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Calcium oxalate (CaOx) is one of the most common bio-mineral in extant plants and is believed to serve a variety of functions such as calcium storage and herbivore defense. However, traces of CaOx crystals have rarely been identified in fossil plants, and they are primarily known from fossil gymnosperms, where empty cavities of former CaOx crystals or ghost crystals have been reported from leaf cuticles of some Late Cretaceous and Cenozoic conifers. Here we investigate fossil angiosperm leaves from the late Oligocene Rott Fossil Lagerstätte and report ghost crystals of various shapes, sizes and topology (distribution patterns), and cavities. These micromorphological structures of fossil leaves are compared to CaOx deposits in leaves of extant plants: globular structures in fossil leaves resemble CaOx druses (crystal aggregates) in fresh leaves in size and distribution; and angular or brick-shaped structures in the vascular system of fossil leaves closely resemble prismatic CaOx crystals in the vascular system of extant leaves in both size and topology. Chemically, CaOx druses have survived fossilization as cavities only, and were replaced by organic matter and ghost minerals containing Ca, Si, Al, S, and Fe. The identification of former CaOx remains in leaf fossils provides novel insights on the fate of plant bio-minerals during fossilization. More importantly, it provides an additional aspect of the ecophysiology of fossil plants thus improving the accuracy of palaeoecological reconstructions and can provide a broader perspective on the evolution of CaOx and their rule in plant ecology across geological timescales. Alternative interpretations of the fossil microstructures are discussed but ruled out. [ABSTRACT FROM AUTHOR]

The Geiseltal biota is an Eocene lacustrine Konservat‐Lagerstätte in central Germany. Despite its rich fauna and flora (over 50 000 fossil vertebrates, insects and other invertebrates, plants and trace fossils) the taphonomy of the biota, and of the anurans in particular, is poorly understood. We analysed the skeletal taphonomy of 168 anurans, scoring each specimen for orientation, completeness and articulation. Most are partial skeletons, truncated during preparation. This process introduces measurable artefacts into the taphonomic data, which requires further study. We identified recurring taphonomic states, including disarticulation or loss of abdominal bones, loss of one or more limbs, extensive disarticulation, and extensive loss of elements across the body. Relatively rare states include: loss of distal limb elements only, scattered bones, and isolated, articulated limbs. These data inform a new taphonomic model for the Geiseltal anurans. Comparative analysis of patterns in completeness and articulation in these specimens and anurans from other Cenozoic Lagerstätten reveals repeated patterns in preservation in lacustrine‐hosted settings, such as proximal to distal trends in completeness, preferential loss of small peripheral bones, disarticulation of abdominal bones, and reorientation of major body regions. Taphonomic controls in lacustrine systems are surface water temperature, lake depth, vegetation, exposure to bottom currents, transport mechanisms, scavenging, decay regime, bone size and location in the skeleton; all ultimately controlled by palaeoclimate, lake physiography and hydrology, and anuran anatomy. A universal approach to quantitative analysis of skeletal taphonomy metrics will enable comparative testing of the relationship between preservation and palaeoenvironment for diverse fossil vertebrates. [ABSTRACT FROM AUTHOR]

Summary: We describe the first evidence of fossil Abies wood from the late early Miocene fossil plant assemblage of Wiesa in east Germany. The comparatively well-preserved piece of xylitic wood was recovered in the kaolin quarry at Hasenberg hill in Wiesa. The Wiesa assemblage is characterized as being allochthonous and partly parautochthonous mass deposits of diaspores, leaves, and wood. The latter component is rather incompletely studied so far. The described fossil is characterized by high rays, mostly uniseriate bordered pits, generally thick and pitted horizontal and tangential ray cell walls, but also partly smooth horizontal ray cell walls, absence of ray tracheids, the occurrence of traumatic resin canals, and rare occurrence of axial parenchyma of two types. This type of fossil wood has been described as Abietoxylon shakhtnaense Blokhina from the Oligo-Miocene of Sakhalin, Russia. Due to nomenclatural issues of Abietoxylon a recombination to Cedroxylon Kraus emend. Gothan is proposed following common practice for affiliation of abietoid fossil wood of Cenozoic age. Cedroxylon shakhtnaense comb. nov. shares anatomical characteristics with the wood of extant Abies Mill., in particular with sections Abies and Grandis , and is most closely related to section Grandis. The properly preserved fossil wood from Wiesa provides the opportunity of applying qualitative and quantitative analyses for testing and discussing its placement in relationship to intra-tree variability and ontogenetic aspects. The first evidence of fossil wood of Abies from Wiesa confirms again the presence of the genus in mid-latitude subtropical zonal vegetation during the beginning of the Miocene Climatic Optimum. [ABSTRACT FROM AUTHOR]

