Diverse and abundant terrestrial palynomorphs are recovered from a Frasnian-Famennian (F-F) succession of shales in the Ertych section, situated in central Armenia. They represent the first discovery of spores from the F-F shallow marine sedimentary sequences of the South Armenian Block, which at that time was part of the northern Gondwanan continental margin. Their taxonomic assessment recognizes 37 spore taxa assigned to 22 genera. Notably, the presence of Teichertospora torquata allows us to assign the entire studied succession to the torquata-gracilis zone, indicating a late Frasnian to early Famennian age. In addition, the occurrence of Acinosporites lindlarensis, which corresponds to the spores of the herbaceous lycophyte Leclercqia, suggests that the age of the studied succession should be further restricted to the late Frasnian. The presence of chitinozoans (i.e., Angochitina mourai) in the studied interval argues for marine deposition. Our biostratigraphic results provide a more coherent picture for the sedimentary evolution of this Frasnian- Famennian sequence arguing for a rather uninterrupted sedimentation close to the critical boundary interval. The identified spore assemblage highlights the close affinity of the Frasnian vegetation preserved in Armenia with other parts of the Northern Gondwana and southern Laurentia. We provide the first evidence of the occurrence of Kraeuselisporites ollii outside Canada and extend its known age range to the late Frasnian. (c) 2024 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The Early Devonian plant fossil record provides evidence of large vegetation turnover events in addition to rapid morphological and anatomical changes among vascular plants. The Ardenno-Rhenish Massif has historically yielded a vast number of these plant fossils allowing us to obtain a nearly unparalleled snapshot of Early Devonian vegetation. Nonetheless, the interest for describing or redescribing fossil floras from this region has waned in recent years despite their inherent value to understand Early Devonian plant diversity dynamics. Here, we describe a newly collected macrofossil flora from the middle Emsian Schuttbourg Formation at Consthum Quarry (Luxembourg). Six different plant macrofossil taxa were identified, including Drepanophycus spinaeformis and Psilophyton cf. princeps, in addition to putative macroalgal and fungal remains. The flora also includes other equivocal specimens resembling Sawdonia, Huvenia and Zosterophyllum. The composition of the assemblage is extremely similar, at generic level, to older Pragian-early Emsian and coeval floras from nearby localities, which indicates that there was no major floral turnover until the latter part of the Emsian in this region. Taxonomic descriptions also highlight many of the underlying issues in identifying Early Devonian sterile specimens. Inconsistencies in plant fossil identifications from this region call for a thorough revision of Belgian and German floras that together could provide a high-resolution picture of plant diversity changes in the Early Devonian.

The Upper Devonian Hongguleleng Formation is a significant stratigraphic unit near the Frasnian/Famennian and Devonian/Carboniferous boundaries of the Kazakhstan Paleoplate. However, its age is still under debate. A new palynostratigraphic analysis was conducted at the Gennaren section to provide a more accurate biostratigraphic assignment. In this study, we identified 43 species belonging to 26 spore genera, including those in open nomenclature. Despite the poor preservation of the palynofloras, the spore taxa were categorized into two assemblages. Assemblage I is established at the lower part of the lower member of the Hongguleleng Formation, containing Cornispora varicornata, cf. Auroraspora pseudocrista, and Cyrtospora cristifera. Assemblage II is from the upper part of the lower member of the Hongguleleng Formation, including Grandispora cornuta, Grandispora famennensis var. famennensis, Grandispora cf. famennensis var. minutus, Grandispora microseta, and Rugospora radiata. These assemblages are compared with the Western European DV Oppel Zone (lower-middle Famennian), and the GF to VCo Oppel zones. The assemblages are equivalent to the conodont crepida–rhomboidea and marginifera to Lower trachytera zones (middle-upper Famennian).

