. n./ Alienopterix mlynskyi Sendi, sp. n. possess autapomorphies, such as the absence of coloration and bunky organised in transverse rows, complex pronotum and red eye coloration respectively. Both species exhibit grooved forewing structure similar to unrelated Melyroidea Shelford, 1912 with metallic coloration. A male (unformalised) with short, symmetrical and multisegmented styli is identified for the first time. Bootstrap analysis of Umenocoleoidea now further diminishes differences between Umenocoleidae and Alienopteridae, revealia lack of structure and hierarchy in combined morphological data, while retaining structure when restricted to species from one locality. Nadveruzenie postava Vrsansky, Hinkelman et Sendi, gen. et sp. n. is described, autapomorphies include extremely thin cerci, fenestrate structure of forewings with structured fore margin and absent clavus, similar to living genus Aclavoidea Vidlička et Vršanský in Hinkelman et al. (2020). Diversity index within Umenocoleoidea (disregarding dominant Jantaropterix and Perspicuus pilosus Koubová in Koubová and Mlynský (2020) in burmite is near 1.0. Blattocoprolites alienopterixmlynskyi and Blattocoprolites jantaropterixellenbergeri Hinkelman, ichnospp. n., preserved and partially protruding coprolites, document defecation during burial.
This is a supplement to the Burmese (Myanmar) amber checklist and bibliography covering taxa described or recorded during 2020, plus a few earlier records that were missed previously. Up to the end of 2020, 1,859 species were recorded from Kachin amber of which 362 were named in 2020, which is the highest number of species named from any kind of amber in one year. Two species were also named from older Hkamti amber.
A new genus and species of the enigmatic beetle-like family Umenocoleidae, Enervipraeala nigra gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Kachin (Myanmar) amber. The new genus mainly differs from the other genera in the ratio of the width of the head and pronotum, the square-shaped pronotum, the subrectangular dark pattern of the forewing, and few branches of radial veins on the hindwing. The internal taxonomy of Umenocoleidae is briefly discussed. Vitisma Vrsanský, 1999 and Permoponopterix Nel, Prokop et Kirejtshuk, 2014 are excluded from Umenocoleoidea, and Antophiloblatta Sendi, 2020, Jantaropterix Vrsanský et Grimaldi, 2003, Lepidopterix Sendi, 2020 and Perspicuus Koubova, 2020 are transferred from Umenocoleidae to Cratovitismidae. Alienopterix Mlynský, Vrsanský et Wang, 2018 and Vzrkadlenie Vrsanský, 2020 are transferred from Alienopteridae to Cratovitismidae.
Extinct haidomyrmecine ‘‘hell ants’’ are among the earliest ants known. These eusocial Cretaceous taxa diverged from extant lineages prior to the most recent common ancestor of all living ants and possessed bizarre scythe-like mouthparts along with a striking array of horn-like cephalic projections. Despite the morphological breadth of the fifteen thousand known extant ant species, phenotypic syndromes found in the Cretaceous are without parallel and the evolutionary drivers of extinct diversity are unknown. Here, we provide a mechanistic explanation for aberrant hell ant morphology through phylogenetic reconstruction and comparative methods, as well as a newly reported specimen. We report a remarkable instance of fossilized predation that provides direct evidence for the function of dorsoventrally expanded mandibles and elaborate horns. Our findings confirm the hypothesis that hell ants captured other arthropods between mandible and horn in a manner that could only be achieved by articulating their mouthparts in an axial plane perpendicular to that of modern ants. We demonstrate that the head capsule and mandibles of haidomyrmecines are uniquely integrated as a consequence of this predatory mode and covary across species while finding no evidence of such modular integration in extant ant groups. We suggest that hell ant cephalic integration— analogous to the vertebrate skull—triggered a pathway for an ancient adaptive radiation and expansion into morphospace unoccupied by any living taxon.
Ant mimicry, i.e., the mimicking of ant workers by another organism, is a widespread phenomenon among different groups of Euarthropoda, including spiders and different insect species. One example of ant mimicry occurs among praying mantises (Mantodea); here the first stage nymphs have been recorded to perform ant mimicry. In this study, we investigated different nymphal instars of Miomantis binotata for possible morphological similarities to ants. The different instars were compared as stages supposed to perform ant mimicry would differ morphologically from those stages not supposed to resemble ants. The specimens were investigated under different microscopic settings and measurements were performed. Our results do not show significant differences concerning morphological measurements or shape of structures between the different nymphal instars of M. binotata. One prominent difference between stage one nymphs and later stages occurs in the colouration of the body, which is very dark in the earliest nymph. This difference might explain why young nymphs of Miomantis binotata are interpreted as ant-mimicking, despite the apparent lack of other morphological resemblances.
