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The iron (Fe)-oxide deposits of the Lahn-Dill-type are composed of haematite-quartz and rare siderite-haematite ores. These ores formed as marine chemical sediments on top of volcaniclastic rocks near the Middle to Late Devonian boundary (∼ 380 Ma). As such, their trace element fractionation patterns provide key information on venting style, ocean chemistry, particle-solution interaction, and depositional environment at the time of ore formation. This study combines WDXRF and ICP-MS/OES whole-rock geochemistry with complementary in-situ LA-ICP-MS analysis, and TEM element mapping of ore samples from the Fortuna Mine (Rhenish Massif, Germany). In-situ measurments were conducted on quartz-haematite, haematite, and siderite-haematite microdomains. Bulk major element contents of the ores indicate (volcani)clastic contamination and post-depositional hydrothermal alteration. Microdomain trace element distributions reveal four different trace element signatures, which are related to: (1) syngenetic apatite formation due to sorption of P and REY from seawater; (2) Fe-(oxyhydr)oxide-specific trace element scavenging and fractionation within the seawater column; (3) diagenetic Fe(III) reduction and trace element mobilisation in pore water; and (4) simultaneous deposition of (volcani)clastic material and Fe-(oxyhydr)oxides. These results show that Lahn-Dill-type iron ore formation resulted from mixing of a low-temperature vent fluid with ambient seawater at high seawater to vent fluid ratios. This likely was related to an environment in which diffuse venting dominated over focused venting, and in which quick Fe-particle precipitation led to formation of haematite-quartz ores. Local diagenetic Fe(III) reduction resulted in post-depositional siderite-haematite ore formation during which trace elements were partially remobilised in pore water. [ABSTRACT FROM AUTHOR]

Three collections of clam shrimp from the Lower Devonian (upper lower Emsian) Klerf Formation of Willwerath and Waxweiler in the western Eifel Mountains are herein studied. Four discernible morphotypes are present in the Willwerath assemblage. These morphotypes correspond to the previously described species from this locality: Pseudestheria diensti (Gross), Pseudestheria subcircularis Raymond, and Palaeolimnadiopsis? eifelensis Raymond. The fourth morphotype also closely corresponds to Pseudestheria diensti, but is slightly different in outline. Asmussia willweratica (Novozhilov) is an objective synonym of Pseudestheria subcircularis. In the Willwerath clam shrimp sample, it is difficult to disentangle taphonomic/preservational versus ontogenetic/sexual variation. If taphonomic/preservational causes could be confirmed, all the Willwerath specimens may represent just one taxon and Pseudestheria subcircularis and Palaeolimnadiopsis? eifelensis would be potential subjective synonyms of Pseudestheria diensti. However, we refrain from a formal taxonomic act, which requires a larger number of specimens to be analysed. In addition, we investigated two samples from Waxweiler, which originate from distinct centimetre-thick layers and therefore represent associations. One of these associations comprises two discernible clam shrimp morphotypes. Because of limited preservation of morphological characters, one is here left in open nomenclature as Spinicaudata incertae sedis, whereas the other is recognised as a new species of the family Palaeolimnadiopseidae, Palaeolimnadiopsis frankeorum sp. nov. The second association from Waxweiler comprises at least four, possibly six different clam shrimp taxa. In addition to Pseudestheria diensti, Palaeolimnadiopsis sp., and poorly preserved Asmussia- and Ulugkemia-like specimens, two taxa can be described as new, namely the vertexiid Cornia wasvilrensis sp. nov. and the leaiine Eicheleaia wenndorfi gen. nov. et sp. nov. Altogether, the Klerf Formation at Waxweiler yields a total of at least five (possibly eight) clam shrimp taxa. The palaeoenvironment of these early clam shrimp from the Klerf Formation is interpreted as a non-marine, relatively proximal deltaic setting with no or very minor marine influence, such as a deltaic freshwater pond or lake. The comparatively high diversity of these lower Devonian clam shrimp suggests a considerably earlier origin and cryptic evolution of the group. [ABSTRACT FROM AUTHOR]

The Changning-Menglian suture zone is a critical tectonic belt pivotal to the evolution of the Paleo-Tethys. The Wenquan Formation, characterized as turbidite deposited on the western side of the Changning-Menglian suture zone as well as the eastern edge of the Baoshan Block. Analysis of detrital zircons from the Wenquan Formation reveals two significant age peaks approximately at 440 and 980 Ma, with additional age populations around 600, 780, and 2 500 Ma. The major age peak at about 440 Ma is come from the andesitic-dominant volcanic arc within the Lancang Block and the western Simao Block, corroborated by the presence of andesite fragments in thin section studies. Meanwhile, the zircons that form the secondary age peak at ∼980 Ma and other older age groups probably originate from the Baoshan Block. Deposited on the western side of the Paleo-Tethyan ophiolites, the Wenquan Formation received detrital materials from the continental margin on the opposite side. Thus, the main Paleo-Tethyan Ocean basin was not sufficiently broad enough to cut off the transference of detrital materials. It was a relatively narrow basin in the Early Devonian. [ABSTRACT FROM AUTHOR]

Information about changes to the depositaries for some holotypes of Paleozoic bryozoans from different localities of Russia and Kazakhstan is provided. [ABSTRACT FROM AUTHOR]