This paper describes dispersed cryptospores and trilete spores from tropical, temperate and cool climate belts within Přídolí and compares them with the land plant megafossil record. The palynology of earlier intervals in the Silurian are also reviewed. A common feature of the cryptospore and trilete spore records is that their number is surprisingly lowest in the tropical climatic belt and much higher in the temperate and especially in the cool latitude, and the highest number of cryptospore taxa occurring only in one belt is found in the cool belt while the highest number of trilete spore taxa that occurred only in one belt is recorded in the temperate belt. In general, based on the dispersed spore record, we can estimate that the plant assemblages of the tropical belt were dominated by rhyniophytes; trimerophytes probably prevailed over rhyniophytes in the temperate belt, and rhyniophytes again dominated within the cool belt.

The Lower Devonian Klerf Formation is an exceptional Konservat-Lagerstatte, exposed at multiple sites in the Waxweiler region in the Eifel area, western Germany. It has been studied for its various fossils, mainly arthropods, fishes, plants, molluscs, brachiopods and crinoids. At Waxweiler, the strata are palaeoecologically interpreted as a prograding deltaic depositional system elongate from NW to SE in the Ardenno-Rhenish area. The Klerf Formation has, however, not been studied in full in terms of its microflora and microfauna. Our study of the formation from two different quarries in the Waxweiler area yielded fairly diverse miospore assemblages dominated by abundant organic matter in varying degrees of coalification. The miospore assemblages are mainly composed of classic Lower Devonian taxa of the Old Red Continent (Laurussia). These belong, among others, to the genera Ambitisporites, Apiculiretusispora and Retusotriletes. Biostratigraphically more important species recovered include Acinosporites lindlarensis, Apiculiretusispora brandtii, Cymbosporites asymetricus, Diatomozonotriletes franklinii, Emphanisporites annulatus, Verruciretusispora dubia and Verrucosisporites polygonalis. In addition, Emphanisporites foveolatus, which is known only from a limited area in the Ardenno-Rhenish region, is also identified, indicating an earliest Pragian to middle Emsian age for the composite section. These assemblages are found to be accompanied by reworked phytoplankton to a much lesser extent. Our results reveal a much larger palaeobotanical diversity from the Rhineland outcrops than previously known, indicating a well-developed Psilophyton-type vegetation with related plants. The results further suggest a likely presence of plants such as Leclercqia and Pertica.

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Dispersed spore assemblages are described from the Early Devonian (late Lochkovian-late Emsian) Rañeces Group (Asturias) and equivalent La Vid Group (Leon) of Northern Spain. The lower part of both groups consists predominantly of limestone and yields only impoverished palynological assemblages. However, the upper parts contain more clastic sediments and yield rich assemblages of well preserved palynomorphs. These are dominated by marine forms but also include abundant spores. Sixty-two spore taxa are reported from the Valporquero Formation (Leon). These all belong to a single assemblage that can be equated with the lindlarensis-sextantii Assemblage Zone (mid-early late Emsian age) erected in northern Gondwana. The sequences are independently age constrained by conodont and invertebrate macrofossil evidence and the ages derived from these studies are concordant with the assigned spore zones. The Spanish spore assemblages are from deposits that accumulated around the Armorican Terrane Assemblage (ATA), a group of islands that lay between the continents of Laurussia and Gondwana. Jacaard Index analysis indicates that the Valporquero Formation spore assemblage is endemic, and not closely related to those previously described from Laurussia or Gondwana, although it has more in common with the latter. This suggests that the Armorican Terrane Assemblage was widely separated from both Laurussia and Gondwana, but was located closer to and had more connectivity with Northern Gondwana.

Assemblages of cryptospores were reported and detailed for the first time from the Upper Ordovician from Brazil. These assemblages were recovered from diamictites and shales with dropstones of the Iapó Formation, Rio Ivaí Group, Paraná Basin. The analyzed sequence represents the Hirnantian glacial deposits containing well-preserved palynomorphs with low thermal maturity and low total organic carbon. The cryptospore assemblages comprise monads, dyads, permanent tetrads, and polyads, naked or enclosed in an envelope, totalizing 17 species. The associated marine palynomorphs consist of 12 species of acritarchs and prasinophycean algae which are not discussed in detail herein. It is noticied the occurrence of Tortotubus protuberans and abundant black fragments at the lowermost portion of diamictites. The Late Ordovician cosmopolitan assemblages of cryptospores corroborate the early radiation of the land plants in western Gondwana. These results contribute to a better knowledge of Late Ordovician in Brazil and more generally in South America.