Variations of speciation and extinction rates determine the fate of clades through time. Periods of high diversification and extinction (possibly mass‐extinction events) can punctuate the evolutionary history of various clades, but they remain loosely defined for many biological groups, especially nonmarine invertebrates like insects. Here, we examine whether the cockroaches, mantises and termites (altogether included in Dictyoptera) have experienced episodic pulses of speciation or extinction and how these pulses may be associated with environmental fluctuations or mass extinctions. We relied on molecular phylogeny and fossil data to shed light on the times and rates at which dictyopterans diversified. The diversification of Dictyoptera has alternated between (i) periods of high diversification in the late Carboniferous, Early–Middle Triassic, Early Cretaceous and middle Palaeogene, and (ii) periods of high extinction rates particularly at the Permian‐Triassic boundary, but not necessarily correlated with the major global biodiversity crises as in the mid‐Cretaceous. This study advocates the importance of analyzing, when possible, both molecular phylogeny and fossil data to unveil diversification and extinction periods for a given group. The causes and consequences of extinction must be studied beyond mass‐extinction events alone to gain a broader understanding of how clades wax and wane.
This is a supplement to Ross (2019) covering all taxa described or recorded in Burmese amber during 2019, plus a few earlier records that were missed previously. Up to the end of 2019, 1,478 species were recorded from Burmese (Kachin) amber of which 276 were named or recorded in 2019.
The systematic position of the Cretaceous genus †Umenocoleus
Chen & Tan is re-evaluated. The re-assignment in
2014 back to Coleoptera is rejected based on numerous
morphological features incompatible with such a placement.
This includes an orthognathous head, multi-segmented
antennae, the lack of a cephalic neck region, the
exposed cervical membrane, a dorsal surface with cupshaped
punctures but without tubercles, moderately sclerotized
forewings with rounded apices and lacking window
punctures, the lack of an elevated mesoscutellar shield, and
unfolded hind wings with numerous veins. Supposedly ancestral
coleopteran features are implausible considering the
comparatively young age (Early Cretaceous). As previously
suggested, the genus is phylogenetically closely related
to “roachoids” like †Ponopterix Vršanský & Grimaldi and
†Petropterix Vršanský (†Umenocoleoidea Chen & Tan;
see Vršanský, 2003) and probably also to †Alienopteridae
(†Alienoptera).
Direct fossil evidence for Mesozoic flower pollination is scarce. Umenocoleoid micro-cockroaches Lepidopterix vegrandis gen. et sp. n. (Lebanese amber) and Antophiloblatta hispida gen. et sp. n. (Myanmar amber) possess size, form, complex coloration pattern and surface structure, cryptic with potentially entomophilous angiosperms Tropidogyne pentaptera Poinar, 2017 and Antiquifloris latifibris Poinar et Buckley, 2016 flower petals and sepals. Putative pollen grains attached to the latter adult indicates pollination, while reduced mouthparts suggest fluid nectar feeding. Spongistoma angusta gen. et sp. n. (Myanmar amber) has a narrow body and mandibles nearly entirely reduced with a unique “proboscis” forming sponging/ sucking mouthparts. In addition putative Classopolis Pflug, 1953 gymnosperm pollen is attached to adults and immature individuals of Vzrkadlenie miso gen. et sp. n. (Myanmar amber). Together with possible angiosperm pollination by Formicamendax vrsanskyi Hinkelman, 2019 and cycas pollination by immature individuals of alienopterid larvae, the evidence for early cockroach pollination is now substantial. Additionally unique is the forewing surface of L. vegrandis with photonic crystal structures within the scales.
Structural features and life habits of described species of the extinct †Alienoptera are evaluated based on previously published studies on the group. Head structures and feedings habits are addressed, as are the locomotor organs, especially the wings and adhesive devices. Suggested pollen feeding habits and the possible role as pollinators are discussed, as well as hypothesized ant and wasp mimicry and myrmecophily. Species of †Alienoptera were likely predators, in the case of †Caputoraptor elegans Bai, Beutel et Wipfler, 2018 with a unique cephalo-prothoracic prey grasping mechanism. They were likely strong fliers with anatomical dipterism with functional hind wings. Wing joints protected by scale-like sclerotized fore wings probably allowed them to move very efficiently in dense foliage of trees or shrubs and to prey upon smaller insects. Ant mimicry, myrmecophily and “weevil mimicry” are rejected. †Meilia Vršanský et Wang, 2018 is a possible case of wasp mimicry but more evidence is required. Other suggested cases of mimicking wasps are unfounded.