The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed, diverse in lithotypes and rich in fossils. It records the crucial processes of continuous subduction and reduction of the Paleo-Asian Ocean in the northern hemisphere and the transformation of the Proto-Tethys Ocean into the Paleo-Tethys Ocean in the southern hemisphere. Thus, it is of great significance for explaining the global paleogeographic evolution, tectonic activities and biodiversity changes during this critical period. The blocks on both sides of the southern Tienshan suture zone and the Longmu Co-Shuanghu-Changning-Menglian suture zone belong to different sedimentary systems and paleobiogeographic realms and regions, showing important tectonic paleogeographic partitioning significance. The two suture zones represent the main branches of the Paleo-Asian Ocean and the Paleo-Tethys Ocean, respectively, and on this basis the Devonian System can be subdivided into three types: the Tienshan type, the Tethys type and the Gondwana type. Based on recent research progress on the Devonian stratigraphy and paleontology in combining provenance analysis and biotic characteristics in the Qinghai-Tibetan Plateau and surrounding areas, this paper aims to establish the latest integrative stratigraphic framework and conduct paleogeographic reconstruction, providing foundation for exploring the geological evolution and dynamic mechanisms of various terranes and blocks in the northern margin of Gondwana. The results indicate that the North Qiangtang, South Qiangtang, Simao, Baoshan and Tengchong terranes, as well as the Himalaya Tethys Zone and the South China Block have affinities with the Indian Block, while the Lhasa Terrane has affinities with the Australian Block, and may be located between the South China and Australian blocks. In the Emsian (Early Devonian), the South China Block separated from the northern margin of Gondwana, a process that was accompanied by the opening of the Jinshajiang-Ailaoshan Ocean. In the Middle Devonian, the mid-oceanic ridge of the Paleo-Tethys Ocean expanded rapidly, corresponding with a global sea-level rise, the widespread development of carbonate platforms and nadir values of Devonian seawater strontium isotopes. By the Late Devonian, the Paleo-Tethys Ocean had reached a considerable size, leading to abundant occurrences of Upper Devonian radiolarian cherts in the Paleo-Tethys suture zones. [ABSTRACT FROM AUTHOR]

The matter of photosymbiosis in Paleozoic corals remains unresolved as it is not possible to directly check for the presence of algal symbionts in fossil corals. However, present-day photosymbiotic corals are characterised by a number of features that can be evaluated in fossil corals as well, such as large, highly integrated colonies, growth banding, and platy growth forms in mesophotic conditions. The present study aims to evaluate these features in heliolitid corals. Heliolitids were relatively highly integrated, compared to other Paleozoic corals and could produce large colonies, over 1 m in diameter. In this study, heliolitid corals from different outcrops from the Silurian (~ 444 to 419 ma) of Gotland (Sweden) were analysed, and additional Devonian (~ 419 to 359 ma) specimens from Belgium, Poland and Morocco, featuring cyclic growth banding, were also included. Overall, over 60% of studied specimens from Lower Visby Formation in Ireviken and over 80% from Eke Formation in Lau Käldu are platy or tabular. Those outcrops represent environments that were mesophotic. Specimens from the shallower Upper Visby Formation in Ygne are dominated by branching forms instead. The apparent light-related skeletal plasticity, high colony integration, growth banding, and the absence of heliolitids in deep water environments implies that some of these corals were most likely photosymbiotic. [ABSTRACT FROM AUTHOR]

On the basis of the mineralogical-petrographic and geochemical study of igneous rocks of intermediate composition of the Pripyat complex of the Late Devonian Pripyat–Dnieper magmatism area, two subphases of the Pripyat magmatism phase have been distinguished: late Fransian (Chernin or Skolodino–Chernin) with potassium specification and early Famennian (Turov–Drozdov (Yelets)) with potassium-sodium specification. For the first time, the U–Pb age of titanite from trachyandesites of the parametric Pribor borehole was estimated for rocks of Pripyat–Dnieper magmatism area at 364 ± 1 Ma. These data confirm the Famennian age of the Yelets subphase of the Pripyat phase of magmatism and make it possible to estimate the duration of the magmatic activity of this structure at least 14 m.y. taking into account the isotope dating of the earliest phases of magmatism in the Pripyat–Dnieper–Donetsk Paleorift Structure as 388 ± 12, 383.3 ± 3.8, 384.7 ± 3.9, and 383.6 ± 4.4 Ma in the Azov Region and 381 ± 2 Ma in the Pripyat–Dnieper magmatism area. [ABSTRACT FROM AUTHOR]

Lithology of the Lower Frasnian (Upper Devonian) sections, including the Zhelon Regional Stage and the Saria Beds of the Sargaevo Regional Stage, exposed in the basin of the Saryanka River, the Latvian Saddle, is described. The complete lithological description of the Sargaevo and Semiluki deposits (Frasnian) in the Gralevo quarry of the Vitebsk Region, Orsha Depression is presented. Photographic images of macro- and micro-dimensional remains of heterostracans, placoderms, acanthodians, sarcopterygians, actinopterygians, as well as scolecodonts and conodonts found in the Lower Frasnian deposits are presented. For the first time, the Sr isotope composition was measured in remains of ichthyofauna from the Zhelon and Sargaevo deposits of Belarus. Paleoichthyological and taphonomic data, lithology and Sr isotope composition of ichthyofauna fragments, depositional environments in the Zhelon and Saria times were clarified, and the distant sections were correlated. The 87Sr/86Sr values in ichthyofauna samples from the Saria Beds in sections of the Latvian Saddle (sections of Kalyuty 5a and 6, Virenka 1) and the Orsha Depression (Gralevo quarry) lie within similar ranges: 0.70825–0.70842 and 0.70837–0.70856, respectively. The 87Sr/86Sr values in ichthyofauna from the Zhelon deposits in the Kalyuty 2 and Obukhovo 1 sections (Latvian Saddle) vary within 0.70898–0.70932 and 0.71065–0.71102, respectively. High 87Sr/86Sr values in the fossil ichthyofauna of both regional stages suggest that the Early Frasnian paleobasin was significantly desalinated, while the salinity in the Saria paleobasin was comparable to the salinity of the modern Baltic Sea. [ABSTRACT FROM AUTHOR]

