Background The modern chironomid fauna of New Zealand is diverse, highly endemic and reflects a complex biogeographical history. This fauna has been important for developing phylogenetic and biogeographic concepts including Brundin’s writings on transantarctic relationships but until now the fossil record to support these reconstructions has been very limited. Here we describe the first fossil species of Chironomidae, subfamily Orthocladiinae, from New Zealand, based on inclusions in amber from the late Oligocene Pomahaka Formation of the South Island. Methods We examined newly excavated fossil tree resin (amber) from the late Oligocene Pomahaka Formation in southern New Zealand for inclusions. Amber pieces containing chironomids were prepared and morphologically investigated using light-microscopy and µCT-scanning. Specimens were taxonomically evaluated using identification keys for modern adult chironomid midges. Habitus and key morphological features of each specimen were documented photographically and/or by line drawings. Results Thirteen Chironomidae specimens from Pomahaka amber were identified as members of the subfamily Orthocladiinae Kieffer. Bryophaenocladius zealandiae sp. nov. Baranov is the first Southern Hemisphere fossil of the genus. Bryophaenocladius Thienemann, 1934 is absent from the extant fauna of the main islands of New Zealand; however, it may be present on the subantarctic Auckland Islands. Two incompletely preserved specimens are described as Morphotype 1 cf. Bryophaenocladius zealandiae. Based on a male adult, Pterosis extinctus sp. nov. Baranov is described as the first fossil record of the extant genus Pterosis Sublette and Wirth, today represented by a single endemic species on the New Zealand subantarctic Auckland Islands and Campbell Island. Two female adult specimens are described as Morphotype 2 cf. Metriocnemini. The new fossils of the genera Bryophaenocladius and Pterosis belong to chironomid taxa requiring terrestrial or semi-aquatic habitats for larval development, supporting the notion of a humid forest swamp paleoenvironment for the Pomahaka amber source forest.

Recently, we redescribed an amber inclusion from mid‐Cretaceous Kachin amber of Myanmar, previously assigned to the extant genus Phylica in Rhamnaceae (core eudicots), and placed it in a new fossil‐genus, Nothophylica . Based on our reconstructions, we identified new floral features and instead suggested affinities within magnoliids, especially Laurales. Using parsimony phylogenetic analyses, we here substantiate that Nothophylica piloburmensis does not possess any affinities with eudicots but shares unequivocal similarities with Laurales. Our results place Nothophylica sister to Lauraceae and Hernandiaceae.

Among extant lycophytes, Selaginella (Selaginellaceae, spike mosses) is the most species-rich genus, with over 700 described species. The evolutionary history of this lycophyte genus dates back to the Carboniferous or even Devonian; however, amber-preserved Selaginella fossils were previously only described from mid-Cretaceous amber from Myanmar. Here, we report the first fossil from Miocene Dominican amber attributable to Selaginella based on macromorphological characters and compare the fossil morphology to extant species of the genus. Selaginella jorelisiae sp. nov. can be identified based on the presence of symmetric ovate dorsal trophophylls with scattered teeth or cilia at the margins and an aristate apex, and ventral elliptic trophophylls with an apiculate apex and rounded base, with cilia on the acroscopic proximal margin and teeth all along the rest of the margin. Fossil and subfossil Selaginella representatives from the Greater Antilles have been described based on middle Oligocene, Pleistocene, and Holocene microspores or megaspores. Selaginella jorelisiae fills a gap in the local fossil record as it represents the first evidence of Selaginellaceae from the Miocene of these islands. While the previously discovered rich cryptogamic diversity from Dominican amber is considered to represent epiphytic communities, S. jorelisiae was most likely a component of the herbaceous layer of these humid tropical forests.

Dominican amber (15–20 Ma) and Mexican amber (15–23 Ma) are valuable sources of fossil epiphytic bryophytes, ferns, and lichens. Both ambers derive from resins of Hymenaea, a genus in the Fabaceae family still occurring in Mexico, Central America, and the Caribbean today. The amber inclusions provide rare glimpses into Miocene neotropical epiphyte communities in life-like preservation. In this study, we extend the fossil record of these communities and describe Frullania chiapasensis and Thysananthus patrickmuelleri, two new fossil species of leafy liverworts from Mexican amber. Frullania chiapasensis is the fourth representative of this genus from tropical amber. The genus Thysananthus is rather diverse in Dominican amber, and it is here newly recorded from Mexican amber. Additionally, we treat five new fossils at genus level, including one leafy liverwort (Lejeunea sp.) as well as three lichens from Dominican amber and one lichen from Mexican amber, all belonging to the extant genus Parmotrema. All four cryptogamic genera are common extant elements of tropical and subtropical forests. The new fossil evidence substantiates that Miocene neotropical cryptogamic communities were very similar to extant ones at generic level.