Morphological insect-insect mimicry is known from few Cretaceous cockroaches and a beetle. Formicamendax vrsanskyi gen. et sp. n. (Blattaria, Alienopteridae) shows myrmecomorph features such as an elongated, smooth and black body, simple fenestrated hindwing, legs lacking protective spines. Elbowed or “geniculate “antenna is a typical character of advanced ants and weevils used for different forms of communication. Together with reduced mouthparts and specialized palps still preserved grasping food, they evidence specialized behavioral mimicry. The attached symmetric angiosperm pollen on hindleg can provide rare evidence of insect-flower relations.
Polyneoptera represents one of the major lineages of winged insects, comprising around 40,000 extant species in 10 traditional orders, including grasshoppers, roaches, and stoneflies. Many important aspects of polyneopteran evolution, such as their phylo-genetic relationships, changes in their external appearance, their habitat preferences, and social behavior, are unresolved and are a major enigma in entomology. These ambiguities also have direct consequences for our understanding of the evolution of winged insects in general; for example, with respect to the ancestral habitats of adults and juveniles. We addressed these issues with a large-scale phylogenomic analysis and used the reconstructed phylogenetic relationships to trace the evolution of 112 characters associated with the external appearance and the lifestyle of winged insects. Our inferences suggest that the last common ancestors of Polyneoptera and of the winged insects were terrestrial throughout their lives, implying that wings did not evolve in an aquatic environment. The appearance of the first polyneopteran insect was mainly characterized by ancestral traits such as long segmented abdominal appendages and biting mouthparts held below the head capsule. This ancestor lived in association with the ground, which led to various specializations including hardened forewings and unique tarsal attachment structures. However, within Polyneoptera, several groups switched separately to a life on plants. In contrast to a previous hypothesis, we found that social behavior was not part of the polyneopteran ground plan. In other traits, such as the biting mouthparts, Polyneoptera shows a high degree of evolutionary conservatism unique among the major lineages of winged insects. lower winged insects | Polyneoptera | Pterygota | Neoptera | phylogenomics
Myrmecophilous and termitophilous interactions likely contributed to the competitive advantage and evolutionary success of eusocial insects, but how these commensal and parasitic relationships originated is unclear due to absence of fossil records. New extinct cockroaches of the still living family Blattidae are reported here from the Cretaceous Myanmar amber (99 Ma) and are the earliest known inhabitants of complex ant nests, demonstrating that this specialised myrmecophily originated shortly after ant eusociality and appeared in the fossil record. Cretaceous stem aposematic Blattidae are known from the amber of Myanmar and Lebanon and we report them here also from the Syrian amber. Concurrent evolution suggests that the collective internal defence of early ants was weak and allowed infiltrations by numerous unrelated organisms, At the same time, the contemporary presence of ant mimicking myrmecomorphs suggests a need for strong external protection against visually hunting predators. Myrmecophily is supported by morphological adaptations (lack of wide fat body and feeding of adult male; short, fossorial legs; shortened cerci; oligomerised antenna; hairy surface structures) and camouflage behaviour, documented by sediment and own feces covering. Moreover the same piece of amber contains ants, ant mimics and other undescribed ant nest-visiting insects as syninclusions. Another species preserved along with two termites is a putative termitophile. Abundant comparatively large parasitic cockroaches influenced Mesozoic tropical forest ecosystems by affecting the early evolution of complex nests of eusocial insects. Rainforest rudiments in South Yunnan yielded observation of analogical still living, formally undescribed species.
Cycads, unlike modern wind-pollinated conifers and Ginkgo, are unusual in that they are an ancient group of gymnosperms pollinated by insects [1, 2, 3]. Although it is well documented that cycads were diverse and abundant during the mid-Mesozoic, little is known about their biogeography and pollination before the rise of angiosperms. Direct fossil evidence illuminating the evolutionary history of cycads is extremely rare [4, 5]. Here we report a specialized beetle-mediated pollination mode from the mid-Cretaceous of Myanmar, wherein a new boganiid beetle, Cretoparacucujus cycadophilus, with specialized pollen-feeding adaptations in its mouthparts and legs, was associated with many pollen grains of Cycadopites. Phylogenetic analyses indicate Cretoparacucujus as a sister group to the extant Australian Paracucujus, which pollinate the cycad Macrozamia riedlei. Our discovery, along with the current disjunct distribution of related beetle-herbivore (tribe Paracucujini) and cycad-host (tribe Encephalarteae) pairs in South Africa and Australia, indicate a probable ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before angiosperm dominance and the radiation of flowering-plant pollinators later in the Cretaceous.