Dolomitization is one of the most substantial diagenetic reactions in carbonate systems, occurring where calcite (CaCO3) is replaced by dolomite (CaMg(CO3)2) under a wide range of crystallization temperatures and fluids. This approach led to investigating and documenting field characteristics related to the petrography and geochemistry of the Devonian carbonates in the Peshawar basin, Pakistan. Two hundred samples were collected from various types of dolomitization and studied their petrographic properties, while the geochemical compositions were examined using XRD and carbon–oxygen isotope analyses. These analyses were conducted to understand the diagenetic processes, the dolomitization, hydrothermal fluids, and their development. Dolomitized bodies are randomly distributed within the host limestone, which can be observed in the field where outcrops extend north east-south west in the study region from Kali Shilman to Bara Fort and have been changed by hydrothermal fluids and magmatic intrusions. This research aims to understand the origin, diagenetic evolution, and sedimentary features of the dolomites that make up the Khyber Limestone Formation and provide pertinent knowledge for comprehending the dolomitization-processes in the alteration of hydrothermal-related Devonian carbonates within the Khyber Limestone. Field relationships, petrographic studies, and geochemical analyses helped us understand the paragenetic history of carbonate rocks and their relationship to igneous intrusions. The phenomenon of fluid-rock interaction has received significant attention because hot fluids (hydrothermal) alter the composition of the host limestone in contact. Field observations indicate the host limestone to have thick, numerous mafic intrusions. In the study area, host limestone is altered into dolomite and marble due to these igneous intrusions (mafic composition). A petrographic study demonstrated host limestone alteration, resulting in digenetic alteration and metamorphism. The formation of marble as a result of contact metamorphism has also been observed to act as a barrier against the host limestone being altered by dolomitizing fluids. Field observations, hand specimen examinations, and thin-section studies show that the altered carbonate rocks are also exceptionally finely to moderately to coarsely crystalline. Five distinct types of dolomite rock textures are identified and classified as “planar” and “non-planar” dolomite based on the distribution of crystal sizes and the shape of the crystal boundaries. Planer dolomite crystals have straight boundaries and are divided into euhedral Dol-III and subhedral Dol-IV textures. In contrast, non-planar dolomite crystals (Dol-I) have arched, lobate, ridged, obscure, or irregular intercrystalline boundaries. Planar-subhedral dolomite has a unimodal mosaic structure and is subhedral to anhedral shape with straight compromise boundaries and numerous crystal-face junctions, while planar-euhedral dolomite (Dol-III) is composed of fine to coarse dolomite crystals with dense hazy rhombs. The bulk mineralogy was ascertained using XRD studies. Mostly dolomite and calcite were present along with other minerals like putoranite (Cu17(Fe,Ni)18S32), mangano calcite (Ca,Mn)CO3, quartz, and copper, which can be formed when magmatic activity occurs, so because of some copper-bearing fluids, they were deposited. The C and O isotopic variations of ancient ocean water demonstrate the effects of various diagenetic processes resulting from magmatic emplacement, hydrothermal fluids’ impact, and the consequent on the dolomitization of the Khyber Limestone. [ABSTRACT FROM AUTHOR]

A styliolinid limestone is described from a trench northwest of Bad Laasphe in the southwestern Wittgenstein Syncline. All limestones from the trench contained conodonts and representatives of other microfaunal groups. These lower Frasnian assemblages fall in an interval ranging from the Upper falsiovalis to the transitans Zone. Origin and genesis of the styliolinid limestone remain unclear. [ABSTRACT FROM AUTHOR]

Two bryozoan species belonging to the Family Semicosciniidae Morozova, 1987 are described from the Middle Devonian of the Eifel—Bigeyina winteri (Bornemann, 1884) and Loculipora alvearis (Maurer, 1885). The two species are endemic to the Middle Devonian (Eifelian–Givetian) of the Eifel. Morphology and taxonomical assignment of the studied bryozoans are discussed. The Family Fenestraporidae Xia, 2002 is considered to be invalid. [ABSTRACT FROM AUTHOR]

Modern scleractinian corals can display high phenotypic plasticity, which reflects an interplay among various environmental controls, such as sediment input, water hydrodynamics or light intensity. In particular, the latter can strongly influence the morphology of coral species living across broad depth gradients. Light intensity was also a factor shaping the colonies of extinct Palaeozoic tabulate corals (Anthozoa: Tabulata). Based on gradual transitions in morphology observed in corals from the Middle Devonian (Givetian stage, ~ 385 Ma) mesophotic coral ecosystems (MCE) of the Aferdou el Mrakib reef (Anti-Atlas mountains, Morocco) and comparative material originating from different palaeobathymetric and biogeographical settings, we show that Devonian tabulate corals, such as Roseoporella and Alveolites, were characterised by high phenotypic plasticity and the ability to dramatically change their morphology depending on the inferred light conditions. Such a mechanism is similar to that observed in modern scleractinians, e.g. Porites sillimaniana. This recurring morphological theme suggests that Palaeozoic tabulate corals shared many functional characteristics of modern scleractinians. [ABSTRACT FROM AUTHOR]

Miospores with spines that have bifurcate tips and an equatorial flange from the genus Ancyrospora were an important part of the Mid and Late Devonian spore flora. A number of the early species were described from the Arctic regions of both Canada (Nunavut) and the Timan, Russia. The history of the genus Ancyrospora is reviewed, rediagnosed and compared with Hystricosporites and Nikitinsporites two genera that also possess bifurcate tipped spines. Material from Arctic Canada and Russia was investigated to compare the Givetian and Frasnian species of Ancyrospora that were described in early publications by McGregor, Owens, and Naumova. The species Ancyrospora ampulla, A. melvillensis, A. simplex, A. incisa, A. arguta, A. laciniosa and A. polyacantha are illustrated and described using the same terminology including profiles of the bifurcate sculptural elements. Morphological lineages are recognised between the different species and the Ancyrospora melvillensis morphon defined. Comparative range charts are presented from both Arctic Canada and Russia. Many of the taxonomic issues in comparing Canadian and Russian Ancyrospora are resolved. [ABSTRACT FROM AUTHOR]