Petrified woods from the Kyffhäuser (Siebigerode Fm., Saale Basin) are among Germany's most voluminous occurrences of petrified trees. We reconstruct the provenance and fossilisation of the silicified logs and accompanying fossil plants based on sediment architectures documented in 15 quarries, plant-anatomical analyses of 112 specimens from eight collections and cathodoluminescence microscopy of silicified tissues. The up to 20 m long Agathoxylon trunks derived from 40 m tall cordaitaleans and conifers. Alluvial processes, the erosion of adjacent basement slopes during floods and storms were the main forces to recruit large woody debris from seasonally dry forests growing in extrabasinal habitats. A climatically controlled high discharge variability and the large-scaled, low-sinuous channel geometry ensured transport of the trunks across a 60 km distance towards the basin centre. Deposition of the logs occurred during the waning flood stage accompanied by the formation of four large woody debris-induced sedimentary structures. The stratigraphic occurrence of silicified trunks indicates a hydrodynamic window of log entombment constrained by river morphology, discharge regime, wood shape, and wood density. The synsedimentary to early postsedimentary silicification was a millennium-scale twophase process and resulted in selective tissue preservation referred to as "pointstone". Imprints from associated floodplain deposits reveal sparse riparian vegetation consisting of ferns, calamitaleans, pteridosperms, and juvenile to shrub-like cordaitaleans. Results demonstrate the potential of multidisciplinary approaches in interpreting plant taphocoenoses and highlight the Kyffhäuser as a crucial locality to elucidate late Palaeozoic vegetation dynamics. [ABSTRACT FROM AUTHOR]

• First combined functional leaf traits – insect folivory study of Paleogene floras. • Insect damage types indicate diverse fauna in coastal lowland habitats. • Mean leaf mass per area is similar to that of extant evergreen subtropical forests. • Application of Trait Combination Type approach revealed distinct "fingerprint". • CLAMP, CA and LMA estimates of palaeoclimate parameters coincide very well. Leaves as main locations of photosynthesis show various adaptations of morphological and anatomical traits to habitat conditions. By implication, leaf traits of fossil dicotyledonous plants can be used as proxies for reconstructions of palaeoenvironmental and palaeoclimatic conditions. Herein, a Paleogene leaf flora, the Profen-Süd LC assemblage from central Germany, is introduced and its leaf traits are outlined. Based on a preliminary phytosociological analysis, a floristic evaluation with respect to modern comparative vegetation refers to azonal communities predominated by a Rhodomyrtophyllum - Steinhauera riparian association. It mirrors local rather but species-divers vegetation. Morphological (shape; margin; venation) and morphometrical (area; leaf mass per area) leaf parameters are determined on a representative subsample and applied to the Trait Combination Type (TCT) analysis for gross-morphological characterization of fossil leaf assemblages, and to quantitative methods for estimation of palaeoclimate parameters: C limate L eaf A nalysis M ultivariate P rogram, C oexistence A pproach and L eaf M argin A nalysis. As a result the assemblage contains only four out of 16 TCTs. Morphological diversity is assumed to be characteristically low as the TCT pattern is not fundamentally distinct from that of the coeval hinterland flora of Kučlin (Czechia). Leaf size is overwhelmingly microphyll, and leaf mass per area values are in accordance with present-day evergreen forests. Main results refer to a sclerophyllous evergreen broad-leaved forest. All palaeoclimate calculations deliver similar estimates for subtropical climate with frost-free winters and humid conditions but certain seasonality in precipitation. Results are briefly discussed in context to depositional environment and taphonomic aspects. Moreover, traces of insect herbivory on the fossil leaves are treated as additional traits beyond classical parameters. Respective patterns are briefly documented and discussed to obtain deeper insights into ecosystem structure and food webs. Finally, this case study gives rise to several open questions about reliability and meaningfulness of fossil leaf traits and the feasibility in palaeoecological investigations. [ABSTRACT FROM AUTHOR]