The oldest reported occurrence of cryptospores supposed to derive from land plants (embryophytes) is currently considered to be in the Middle Ordovician. The two genera Virgatasporites and Attritasporites, described in the 1960MODIFIER LETTER PRIMEs from the Early Ordovician (Tremadocian) of Algeria, are morphologically close to the miospores, and therefore pose a dilemma, because these spore-like microfossils are recorded before the first appearance of the oldest land plant derived spores. Here the taxonomy, biostratigraphy and palaeobiogeography of the two genera and their species are revised. Both genera are found in many localities on the Gondwanan border between the late Cambrian and the Middle Ordovician. They have not been found at the margins of other palaeocontinents so far. The biological affinity of the taxa remains uncertain. Several authors considered the two genera to be spore-like microfossils, whereas other authors classified them as acritarchs, i.e. organic-walled microfossils of unknown biological affinity. As the relationship to the embryophyte lineage cannot be established clearly to date, the biological affiliation remains enigmatic. Therefore, in the absence of other evidence, the taxa Virgatasporites and Attritasporites should be temporarily classified as incertae sedis, i.e. as acritarchs, before their true biological affinity is known and they can be adequately placed into a biological group.

The depositional succession of the Ponta Grossa Formation (Paraná Basin) corresponds to a wave-dominated shallow-marine environment, represented by four coarsening-upwards cycles, limited by flooding surfaces. Previous studies on a well-preserved and diverse assemblage of miospores indicated a late Pragian to possibly middle Emsian age. The palynological analysis of the Jaciara section is completed herein with the analysis of the marine fraction, composed of highly abundant and diverse organic-walled phytoplankton, with 222 species recognized. Preservation and abundance of some species, that were previously informally described or mentioned, are here formally described. Additionally, two new species are instituted: Pterospermella jaciarense sp. nov. and Florisphaeridium brasiliensis sp. nov. The phytoplankton species, such as Bimerga paula, B. sp. aff. B. bensonii, B. nuda, Cordobesia oriental, C. uruguayensis, Palacanthus ledanoisii, Pyloferites escobaides, P. paranaensis and Winwaloeusia distracta, recorded in the lower part of the section, indicate a late Pragian age, in coincidence with the miospore age. Navifusa spp. and Pterospermella pernambucensis first appear in the middle part of the studied section, suggesting an Emsian age, as do the miospores. The diversity and preservation quality of the phytoplankton tend to decrease towards the top of the section, probably related to a general shallowing trend.

The Rhynie chert (Aberdeenshire, Scotland, UK) plant Horneophyton lignieri is likely one of the most studied elements of Lower Devonian floras considering both macro and microremains. Intriguingly, while larger plant fragments are exceptionally fossilized, in situ spores are not necessarily well-preserved in the chert: they are dark brown and intensively torn overall. However, spore masses are often dominated by single spores, which can be taxonomically attributed. Mainly, Horneophyton spores have been described as belonging to Apiculiretusispora type and Emphanisporites cf. decoratus, this last one being currently accepted in general. Here, we document new Horneophyton spore morphologies, that are sometimes quite different. Such morphologies include, but are not restricted to, Ambitisporites, Dibolisporites or Retusotriletes. All these observed spore morphotypes belong to the same palaeobiological entity, as they have been found in the same parent plant. These findings show that the sporangia of a same plant species may deliver diverse taxa of coeval isolated spores. But most importantly, if these spores are found in sediments, they would most probably be identified as different dispersed miospore taxa. This highlights that caution is needed when comparing plant diversity with the dispersed spore fossil record. Moreover, we confirm the presence of Emphanisporites decoratus inside most of the sporangia of Horneophyton lignieri, and its high morphological variability. We further discuss the role of the different states of maturation and preservation, as well as taphonomy-induced features, on observed spore diversity.