This paper describes the optimization of a workflow incorporating experimental implementation of information tools into paleopalynological research. It is proposed to streamline the work of expert palynologists by using an intelligent "deep learning" algorithm, utilizing identification resources such as atlases and photographic plates, by developing an adaptive database. [ABSTRACT FROM AUTHOR]

The results of the study of facies confinement of bryozoans in the Emsian sections of the western part of the Altai–Sayan Folded Area are presented. The schemes of vertical and horizontal distribution of bryozoan assemblages in sections of a stratotype locality of the Emsian Stage of the Northeast Salair are shown. The following new species of fenestellids from the Shanda Regional Substage (Emsian Stage; serotinus conodont zone) are described: Fenestella salairica sp. nov., Laxifenestella magnifenestrula sp. nov., Hemitrypa aktaschensis sp. nov., H. cyathiformis sp. nov., and Rarifenestella ornamentum sp. nov. [ABSTRACT FROM AUTHOR]

Slow crustal subsidence nonuniform in time and space occurred in the sedimentary basin of the Moscow Syneclise during 20 Ma in the Late Devonian. On the cool Precambrian lithosphere of the East European Craton, subsidence of this kind could have occurred only due to rock contraction in the lower crust resulting from prograde metamorphism. Crustal subsidence in the Middle and Late Devonian occurred after a long period of stability. This required the influx of mantle fluids into the lithosphere and then into the crust, which catalyzed the metamorphic reaction. The distribution of crustal subsidence was very heterogeneous, and its pattern repeatedly and radically changed over time. This indicates that the influx of deep fluids into the lithosphere was also highly variable, both in time and in space. There is no evidence of any connection between large basement faults and the pattern of the Late Devonian crustal subsidence. Together with a high variability of the subsidence, this suggests that, over the course of several million years, fluids have penetrated into the crust through an undisturbed mantle lithosphere 150 km thick. This indicates that the fluids had specific properties: they were surface-active and wetted grains of crystalline rocks, spreading as thin films into the inter-grain space. Rapid and frequent changes in the influx of deep fluids into the lithosphere rules out their connection with slow large-scale convective currents in the mantle. The slow, but long-term, extended over tens of millions of years, influx of surface-active mantle fluids into the lithosphere is also quite different from the powerful short-term outbursts of fluids from large mantle plumes approaching the lithospheric layer. The occurrence of crustal subsidence and kimberlite magmatism in a number of cratonic areas remote from each other suggests a widespread influx of deep fluids into the lithospheric layer on the continents. [ABSTRACT FROM AUTHOR]

The Devonian to Carboniferous (DC) transition coincided with a green-to-ice house climatic shift, anoxia, disappearance of lower latitude carbonate banks, and turnover from warm-to-cool water carbonate factories. In western Laurentia, the switch to carbonate factories dominated by cool-water biota was contemporaneous with a tectonically driven palaeogeographic change. To investigate this depositional shift and infer the relative impact of climate vs tectonics, a continental-scale sedimentological and geochemical study was conducted on twelve stratigraphic sections of DC strata from western Canada to southern Nevada (USA). The spatial–temporal distribution of microfacies records the turnover from [i] a Famennian lime mud-rich, shallow warm-water carbonate ramp with low sedimentation rates, mesotrophic conditions and tabular geometry to [ii] Tournaisian to Viséan lime mud-depleted and grainstone dominated cool-water carbonate ramp with anomalous high sedimentation rates, oligotrophic conditions and a pronounced slope. Positive excursions of δ18Ocarb (+ 2‰ V-PDB) and δ13Ccarb (+ 4‰ V-PDB) of Lower Mississippian carbonates likely correspond to the first cooling peak of the Carboniferous-Permian icehouse climate, following carbon withdrawal during black shale deposition during the late Famennian and early Tournaisian. However, late Tournaisian return of photozoan elements and their persistence throughout the Viséan suggests that warmer surface water existed, revealing a decoupling of the lower latitude ocean and the atmosphere. Shoaling of the thermocline was likely a result of cold-water upwelling along an open coast, as the Antler orogen no longer provided an oceanic obstruction to the west. This study shows that carbonate platforms are more susceptible to regional changes than global shifts. [ABSTRACT FROM AUTHOR]

The Hagen-Balve Reef is one of the largest Devonian carbonate complexes in the Rhenish Massif exposed in many former or active, economically significant quarries, especially in the Hönne Valley region at its eastern end. The timing and patterns of reef drowning, final extinction, and the middle Frasnian to middle Famennian post-reefal facies history, including details of the global Kellwasser Crisis, were studied based on two boreholes (HON_1101 and B102) and one outcrop at the Beul near Eisborn. More than 100 conodont samples provided a fine biostratigraphic framework and included new forms left in open nomenclature. The ca. upper 80 m of the new Asbeck Member of the Hagen-Balve Formation consists of relatively monotonous lagoonal successions assigned to four microfacies types. The local diversity of reef builders, mostly stromatoporoids, is low. Fenestral microbialites indicate very shallow and rather hostile back-reef settings. Near the Middle/Upper Devonian boundary, the eustatic pulses of the global Frasnes Events led to a significant backstepping of the reef margin, with reef core/outer slope facies overlying lagoonal facies. This flooding drastically reduced the carbonate accumulation rate and enabled the invasion of drowned back-reef areas by open-water organisms, such as polygnathid conodonts. Within this Eisborn Member, five microfacies types and numerous subtypes are distinguished including low-diversity "coral gardens" and a final, top lower Frasnian parabiostrome dominated by tabulate and colonial rugose corals. There was no cap stage ("Iberg Facies"). Two phases of the Basal Frasnes Event are marked by dark, organic rich limestones with subordinate reef builders. Based on conodont fauna from overlying nodular limestones of the new, (hemi-)pelagic Beul Formation, the final Hönne Valley reef extinction was caused by the eustatic Middlesex Event at the lower/middle Frasnian boundary. Within the Beul Formation, eight subphotic submarine rise microfacies types are distinguished. After a lower middle Frasnian phase of extreme condensation, rich conodont faunas enable the recognition of most upper Frasnian to middle Famennian zones. The global semichatovae Event led to a regionally unique intercalation by four phases of organic-rich, laminated black shales and intervening thin limestones in core HON_1101. The Lower Kellwasser Event is represented in HON_1101 by atypical, moderately Corg-rich, recrystallized, peloidal ostracod-mollusk pack-grainstones. The Upper Kellwasser level begins with an ostracod bloom, followed either by recrystallized mollusk wacke-packstones (HON_1101) or laminated, argillaceous mudstones (B102). The first indicates a rarely documented shallow subphotic, better oxygenated setting than typical Upper Kellwasser facies. As elsewhere, the top-Frasnian conodont extinction was severe. The lower/middle Famennian carbonate microfacies of the Beul Formation is relatively monotonous and typical for an oxic, pelagic submarine rise. The youngest recorded nodular limestones fall in the Palmatolepis marginifera utahensis Zone. Regionally uniform lydites of the Hardt Formation show that the local palaeotopography was levelled before the base of the Viséan. The Hönne Valley case study and comparisons with western parts of the Hagen-Balve Reef and other Rhenish reefs underline the significance of Givetian to middle Frasnian eustatic and anoxic events as causes for reef extinctions. [ABSTRACT FROM AUTHOR]