Of the early Eocene amber deposits known across the world, Belgian amber has been mostly absent from the relevant literature. We reinvestigated amber held in the palaeobotanical collection of the Royal Belgian Institute of Natural Sciences, Brussels, which derived from three localities in Belgium that originated from two geographical areas (Leval-Trahegnies and Orp-le-Grand). Using Fourier transform infrared (FTIR) spectroscopy we show the close chemical relationship of Belgian amber to the early Eocene Oise amber from the Paris Basin, and highlight the potential effect of weathering on the amber chemistry. The amber derives from a very similar botanical source as the Oise amber (Combretaceae or Leguminosae-Caesalpinioideae), but from different coeval basins. The two Leval-Trahegnies localities provided amber that exhibit different stages of weathering (heavily fissured and crazed, darkened) and lacking any inclusions. The Orp-le-Grand locality provided the least weathered amber, with one amber piece containing two inclusions: a mite and a new genus and species of hemipteran (Cativolcus uebruum gen. et sp. nov.), and a second one that preserved the impression of insect wings pressed into the surface.

Background Phasmatodea are well known for their ability to disguise themselves by mimicking twigs, leaves, or bark, and are therefore commonly referred to as stick and leaf insects. In addition to this and other defensive strategies, many phasmatodean species use paired prothoracic repellent glands to release defensive chemicals when disturbed by predators or parasites. These glands are considered as an autapomorphic trait of the Phasmatodea. However, detailed knowledge of the gland anatomy and chemical compounds is scarce and only a few species were studied until now. We investigated the repellent glands for a global sampling of stick and leaf insects that represents all major phasmatodean lineages morphologically via µCT scans and analyzed the anatomical traits in a phylogenetic context. Results All twelve investigated species possess prothoracic repellent glands that we classify into four distinct gland types. 1: lobe-like glands, 2: sac-like glands without ejaculatory duct, 3: sac-like glands with ejaculatory duct and 4: tube-like glands. Lobe-like glands are exclusively present in Timema , sac-like glands without ejaculatory duct are only found in Orthomeria , whereas the other two types are distributed across all other taxa (= Neophasmatodea). The relative size differences of these glands vary significantly between species, with some glands not exceeding in length the anterior quarter of the prothorax, and other glands extending to the end of the metathorax. Conclusions We could not detect any strong correlation between aposematic or cryptic coloration of the examined phasmatodeans and gland type or size. We hypothesize that a comparatively small gland was present in the last common ancestor of Phasmatodea and Euphasmatodea, and that the gland volume increased independently in subordinate lineages of the Occidophasmata and Oriophasmata. Alternatively, the stem species of Neophasmatodea already developed large glands that were reduced in size several times independently. In any case, our results indicate a convergent evolution of the gland types, which was probably closely linked to properties of the chemical components and different predator selection pressures. Our study is the first showing the great anatomical variability of repellent glands in stick and leaf insects.

Premise: Molecular studies based on chloroplast markers have questioned the monophyly of the fern genus Pecluma (Polypodioideae, Polypodiaceae), which has several species of Polypodium nested within it. We explored the delimitation of Pecluma and its biogeographic pattern by evaluating the phylogenetic position of four Polypodium species not sequenced thus far and integrating the first fossil evidence of Pecluma. Methods: Using herbarium material, we applied a genome-skimming approach to obtain a phylogenetic hypothesis of Polypodioideae; assessed the combination of character states observed in the fossil from Miocene Dominican amber using a previously published phylogeny of Polypodioideae based on four plastid markers as framework; calculated divergence times; and conducted an ancestral area estimation. Results: Within Polypodioideae, Pecluma was recovered as sister to Phlebodium. Three of the newly sequenced species-Polypodium otites, P. pinnatissimum, and P. ursipes-were recovered with maximum support within the Pecluma clade, whereas P. christensenii remained within Polypodium. The closest combination of character states of the fossil was found within Pecluma. Our biogeographic analyses suggest an Eocene origin of the genus in South America, with several subsequent Oligocene and Miocene colonization events to Mexico-Central America and to the West Indies. Conclusions: Although the circumscription of Pecluma is still challenging, our results elucidate the origin and age of the genus. The newly described fossil, Pecluma hispaniolae sp. nov., supports the hypothesis that the epiphytic communities of the Greater Antilles exhibit a constant generic composition since the Miocene. We propose new combinations (Pecluma otites, Pecluma pinnatissima, and Pecluma ursipes) to accommodate three species previously classified in Polypodium.