Cratovitisma odlreadi Bechly, 2007 – a beetle-like cockroach, known from single Lower Cretaceous sediment specimen from Crato in Brazil, was designated by monotypy. C. cortexi Sendi, sp.n. (Lebanon) and C. bechlyi Podstrelená, sp.n. (Myanmar) from Early and Late Cretaceous amber respectively reflect a specific bark niche with unique disruptive camouflage coloration and minimum morphological differences over the significant temporal (130–120–98 Ma) and spatial (Laurasia – Gondwana) gaps. The earliest derivation within the family is documented with significantly symplesiomorphic (with Jantaropterix Vršanský, 2003) fully carinated legs. © 2018, E. Schweizerbart'sche Verlagsbuchhandlung. All rights reserved.
Insects use different parts of their body to hold on to mating partners, catch prey or to defend themselves, in most cases the mouthparts or the legs. However, in 400 million years of evolution1,2, specialized devices were independently acquired in several groups to adopt these tasks, as for instance modified legs in mantids, assassin bugs or stick insects3-5, or clasping antennae of the globular springtails6. So far no known species used its neck region between the head and thorax in this context. Here we describe females of †Caputoraptor elegans, a very unusual, presumably predacious insect discovered in approximately 100 million years old7 Burmese amber. Based on several morphological features, we conclude that this species lived in the foliage of trees or bushes. A unique feature of the new taxon is a scissor-like mechanism formed by wing-like extensions on the posterior head and corresponding serrated edges of the dorsal sclerite of the first thoracic segment. Based on the specific structure of the apparatus, we conclude that it most likely was used by females to hold on to males during copulation. A defensive or prey-catching purpose appear less likely. A similar mechanism did not evolve in any other known known group of extant or extinct insects.
Amino acid sequence data are available for ribulose biphosphate carboxylase, plastocyanin, cytochrome c, and ferredoxin for a number of angiosperm families. Cladistic analysis of the data, including evaluation of all equally or almost equally parsimonious cladograms, shows that much homoplasy (parallelisms and reversals) is present and that few or no well supported monophyletic groups of families can be demonstrated. In one analysis of nine angiosperm families and 40 variable amino acid positions from three proteins, the most parsimonious cladograms were 151 steps long and contained 63 parallelisms and reversals (consistency index = 0.583). In another analysis of six families and 53 variable amino acid positions from four proteins, the most parsimonious cladogram was 161 steps long and contained 50 parallelisms and reversals (consistency index = 0.689). Single changes in both data matrices could yield most parsimonious cladograms with quite different topologies and without common monophyletic groups. Presently, amino acid sequence data are not comprehensive enough for phylogenetic reconstruction among angiosperms. More informative positions are needed, either from sequencing longer parts of the proteins or from sequencing more proteins from the same taxa.
This beautifully illustrated 2007 volume describes the entire flora and fauna of the famous Lower Cretaceous Crato Formation of Brazil - one of the world's most important fossil deposits, exhibiting exceptional preservation. A wide range of invertebrates and vertebrates are covered, including extended sections on pterosaurs and insects. Two chapters are devoted to plants. Many of the chapters include descriptions of new species and re-descriptions and appraisals of taxa published in obscure places, rendering them available to a wider audience. Fossil descriptions are supported by detailed explanations of the geological history of the deposit and its tectonic setting. Drawing on expertise from around the world and specimens from the most important museum collections, this book forms an essential reference for researchers and enthusiasts with an interest in Mesozoic fossils.
Across terrestrial ecosystems, modern ants are ubiquitous. As many as 94 out of every 100 individual arthropods in rainforests are ants [1], and they constitute up to 15% of animal biomass in the Amazon [2, 3]. Moreover, ants are pervasive agents of natural selection as over 10,000 arthropod species are specialized inquilines or myrmecomorphs living among ants or defending themselves through mimicry [4, 5]. Such impact is traditionally explained by sociality: ants are the first major group of ground-dwelling predatory insects to become eusocial [3], increasing efficiency of tasks and establishing competitive superiority over solitary species [6, 7]. A wealth of specimens from rich deposits of 99 million-year-old Burmese amber resolves ambiguity regarding sociality and diversity in the earliest ants. The stem-group genus Gerontoformica maintained distinct reproductive castes including morphotypes unknown in solitary aculeate (stinging) wasps, providing insight into early behavior. We present rare aggregations of workers, indicating group recruitment as well as an instance of interspecific combat; such aggression is a social feature of modern ants. Two species and an unusual new genus are described, further expanding the remarkable diversity of early ants. Stem-group ants are recovered as a paraphyletic assemblage at the base of modern lineages varying greatly in size, form, and mouthpart structure, interpreted here as an adaptive radiation. Though Cretaceous stem-group ants were eusocial and adaptively diverse, we hypothesize that their extinction resulted from the rise of competitively superior crown-group taxa that today form massive colonies, consistent with Wilson and Hölldobler's concept of "dynastic succession."