The smooth Siphonia bovista Gein. from the Saxonian Cretaceous Basin, introduced as a siliceous sponge by Hanns Bruno Geinitz in 1871, is interpreted as the simple internal mould of the cone-like plant fossil Dammarites albens Presl in Sternberg, 1838, representing the composite mould of the same organism, just in different preservation. Apart from the globular to egg-shaped outline, the size ratios and the same laterally flattened compaction, especially the basal area around the short stalk which is arched inwardly forms a characteristic feature of the taxon. Cone-like plant bodies and leaves of the salt-tolerant dwarf gymnosperm D. albens are always found in the lowermost marine sandstones of the Bohemian and Intrasudetic Cretaceous basins (Middle-Upper Cenomanian), overlying fluviatile to brackish strata. The same is true for "S. bovista": all Saxonian specimens were found in the lower Upper Cenomanian Unterquader of the Oberhäslich Formation, overlying the brackish Wurmsandstein of the uppermost Niederschöna Formation. Environment, sedimentary conditions and stratigraphic position of the smooth preservation form Siphonia bovista Gein. and the cone-like plant bodies of Dammarites albens Presl in Sternberg of Germany, the Czech Republic and Poland are thus identical. The species name Siphonia bovista Geinitz, 1871 is a rejected name and, therefore, replaced by Dammarites albens Presl in Sternberg, 1838 herein. The reinterpretation of "Siphonia bovista Gein." from Saxony provides the first proof of Dammarites albens Presl in Sternberg for Germany. [ABSTRACT FROM AUTHOR]

Middle Devonian Pseudosporochnales (Cladoxylopsida) are among the earliest tree-sized plants in the fossil record. We describe here new and spectacular complete specimens of Calamophyton primaevum Kräusel et Weyland from Lindlar (Eifelian, early Mid-Devonian), Germany. These demonstrate for the first time roots, trunk bases, trunks, trunk apices, and crowns of attached digitate branches in organic connection for multiple specimens of one taxon of pseudosporochnaleans from the same horizon. Completely preserved trunks are between 0.8 and 2.0 m long. Middle portions of the trunks demonstrate that the branches were abscised a short distance from the trunk surface, leaving branch bases of consistent length superficially similar to leaves. Such trunks and "leaves" were previously named Duisbergia mirabilis Kräusel et Weyland. Trunk diameter decreases distally in the lower half of the trunk but usually increases distally below the top. Some trunks may have divided dichotomously. The trunk apex is domed and takes up the entire width of the top of the trunk, up to 100 mm in diameter. Overall, the new evidence is not consistent with existing models of pseudosporochnalean growth. The suite of specimens suggests that the upward-growing primary body of the trunk increased in diameter, reaching a mature diameter ~1-2 m from the ground. Lower parts of the plant are therefore likely to have increased in diameter by a process of secondary growth. [ABSTRACT FROM AUTHOR]

Abstract: The largest petrified calamite is reported from the Early Permian fossil forest of Chemnitz, Germany. For the first time a sizable specimen of Arthropitys bistriata permits insights into both the internal anatomical structure and the spatial architecture of the complex branching system. The arboreal woody plant is characterized by a height of more than 10m and at least three orders of axes which formed a large crown. Ontogenetic analyses of the main stem and the various branches of the plant demonstrate that most of the morphological and anatomical features that have been previously recognized as important inter-specific distinctions exhibit a considerable variability. Spheroid to elongate ovoid coprolites have been recognized in the pith cavity of one woody branch ranging from 1.4–2.8×2–5.8mm in diameter. Semi- or undigested fragments of tracheids in the coprolites are identical with those of the parent plant and indicate their histologically pristine nature. According to the coprolite size and fossil records of detritivorous animals, we tentatively suggest that these coprolites were produced by specialized ancient myriapods. Growth rings are densely developed in the peripheral portion of the trunk in particular. As well as climatic cyclicity, they suggest that volcanism-induced environment turbulences become more serious and frequent, and finally buried the whole ecosystem in situ. [Copyright &y& Elsevier]