The cosmopolitan genus Gondwanaspis is one of two post-Taghanic (late Givetian to Frasnian) odontopleurid genera and the only genus of the Odontopleurida surviving the Lower Kellwasser Event, finally disappearing at the Upper Kellwasser Event. Although it is known from the Frasnian of Australia, Germany, France, Morocco, and Russia, findings of the genus are comparatively rare. Here we present Gondwanaspis eisbornensis n. sp. from the probable lower Frasnian of the Beul section near Eisborn (northern Sauerland) and Gondwanaspis schloesseri n. sp. from possibly top-Givetian strata of the Hofermühle South Quarry of the Bergisches Land (Velbert Anticline), both in the northern Rhenish Massif. Gondwanaspis schloesseri n. sp. represents one of the few species of which both the cephalon and pygidium are known, while the holotype of G. eisbornensis n. sp. is one of the largest known specimens within the genus. [ABSTRACT FROM AUTHOR]

The genus Ontaria Clarke, 1904 includes a group of small, almost circular bivalves that occur abundantly in the Mid- and Late Devonian pelagic facies. These bivalves are characterised by their straight hinge line, small and, central beak, as well as commarginal rugae (if present). Based on an extensive review of type material and additional samples as well as a comprehensive literature review, this study identifies three valid species Ontaria suborbicularis Hall, Ontaria concentrica von Buch, and Ontaria iniquistriata Beushausen. Thirteen Ontaria species are either not valid or have been synonymised, and three species that were previously included in Ontaria do not belong to this genus. Representatives of Ontaria first occur in the late Eifelian and become abundant in the Frasnian and Famennian. Ontaria last occurs in the late Famennian before the Devonian/Carboniferous boundary. This genus has been identified as a representative of the family Cardiolidae previously reported only from the Silurian, making Ontaria the first report of a Devonian cardiolid taxon. Ontaria inhabited low-energy, generally well-oxygenated, off-shore environments. The overall shell morphology, small size, and the presence of a small siphon supports the idea that Ontaria lived semi-infaunal in/on muddy substrates. [ABSTRACT FROM AUTHOR]

The sedimentary basin of the Moscow syneclise is located in the central part of the East European craton. It is characterized by detailed drilling coverage and an extremely high degree of geological knowledge. During the Devonian the basin was exposed to laterally non-uniform crustal subsidence after a long period of erosion. Considering the large thickness of the ancient lithosphere, this subsidence regime could only take place here in connection with rock contraction in the lower part of the crust as a result of prograde metamorphism catalyzed by the infiltration of mantle fluids. Their inflow into the lithosphere of the East European craton is evidenced by the wide occurrence of basite and kimberlite magmatism during the Devonian. The lateral distribution of subsidence throughout the syneclise changed significantly over periods of several million years. This indicates the corresponding changes in the rate of inflow of the deep fluids into the ancient lithosphere and their high surface activity. This property of the fluids enabled their rapid infiltration into the mantle lithosphere and inflow into the crust over the entire syneclise. The long-term inflow of the deep fluids into the continental lithosphere, which frequently changed in time and space, is a hitherto unknown phenomenon not related to large-scale convection in the mantle or to the rise of large plumes. It could have been the cause of the formation of many intraplate sedimentary basins on the continents. [ABSTRACT FROM AUTHOR]

Brief information on the recently described Parmastega and newly discovered unpublished tetrapod material from the Devonian sequence of Timan is given. The significance of these discoveries is discussed. [ABSTRACT FROM AUTHOR]

Changes in the nearshore pelagic ecosystems at the Devonian–Carboniferous boundary are considered. These changes are reconstructed based on conodont ecogeochemistry, carbon isotopic composition of marine carbonates, and abundance of the unilocular foraminifer Bisphaera. [ABSTRACT FROM AUTHOR]

This study describes the results of a detailed study (morphology, XRD, Mössbauer and FTIR- spectroscopies, SEM-EDS) of paleosol (PS) developed at the surface of Pre-Cambrian weathering crust of ferruginous quartzite (Kursk Magnetic Anomaly Region). The age of soil formation is estimated as pre-Eifelian. Being developed from pyrite bearing metamorphic rock, the PS includes the characteristics of several pedogenic units, mostly Lithosol and acid sulphate soil. Its specific feature is intensive pedogenesis within the rock at a depth of 10–15 cm, and negligible at the surface. The PS was developed under low monotypic vegetation cover. The sub-micromorphology of plant fragments shows that they belong to either primitive Lycopodiophyta or to Propteridophyta. The similarity between the micromorphology of fragments of surface and subsurface parts of plants shows the development of primitive roots. Azonality of soil characteristics makes paleoclimate reconstructions difficult. For instance, evidence of deep mineral weathering, such as quartz and hematite dissolution, the formation of kaolinite, and amorphous Si, Al, Fe mineral crusts development may reflect climate humidity or aggressive weathering caused by sulfide oxidation. The newly formed gypsum could be a product of deep pyrite oxidation rather than accumulation due to climate aridity. However, its preservation suggests non-humid (semi-arid), rather than humid environments. [ABSTRACT FROM AUTHOR]