Gondwanan floras of Late Devonian age are poorly known. In Australia, the rare studies that have been published on Late Devonian plants are old and need reinvestigation. This paper is an account of the plant macro- and micro-remains found in the Mandowa Mudstone at Barraba, New South Wales. According to the miospores, plants are late to latest Famennian in age. The record of anatomically preserved specimens is diversified, with nine taxa assigned to the Lycopsida, Cladoxylopsida, Iridopteridales and Archaeopteridales. One specimen is referrable to the spermatophytes. Several taxa are specific to Barraba, i.e., the lycopsid genera Cymastrobus and Lycaugea, the iridopteridalean genus Keraphyton, the cladoxylopsid species Polyxylon australe, and possibly a plant represented by a large Hierogramma branch showing exarch protoxylem strands. The adpression record is dominated by axes of the cosmopolitan lycopsid genus Leptophloeum. It also includes specimens interpreted as seed plants such as a possible ovule resembling Pseudosporogonites, and two types of foliage differing by their petiole width. One of this foliage consists of delicate fronds broadly comparable to those of Cosmosperma. The closest flora from Barraba is the late Famennian–earliest Tournaisian flora of the New Albany Shale in eastern USA, suggesting floral connexion and comparable environmental conditions between Northern Gondwana and Southern Laurussia.

An integrated palynological and geochemical approach has been initiated to date and to precise the geochemical events of the Pimenteiras Formation, in the Late Devonian from the Parnaíba Basin, Brazil. Based on good biostratigraphic markers and presence of index species among miospores, acritarchs and chitinozoa, the investigated sequences are referred to the Middle to early Late Frasnian. Among Miospores, Chelinospora concinna and Verrucosisporites bulliferus are likely to be from the BPi Interval Zone defined in the Amazon Basin. Chitinozoans of the Early to early Late Frasnian Angochitina (Lagenochitina) avelinoi zone of the Parnaíba Basin are present, and acritarch assemblages are also consistent with a Middle to early Late Frasnian age, by comparison to assemblages previously described in other Brazilian basins. Some important accompanying species of palynomorphs are illustrated. In the studied outcrops, black shale intervals are referred to top of the Radioactive Sale B and Radioactive Shale C according to Rodrigues (1995) definitions. Top of Radioactive Shale B shows good concentration of terrestrial organic matter, but low potential source of gas. By comparison Radioactive Shale C of the upper part of the Pimenteiras Formation, with important concentration of marine organic matter have low to high potential as source of gas and condensate. This study shows that a progressive flooding took place during the Devonian period in the Parnaíba Basin with maximum marine transgression in the Frasnian. These global events of interest for hydrocarbon exploration, are regarded as markers for Gondwanan regional chronostratigraphic correlations.

Accurate palyno-analysis by S. Loboziak (from 1980 to 1983) of 28 samples from the Upper Givetian to the Middle Frasnian Blacourt, Beaulieu and Ferques Formations and of 44 samples of the Upper Frasnian to the Lower Famennian Hydrequent Formation are re-evaluated. Chelinospora concinna, Verrucosisporites bulliferus, Cirratriradites jekhowskyi, Lophozonotriletes media first occurrences are major criteria for Lower and Middle Frasnian, well calibrated by conodonts. Cymbosporites acanthaceus, Rugospora bricei, Grandispora gracilis, Diducites plicabilis, Corbulispora vimineus first occurrences allow to subdivide the Upper Frasnian where conodonts are poorly present. Samarisporites triangulatus versus Auroraspora pseudocrista taxonomy and stratigraphic significance are discussed. The reconnaissance borehole Nieuwkerke-De Seule (95W152), near the limit of the Upper Palaeozoic subcrop on the Brabant Massif (West Flanders, Belgium, 75 km east of the Boulonnais), which has intersected conodont-dated Givetian/Frasnian boundary at the transition between the Bois de Bordeaux and Bovesse Formations, contained poorly preserved miospores attributed to the triangulatus–concinna (TCo) Oppel Zones. In the nearby Nieuwkerke-Noordhoek borehole (95W153), strata also assigned to the Bovesse Formation yielded better preserved miospores which demonstrate a close succession of triangulatus–concinna (TCo) and bulliferus–jekhowskyi (BJ) Oppel Zones at the transition Lower–Middle Frasnian, also known in the Beaulieu Formation in the Boulonnais. Samples from the Heuvelland groundwater monitoring well (95W175), 10 km north of Nieuwkerke, contain the bricei-acanthaceus (BA) Oppel Zone suggesting a late Frasnian age, also known in the Hydrequent Formation in the Boulonnais area and in the Booischot Formation in the Booischot borehole (59E146) from the Campine Basin (Belgium). International correlation using Frasnian miospore zonation is attempted between the Pripyat Depression in Belarus, the Timan–Pechora province in Russia and North-West China.