Abstract: In this study, atmospheric CO2 during the early middle Eocene (~ 47Ma) is reconstructed using fossil plants from the Messel Formation close to Darmstadt, Germany. CO2 concentration is calculated using a mechanistic model of gas exchange which optimizes CO2 uptake by photosynthesis against water vapor loss by transpiration, a strategy that is commonly realized in land plants. Input data for the model are stomatal data (density and pore length), paleoclimate data obtained by two different approaches and biochemical parameters of photosynthesis. Leaves from three taxa belonging to two different families were studied: Laurophyllum lanigeroides, Daphnogene crebrigranosa (both Lauraceae) and Rhodomyrtophyllum sinuatum (Myrtaceae). The results suggest that CO2 was between 853 and 1033ppm during the development of the Messel Formation. Stomatal data therefore indicate a CO2 concentration that was substantially higher than today. The reconstructed range of CO2 concentration is close to data provided by geochemical modeling results and conforms to various data that indicate a warm and ice-free climate during this time interval. [Copyright &y& Elsevier]

Abstract: End-Triassic fluctuations in atmospheric carbon dioxide (CO2) concentration were reconstructed by the use of stomatal frequency analysis on a single plant species: the seedfern Lepidopteris ottonis (Goeppert) Schimper. Stomatal index showed no distinct intra- and interpinnule variation which makes it a suitable proxy for past relative CO2 changes. Records of decreasing stomatal index and density from the bottom to the top of the Rhaetian–Hettangian Wüstenwelsberg section (Bavaria, Germany) indicate rising CO2 levels during the Triassic–Jurassic transition. Additionally, stomatal frequency data of fossil ginkgoalean leaves (Ginkgoites taeniatus (Braun) Harris) suggest a maximum palaeoatmospheric CO2 concentration of 2750ppmv for the latest Triassic. [ABSTRACT FROM AUTHOR]

Abstract: Leaf remains of Ilex L. sect. Ilex known from the Pliocene of Auenheim (Alsace, France) and Frankfurt a. M. - Niederrad (Hesse, Germany) as Ilex aff. cornuta Lindley fossilis Geissert and Ilex aquifolium L. fossilis Engelhardt, respectively, are re-interpreted as representing a new species Ilex geissertii Kvaček, Teodoridis et Wang Qing, sp. nov. Similar leaf fossils occur also in the upper Miocene of the Netherlands (Brunssum), France (Murat), and the Pliocene of Italy (Valdarno Superiore). Although these fossil records were considered either direct ancestors of I. aquifolium L. (Near-East, Europe, N Africa) or allied to I. cornuta Lindley and Paxton (China and Korea), both the mentioned extant species differ in the leaf morphology. Close affinities of I. geissertii to several extant representatives of Ilex subsect. Ilex (= Oxyodontae Loesener nom. illegit.) are indisputable and stress a common origin of this group of the hollies known already from the Oligocene in Europe (Ilex castellii Kvaček et Walther). Several extinct elements of the European late Miocene and Pliocene flora accompanying this new holly (e.g., Ginkgo, Taxodium, Fagus kraeuselii, Parrotia, Craigia, and Trichosanthes) share similar former phyllogeography in having their modern nearest relatives outside Europe. [Copyright &y& Elsevier]

The sedges (family Cyperaceae) are an economically and ecologically important monocot group dating back at least to the Paleocene. While modern genera are mostly unknown before the Oligocene, several extinct taxa are recognized as the earliest sedges. Their affinities have been unclear until now, because they are found as isolated, often abraded fruits or endocarps. Exceptionally preserved sedge fossils from the Middle Eocene of Messel, Germany yield more characters for identification. Fossil cyperacean infructescences with in situ pollen are recognized for the first time and show features of the early-divergent mapanioid sedges. Pollen resembles that of tribe Hypolytreae. Comparisons with extant taxa suggest the closest affinities with Hypolytrum and Mapania. However, the Messel fossils represent a distinct taxon, Volkeria messelensis gen. et sp. nov. Without the additional characters of infructescence and pollen, the Messel fruits would have been placed in the extinct genus Caricoidea, a typical Eocene sedge that was widespread across Eurasia. Similarities of fruit structure suggest that Caricoidea was also a mapanioid sedge. Mapanioid sedges are found today in tropical wet forests and swamps, a distribution suggesting that early sedges occupied a similar habitat, unlike many modern sedges, and were not precursors to open grassland vegetation. [ABSTRACT FROM AUTHOR]