Two new mitrate stylophorans are described from the upper part of the Santa Rosa Formation (Lochkovian) in the Central Subandean Zone of Bolivia and from the Jupiter Formation (Cybèle Member, late Llandovery) of Anticosti Island (Canada). Both stylophorans are identified as allanicytidiine anomalocystitids. The new Bolivian mitrate, Perikefalea racheboeufi gen. and sp. nov. is characterized by a strongly reduced number of plates (five) on its upper thecal surface and a strong spike on its posterior median marginal. The morphology of P. racheboeufi suggests relatively strong affinities with Occultocystis, from the Lower Devonian Talacasto Formation of Argentina. Although incompletely preserved, the Anticosti mitrate, Perikefalea? cybeleae sp. nov., represents the first stylophoran described in the Silurian of North America and the first report of post-Ordovician Allanicytidiinae outside of (peri) Gondwanan regions. Skeletal homologies in mitrates (marginals, infracentrals, posterior spines, adorals, supracentrals) are reevaluated, so as to describe the plate pattern of Perikefalea. This revision was prompted by new fossil evidence from the Furongian–Tremadocian interval suggesting that (1) mitrates derive from "Phyllocystis" jingxiensis-like cornutes with wide marginals, a posteriorly open marginal frame (loss of M5 and ), a zygal plate in central position, and confluent, sutured M3 and G; (2) anomalocystitids derive from Mitrocystites-like mitrocystitidans by modification of two marginals (digital and glossal) into posterior spines. Two distinct terminologies are tentatively proposed for supracentrals in Allanicytidiinae and Anomalocystitinae, because the highly standardized plate patterns of their Siluro-Devonian representatives were possibly acquired independently in the two clades. [ABSTRACT FROM AUTHOR]

Metagabbroid garnet amphibolite formed after high-pressure granulite with an estimated P–T peak of 12–16 kbar at 700–790°C occurs at the sole of the Kempirsai ophiolite allochthon (Southern Urals). Garnet amphibolite includes high-Fe varieties with the assemblages of garnet and relics of pyroxene, as well as high-alumina rocks composed of garnet, pyroxene, corundum, and sapphirine. The Ediacaran and Early–Middle Palaeozoic sequences underlying the allochthon were metamorphosed under the conditions of amphibolite facies. Our studies were aimed at estimation of the peak metamorphic age of garnet amphibolite. The mean 206Pb/238U (SIMS, SHRIMP II) age obtained for the zircons from garnet amphibolite is 392 ± 4 Ma. The estimated age characterizes the timing of metamorphism related to mantle magmatism accompanying obduction. [ABSTRACT FROM AUTHOR]

For earth scientists, to examine how life forms interact with their environment is of key importance to understand evolutionary linkages and adaptations within the biosphere. The Devonian Period experienced many changes of marine and terrestrial ecosystems, most notably the proliferation of vascular plants that accelerated terrestrial weathering and nutrient flux to the oceans and resulted in globally extensive deposition of organic-matter-rich mudstones. In geologic history, such strata appear to be linked to global rise of sea level, greenhouse climate with elevated atmospheric pCO2, active volcanism, and extinction events. A concerted effort in multiple fields is aimed at understanding the history of oxidation states, modes of organic-matter preservation, and how paleoredox conditions are influenced by local and global drivers (e.g., sea level, tectonics, volcanism). In this study, we document the discovery and unique preservational style of agrichnia (graphoglyptid) traces in Middle–Late Devonian organic-rich shales from three different basins across North America. On slabbed core surfaces the remains of these burrows appear as inconspicuous discontinuous, bedding parallel pyritic streaks, but X-ray computed tomography (CT) scans show bedding parallel pyritized polygonal structures that are interpreted as graphoglyptid burrows. Agrichnia are generally attributed to trace-makers capable of constructing interlaced branching structures to harvest microbial consortia in oxygen-stressed settings, and their discovery in black shales provides new perspectives for interpreting the benthic habitability of organic-rich depositional settings. [ABSTRACT FROM AUTHOR]

A massive occurrence of microbial carbonates, including abundant sponge remains, within the Devonian Elbingerode Reef Complex was likely deposited in a former cavity of the fore-reef slope during the early Frasnian. It is suggested that the formation of microbial carbonate was to a large part favored by the activity of heterotrophic, i.e., sulfate-reducing bacteria, in analogy to Quaternary coral reef microbialites. The Elbingerode Reef Complex is an example of an oceanic or Darwinian barrier reef system. In modern barrier reef settings, microbialite formation is commonly further facilitated by weathering products from the central volcanic islands. The Devonian microbialites of the Elbingerode Reef Complex occur in the form of reticulate and laminated frameworks. Reticulate framework is rich in hexactinellid glass sponges, the tissue decay of which led to the formation of abundant micrite as well as peloidal and stromatactis textures. Supposed calcimicrobes such as Angusticellularia (formerly Angulocellularia) and Frutexites, also known from cryptic habitats, were part of the microbial association. The microbial degradation of sponge tissue likely also contributed to the laminated framework accretion as evidenced by the occurrence of remains of so-called "keratose" demosponges. Further typical textures in the microbialite of the Elbingerode Reef Complex include zebra limestone, i.e., the more or less regular intercalation of microbial carbonate and cement. Elevated concentrations of magnesium in the microbialite as compared to the surrounding metazoan (stromatoporoid-coral) reef limestone suggests that the microbialite of the Elbingerode Reef Complex was initially rich in high-magnesium calcite, which would be yet another parallel to modern, cryptic coral reef microbial carbonates. Deposition and accretion of the microbialite largely occurred in oxygenated seawater with suboxic episodes as indicated by the trace element (REE + Y) data. [ABSTRACT FROM AUTHOR]