Many calicioid fungi accumulate ascospores into an adhesive mass, called the mazaedium, at tips of stipitate apothecia. Fossil specimens from European ambers demonstrate that this morphology had evolved by the Paleogene and has since remained unchanged. The conserved maintenance of a spore-saving strategy is probably linked to animal-vectored dispersal, but experimental evidence confirming this is lacking. Here, we approached the question with a series of experiments, in which ascomata of three distantly related calicioid species were exposed to living individuals of four insect species. The results confirmed that calicioid ascospores are readily attached to any insects that touch the mazaedial spore mass. Adhered ascospores could be recovered from insect surfaces with ultrasonic cleaning. We found no significant differences in the amounts of attached ascospores of different fungal species. We discuss the new findings in the context of previous observations supporting the ecological and evolutionary role of animal-vectored dispersal in calicioid fungi.

The order Mycocaliciales (Ascomycota) comprises fungal species with diverse, often highly specialized substrate ecologies. Particularly within the genus Chaenothecopsis, many species exclusively occur on fresh and solidified resins or other exudates of vascular plants. In New Zealand, the only previously known species growing on plant exudate is Chaenothecopsis schefflerae, found on several endemic angiosperms in the family Araliaceae. Here we describe three new species; Chaenothecopsis matai Rikkinen, Beimforde, Tuovila & A.R. Schmidt, C. nodosa Beimforde, Tuovila, Rikkinen & A.R. Schmidt, and C. novae-zelandiae Rikkinen, Beimforde, Tuovila & A.R. Schmidt, all growing on exudates of endemic New Zealand conifers of the Podocarpaceae family, particularly on Prumnopitys taxifolia. Phylogenetic analyses based on ribosomal DNA regions (ITS and LSU) grouped them into a distinct, monophyletic clade. This, as well as the restricted host range, suggests that all three taxa are endemic to New Zealand. Copious insect frass between the ascomata contain ascospores or show an early stage of ascomata development, indicating that the fungi are spread by insects. The three new species represent the first evidence of Chaenothecopsis from any Podocarpaceae species and the first from any gymnosperm exudates in New Zealand.

Distributions of neuronal activity within cortical circuits are often found to display highly skewed shapes with many neurons emitting action potentials at low or vanishing rates, while some are active at high rates. Theoretical studies were able to reproduce such distributions, but come with a lack of mathematical tractability, preventing a deeper understanding of the impact of model parameters. In this study, using the Gauss-Rice neuron model, we present a balanced-state cortical circuit model for which the firing rate distribution can be exactly calculated. It offers selfconsistent solutions to recurrent neuronal networks and allows for the combination of multiple neuronal populations, with single or multiple synaptic receptors (e.g. AMPA and NMDA in excitatory populations), paving the way for a deeper understanding of how firing rate distributions are impacted by single neuron or synaptic properties.

The fossil fern species Cretacifilix fungiformis from mid-Cretaceous Kachin amber from Myanmar was previously assigned to eupolypod ferns for having sporangia with a vertical annulus and sporangial stalks 2–3 cells thick, along with monolete spores with a distinct perine. However, due to the insufficient documentation of character states and the unavailability of the holotype, the proposed affiliation of this fossil to derived families of eupolypods required further study. The recent discovery of additional leaf fragments of C. fungiformis from the same amber deposit enabled us to re-evaluate the relationships of this fossil taxon. Newly documented morphological evidence corroborated its placement within the eupolypod ferns. This was achieved by evaluating identifiable features present in the fossil species through an ancestral character state reconstruction utilizing a comprehensive, time-calibrated phylogeny of eupolypod ferns. Our character state reconstruction of extant eupolypod families and genera recovered morphological similarity of Cretacifilix to the closely related genera Arachniodes and Dryopteris, supporting an assignment of this fossil genus to the species-rich family Dryopteridaceae within the Polypodiineae.

The fossil record of bryophytes from worldwide amber deposits substantially increased within the past decade. Inclusions of mosses have now been described from 15 Cretaceous and Cenozoic amber localities. These fossils stand out by their excellent preservation and are therefore very valuable for divergence time estimates as well as for the reconstruction of the evolution of morphological traits through time. The amber inclusions are three-dimensional and show diminutive details which are crucial for classification of bryophytes. Many moss fossils preserved in amber were convincingly assigned to extant genera and, in the case of Miocene taxa, sometimes even to living species. Here, we describe a fossil Leucobryum from Zhangpu amber of southeastern China. The extant genus Leucobryum comprises between 35 and 83 mainly tropical species and is characterized by a highly modified costa consisting of one layer of small chlorocysts between two layers of large, empty leucocysts. Some leaves of the fossil specimens are broken and show the arrangement of cells typical for extant species. We provide a thorough comparison to extant representatives, however, as several characters necessary for assignment at species level are not accessible in the fossil, it is uncertain whether it represents an extinct or extant species.