Abstract: To investigate the potential of stable isotopes of Sphagnum peat deposits for palaeoclimate research and to inform sampling strategies, we present results from a study of selected Sphagnum plant constituents. We report a combined stable carbon and oxygen isotope record of cellulose separately extracted from Sphagnum branches and stem sections manually sampled from a ∼4000 year old peat, deposited in a small dry maar crater located in the Westeifel Volcanic Field, Germany. We have determined the species composition of each individual sample of Sphagnum branches to address the sensitivity of the stable isotope records to potential changes in Sphagnum assemblages. The youngest approximately 3000 years old peat section consists of scarcely decomposed Sphagnum plant material. From the bog''s surface to a depth of ∼60 cm the predominant species is Sphagnum magellanicum. Between ∼60 and ∼550 cm the peat predominantly consists of Sphagnum capillifolium var. rubellum. At greater depths the decomposition status increases, species identification is, however, solely achievable if the record under examination consists of moderately decomposed peat. The stable carbon and oxygen isotope values of cellulose from Sphagnum stem sections are significantly lighter than those of the branches. Both isotopic offsets between the different plant compounds exhibit a strong degree of correlation, are statistically highly significant and observable down-core. The stable carbon isotope offset averages to 1.5‰, however, presumably decreases with increasing age of the plant material. In contrast, the averaged oxygen isotope offset of 0.9‰ is consistent in time. Our results imply that if no differentiation into Sphagnum branches and stem sections prior to stable isotope analyses is possible, erroneous interpretations of the isotope records are likely, since down-core changes in the ratio of branches to stem sections in the peat profile are most likely. This also implies that the removal of all non-Sphagnum plants or plant fragments is insufficient to retrieve stable isotope signals from peat deposits exclusively reflecting palaeo-environmental conditions. Even isotopic records from bulk Sphagnum cellulose comprise of two different signals: firstly, an environmental signal based on the plant response to external controls. This signal is, however, masked by a second plant physiological signal originating from the isotopic offset between branches and stem sections. [Copyright &y& Elsevier]

Plant macrofossil remains have been analysed from two raised peat bogs in northern Germany and Denmark. The quantified vegetation reconstructions of each profile were subjected to multivariate analyses to extract records of changing bog surface wetness (BSW), which are interpreted in these rain-fed bogs as being proxy climate signals. Age/depth models were constructed using radiocarbon dates and a number of drier and wetter phases were defined. The records both register cooler/wetter conditions around 2700, 1800 and 1400 cal. yr BP, and at the beginning of the Little Ice Age around AD 1250-1350. These rising bog water tables must have been reflected in poorer conditions for agriculture, and in particular near Dosenmoor where the profile records a catastrophic change to such conditions culminating at 2750-2600 cal. yr BP. [ABSTRACT FROM AUTHOR]

Well-preserved polliniferous flower buds from the Upper Miocene Inden Beds (Hambach lignite, Lower Rhenish Basin, Germany) were studied by scanning electron and transmission electron microscopy techniques. The Craigia bronnii flower buds are in many respects very similar to those of extant Tilioideae (Malvaceae). The in situ pollen strongly resembles fossil Craigia and recent Tilia pollen, respectively. Especially features of the endexine and the foot layer in the apertural areas and the idiomatic reticulum, including the peculiar mode of branching columellae, are highly similar. Amorphous, highly electron-dense substances (pollenkitt) and orbicules, which are both likewise highly similar to those of recent Tilia, are present between and on the pollen grains of the flower buds. There is evidence from staining and sectioning behavior of this amorphous substance that it in fact represents pollenkitt. [ABSTRACT FROM AUTHOR]

• Low reservoir amplitudes in run-of-river hydropower enable extensive grid balancing. • 1 MW of hydropower can facilitate grid integration of up to 11.6 MW of wind or PV. • Potentials for negative balancing services significantly higher than for positive. • Providing balancing services reduces overall energy production. • Nevertheless balancing services can increase the total incomes. The increasing shares of wind energy and photovoltaics in many countries challenge the energy systems in a twofold way. On one hand, there is an increased need for balancing energy in order to compensate abrupt changes in load or power generation. On the other hand, fossil plants being important providers of balancing services are gradually driven out of the system creating a need for renewable substitutes. Due to strict requirements on the upstream water level regime German run-of-river (ROR)-hydropower has until now remained largely unused for providing positive balancing services. However, in this paper we present a novel optimized operation scheme allowing ROR-plants to exactly keep their production schedule and, in addition to that, provide positive and negative balancing services even under these constraints. Our simulations on an exemplary power plant with a very low head show that huge unused balancing power potentials can be expected for ROR-hydropower in Germany enabling a multiplication of fluctuating renewable energy sources. Next to these potentials under current market conditions, this paper elaborates the economic and ecologic aspects of balancing operation. [ABSTRACT FROM AUTHOR]