The present study concerns the palynology (mainly miospores), and geochemistry of the Jaciara section, situated 5 km from the town of Jaciara, Mato Grosso, in the Parana Basin of Brazil. The age of this outcrop is considered to be Early Devonian. A study of the whole assemblage has highlighted a diversified association of miospores. Their distribution throughout the samples is somewhat erratic, which sometimes complicates the determination of the biostratigraphic attribution. However the following markers have been identified: Apiculiretusispora brandtii, Brochotriletes bellatulus, Cymbohilates baqaensis, Cymbosporites asymtnetricus, Cymbosporites wellmanii, Devonomonoletes sp. 1 in Breuer and Steemans (2013), Dibolispotites sp. 2 in Breuer and Steemans (2013), Dictyotriletes subgranifer, Distaverrucosisporites steemansii, Latosporites ovalis, Scylaspora costulosa, Verrucosisporites nafudensis, Verrucosisporites onustus, Verruciosisporites stictus, Zonotriletes brevivelatus, and Zonotriletes simplicissimus. The finding of these miospores allowed recognition of the following biozones established in Saudi Arabia: the papillensis-baqaenisis Biozone, Pragian in age; the ovalis-biornatus Biozone (ovalis, milled, asymmetricus subzones), late Pragian to early Emsian in age: and possibly the lindlarensis-sextantii Biozone, middle Emsian in age. The presence of many taxa in common with other Gondwana n basins, particularly those from Saudi Arabia, North Africa and South America, corroborates the paleogeographical relationship between different regions of Gondwana, even between those located in very different paleolatitudes. New geochemical analyses were also performed and add more information toward the understanding of the local paleoenvironmental evolution. (C) 2019 Elsevier B.V. All rights reserved.

It is revealed that the lowest 1010 m of the Saint-Ghislain borehole (-4393 to -5403 m), of which cuttings are available, constitutes a crucial source of information to investigate, amongst others, the deep geothermal potential within the Brabant Parautochthon, underlying the Mons Basin, Hainaut. The lithological succession of this interval was reconstructed based mainly on visual analysis and calcimetry of 852 cutting samples as well as four cored sections. Additionally, palynological, magnetic susceptibility and X-ray diffraction analyses were conducted in order to complement the dataset. The lower section of the investigated borehole sequence mainly consists of grey calcareous shale while the middle section is dominated by blue-grey shaly limestone and the upper section is mainly composed of green shale. Palynomorphs found at -5261 m suggest a latest Givetian–Early Frasnian age. A new lithostratigraphical interpretation of the deepest part of the Saint-Ghislain borehole is proposed. The lower calcareous shale from ‑5403 to ‑5100 m is interpreted as the Bovesse Formation (Lower Frasnian) and at its base possibly uppermost Givetian. The overlying limestones from -5100 to -4790 m can be attributed to the Rhisnes Formation (Upper Frasnian), and the green shale between ca. -4393 and -4790 m, to the Bois de la Rocq Member (Famennian). These results open new insights regarding the geological interpretation of the basement underlying the Mons Basin. They also present a promising approach and example regarding interpretations based on cuttings.