Abstract—In order to determine the Earth's magnetic field intensity in the Devonian, a collection of rocks of the Baymak-Buribay formation of the Buribay volcanic complex in the West Magnitogorsk Zone—Southern Urals, Khvorostyanka section, has been studied. The complex dates back to the Late Emsian of the Early Devonian (D1e2, 408–393 Ma), based on the conodont fauna. A full set of experiments to study the magnetic and thermomagnetic properties of rocks and to assess the domain structure of magnetic grains have been performed; micromagnetic and X-ray studies have been carried out. It is shown that the carriers of the characteristic component of natural magnetization are single-domain and small pseudo-single-domain grains. The (Banc) paleointensity has been determined by the Thellier-Coe method and the Wilson express method. Ultra-low Banc values = (2.01–7.07) μT have been obtained in 8 samples (24 duplicates) from two sites. The average values of the virtual dipole moment (VDM) for both sites are close to each other and equal to ≈1×1022 Am2, which is almost an order of magnitude less than its current value of 8 ×1022 Am2. The new Banc determinations confirm the hypothesis that there was a period of very weak field in the Devonian, which again raises questions about the time of the Earth's solid core formation and the geometry of the geomagnetic field during periods of a very weak field intensity. The new Banc determinations are consistent with the already obtained data on paleointensity in the Devonian, indicating a high probability that there was a long period of a weak field at this time, the intensity of which is close to the intensity of the nondipole components of the current field. This fact raises the question about the actual geometry of the field at that time—was it dipole or multipole? [ABSTRACT FROM AUTHOR]

The Late Devonian section of the small Stolb Island in the Lena River delta is famous for the mass disappearance of a considerable number of taxa in its lower part, which may indicate the Upper Kellwasser global biotic catastrophe. Our task was to create a rock magnetic reference for this section and to search for "magnetic traces" of the inferred biotic event. The resulting rock magnetic "portrait" testifies to a stable sedimentation mode and excludes the influence of regional tectonic factors that could contribute to an abrupt change in the habitat conditions in the basin. At the same time, the paleomagnetic record does not correspond to the one expected one for these coordinates of Siberia and points to the probable anomalous nature of the geomagnetic field, against which the Upper Kellwasser mass extinction took place. [ABSTRACT FROM AUTHOR]

We report an essential result of offshore exploration, that is, the discovery of a new oil- bearing region in the eastern part of the Pechora Sea shelf. Large oil fields, that is, the Prirazlomnoye, Varandey-more, Medyn-more, and Dolginskoye fields, have been discovered. The explored reserves and resources of hydrocarbons suggest that a new oil-producing region will be formed on the Pechora Sea shelf in the near future. According to the State Balance, the total initial raw oil resources in the Pechora Sea amount to 3273.2 million tons. The main purpose of our work is to draw attention to the problem of accelerating the research of the promising objects on the Pechora Sea shelf and to the additional exploration of the discovered deposits in the Ordovician–Lower Frasnian oil and gas megacomplex in the Varandey–Adzva structural zone (VASZ). The disproportion between the plans for the development of the fuel and energy complex, its resource availability, and the rate of replenishment of the mineral resource base of hydrocarbons on the Pechora Sea shelf may cause serious problems for the energy safety of the country. The further development of the large oil production cluster on the shelf of the Pechora Sea is primarily associated with the prospecting and development of hydrocarbon resources of the relatively deep-lying oil and gas bearing predominantly carbonate Ordovician–Lower Frasnian megacomplex (MC). This complex occurs on the shelf of VASZ and adjacent areas, especially at the Prirazlomnoye and Medyn-more fields. [ABSTRACT FROM AUTHOR]

A relatively complete conodont record from Famennian to the Mississippian/Pennsylvanian boundary was investigated in the Anarak section, Central Iran. The studied interval belongs to the Bahram, Shishtu, Ghaleh and Absheni formations. The Famennian part of the section (Bahram Formation) ranges from the Palmatolepis triangularis Zone into the Bispathodus ultimus Zone. Not all conodont zones could be defined due to the lack of indicative species. Furthermore, it seems likely that a hiatus occurs around the Devonian/Carboniferous (D/C) boundary (most probably from the Siphonodella praesulcata to the ?Siphonodella sulcata–early Siphonodella crenulata conodont zones) based on the lack of stratigraphically important conodonts as well as on sedimentological criteria. The lack of representative siphonodellids and protognathodids at the base of the Mississippian prevents detailed stratigraphic position of the D/C boundary. Lower Carboniferous (Mississippian) rocks are characterized by red nodular limestone which is unique in comparison with other studied sections of the same age in Central Iran. Within the studied section, we could define the Mississippian/Pennsylvanian boundary. The mid-Carboniferous boundary was defined by the occurrence of Declinognathus noduliferus s.l. Conodont biofacies changes (Mississippian genera Gnathodus and Lochriea have been replaced by Pennsylvanian genera Declinognathus and Idiognathodus) are recognized in this section as well. [ABSTRACT FROM AUTHOR]

The early Famennian phacopid trilobites Feistops mongoliensis gen. nov. sp. nov., Feistops khovdensis gen. nov. sp. nov., ?Feistops sp. A, and ?Houseops olonbulagensis sp. nov. are recorded and illustrated from the western Mongolia Hushoot Shiveetiin gol section from the Baruunhuurai Terrane of the Central Asian Orogenic Belt (CAOB). In this section, exposing large parts of cyclic Famennian shallow-water siliciclastic shelf deposits, Feistops mongoliensis gen. nov. sp. nov., Feistops khovdensis gen. nov. sp. nov., ?Feistops sp. A, and ?Houseops olonbulagensis sp. nov. are the first known and described representatives of trilobites from Late Devonian deposits of western Mongolia. Their affinities with known other sighted species of the same age are discussed. [ABSTRACT FROM AUTHOR]