• The Geiseltal resinites are well-preserved, pre-amber fossil resins of 43–49 Ma age. • Resins have conifer (Taxodium) and angiosperm (Burseraceae, Dipterocarpaceae) origins. • Possible Taxodium resin is enriched in chamaecydins. • Possible angiosperm resins are rich in triterpenediols, amyrins and ursolic acid. • Species and diagenetic pathways from precursors to the products in resins are suggested. • First structural confirmation of 12-hydroxysimonellite by proton NMR spectroscopy. The former lignite pits of the Geiseltal in Saxony-Anhalt, Germany, were an important source of well-preserved Eocene animal and plant fossil remains, including resinites (fossil resins) from different botanical sources. We studied three different types of resinites with distinct morphological characteristics, collected at one of the Geiseltal pits, elucidated their molecular compositions and identified the main biomarker and natural product compounds present. The excellent preservation of molecular markers in the resinites, not yet consolidated to amber despite their middle Eocene age, allowed us to perform chemotaxonomic assignments by correlation with the natural product compositions of extant plant resins. The results showed that the main botanical contributors to the Geiseltal paleoenvironment were conifers of the Cupressaceae family, pointing to the genus Taxodium by the major presence of chamaecydin, ferruginol, 7α- p -cymenylferruginol and taxodione. The compositions found for two other Geiseltal resinite types suggested an angiosperm origin, compatible with the Burseraceae family and the genera Shorea or Hopea of the Dipterocarpaceae as botanical sources. The results support the theory that this Eocene paleobiome was a semitropical swamp and they provide new data for the diagenetic routes of terpenoid natural products. [ABSTRACT FROM AUTHOR]

The Rhaetian flora from Wüstenwelsberg (Franconia, southern Germany) comprises a diverse array of cryptogam plants. Twelve species of lycophytes, sphenophytes and ferns are identified and described by means of macromorphology and in situ spores, when present. The study is part of the ongoing examination of this recently excavated and excellently preserved fossil plant assemblage. In total, two lycophyte taxa (Lepacyclotes and Selaginellites) and one sphenophyte (Equisetites) have been identified. Ferns are represented by eight species in three families; Osmundaceae with one Todites and two Cladophlebis species; Matoniaceae with two Phlebopteris species, and Dipteridaceae with Clathropteris , Dictyophyllum and Thaumatopteris with one species each. Curled fern fronds have been attributed to the fossil-genus Spiropteris. Besides several key Rhaetian taxa, two key taxa for Hettangian floras, Phlebopteris angustiloba and Thaumatopteris brauniana , are present in Wüstenwelsberg, albeit not in large numbers. The comparison of the flora from Wüstenwelsberg with adjacent Rhaetian floras revealed distinct local differences in the respective floras, which are discussed in the light of paleogeography involving dispersal patterns or mechanisms and adaptations of the plants. • Wüstenwelsberg yielded a very diverse and rich Rhaetian cryptogam flora. • Two lycophyte taxa and one sphenophyte species occur. • Eight fern species of three families, Osmundaceae, Matoniaceae, Dipteridaceae, were identified. • Especially Matoniaceae and Dipteridaceae were common. • A comparison with coeval floras evidences distinct local differences. [ABSTRACT FROM AUTHOR]

The Late Palaeozoic fossil record of plant-insect interactions contains few records of oviposition. Here we report the earliest evidence of exophytic oviposition, where eggs are laid directly on the outer surface of plants. The fossil structures consist of small, circular impressions on plant fossils from the late Pennsylvanian (Gzhelian, Stephanian C) of the Saale Basin in Germany. Their interpretation as exophytic insect eggs is supported by the oviposition pattern, their three-dimensional preservation and the undamaged nature of the plant host tissue. The tight arrangement of the eggs in curved arcs suggests a producer with a short abdomen such as roachoids, the ancestral group of the Dictyoptera sensu stricto. A diagnostic feature of roachoids is their long ovipositor, which was well suited for deposition of single eggs in a distinct pattern. • We report the earliest evidence of exophytic insect oviposition on plants • Fossil material comes from the latest Pennsylvanian (Gzhelian, Stephanian C) of the Saale Basin, Germany • The clusters of small circular egg impressions were probably produced by roachoids • Findings improve understanding of Late Palaeozoic insect-plant interactions [ABSTRACT FROM AUTHOR]