Herein we report on the most abundant and diverse fauna of Palaeozoic crinoids and blastoids collected from Mongolia to date. The fauna is from the Late Devonian (Famennian) Samnuuruul Formation in western Mongolia. The fauna consists of two genera of blastoids and twelve genera of crinoids—four genera of camerates, three genera of flexibles, one disparid genus, and four genera of cladids. The crinoids and blastoids were living on an active island arc complex in the Central Asian Orogenic Belt (CAOB) in a high physical stress environment with frequent and often voluminous pyroclastic eruptions. The Mongolian fauna is similar to coeval faunas collected from the Hongguleleng Formation in western China and supports the hypothesis that the CAOB was a biodiversity hotspot for Famennian echinoderms and a precursor to the very successful echinoderm communities that dominated Mississippian shallow-marine ecosystems globally. Three new taxa are described. Mongoliacrinus minjini, new genus and species, is the oldest member of the Acrocrinidae, previously known from the Mississippian and Pennsylvanian and the first occurrence of the family outside North America. Eutaxocrinus ariunai and Eutaxocrinus sersmaai are new species of the flexible crinoid Eutaxocrinus, a genus with a widespread distribution during the Early and Middle Devonian, which survived into the Lower Mississippian. It is restricted to the CAOB in the Late Devonian. [ABSTRACT FROM AUTHOR]

The eastern Anti-Atlas of Morocco represents one of the most completely exposed and perfectly documented biostratigraphic records of the entire Devonian worldwide. Paleogeographically it is clearly differentiated into shallow basins, pelagic platforms, and land areas which are newly defined and illustrated, one from the top of the Middle Devonian, the other from the middle Famennian as two of the most characteristic intervals. The dominant paleogeographic feature is the T-shaped Tafilalt Platform which, in spite of common unconformities and hiatuses, provides the best-documented biostratigraphic record through the entire Devonian. The westernmost termination of this platform was emerged during most of the Devonian (and locally even earlier) and became only flooded again by the Tournaisian transgression. In contrast to previous interpretations, this area is considered as autochthonous. In the Mader Basin subsidence was up to one hundred times higher with respect to the adjacent platforms, but water depth during the Middle Devonian to middle Famennian interval generally remained above storm-wave base. Devonian rocks are only patchily and incompletely preserved on the Mader Platform, which can be considered as an intermittently flooded peninsula connected to the Lower Paleozoic farther west. The major paleotectonic element of the entire area is the Great Anti-Atlas Fault, a sinistral strike-slip fault, which sharply confines the above-mentioned realms in the south. [ABSTRACT FROM AUTHOR]

The Devonian strata of the Tagil Megazone were studied on the eastern slope of the Northern Urals. It was established that Devonian sedimentary-volcanogenic formations were formed within three paleoenvironments: the shelf zone of the extinct Silurian island arc, the intra-arc trough, and the active island arc. The volcanics are similar in composition to the modern island-arc rocks. This zoning was disrupted during the Givetian owing to the formation of grabens and the eruption of basalts with intraplate geochemical characteristics. The volcanic island-arc activity was renewed in the late Givetian and the early Frasnian. The evolution of the island arc was completed in the late Frasnian–early Famennian owing to its accretion to the continental margin. [ABSTRACT FROM AUTHOR]

Studies of fossil bacteria show that mineral formation affected by or involving bacteria has occurred everywhere on Earth since the emergence of bacteria. Homogeneity of rocks and rock formations in the Precambrian and Devonian indicate that similar conditions in the Archean, Proterozoic, and Devonian, during the formation of the rocks studied. [ABSTRACT FROM AUTHOR]

A new species, Phoebodus curvatus from the Middle and Upper Devonian of the Middle and South Urals is described. The teeth of the new species differ from the teeth of other Phoebodus species in the very long lateral cusps curved lingually, and narrow labio-basal projection protruding beyond the labial edge. The distribution of all known Phoebodus species is analyzed. The ranges of five previously established phoebodontid zones are revised and emended. Two species radiations are recorded in the Late Frasnian and the Middle-Late Famennian. [ABSTRACT FROM AUTHOR]

Devonian cutinitic liptobiolith is a special cuticle-rich coal formed during the early stage of land plant evolution. In China, this special coal has previously only been reported in the Yangtze area, with the Luquan Devonian cutinitic liptobiolith of Yunnan Province being the most well-known. Recently, this type of coal was first discovered in the Bulonggoer Sag, to the northwest of the Junggar Basin, NW Xinjiang. Its geological age is regarded as the Givetian period of the late Middle Devonian, which is equivalent to the age of the Luquan Devonian coal. The cutinitic liptobiolith from NW Xinjiang has a distinct sheet-like texture resembling a stack of paper or leaf sheets in appearance, and so it is commonly called "paper coal" or "leaf coal". Ribbon-like cutinite (thick-walled type) is the most abundant maceral in the coal (>60% and up to 80%, on a mineral-free basis), followed by ribbon-like collotelinite. The NW Xinjiang and Luquan cutinitic liptobioliths share similar maceral compositions; while their coal-forming plants and depositional conditions are distinct. The NW Xinjiang cutinitic liptobiolith was deposited in a regional fluvial or flood plain condition, with lycopsids as the dominant coal-forming plants. In contrast, the Luquan cutinitic liptobiolith formed in a coastal-lagoon environment, with primitive ferns as the predominant coal-forming plants, followed by lycopsids. The saturated fractions of the NW Xinjiang and Luquan liptobioliths are mainly composed of tetracyclic diterpanes. However, the tetracyclic diterpane compositions in the NW Xinjiang cutinitic liptobiolith are distinct from those in the Luquan Devonian coal: The former is dominated by atisanes and the latter is mainly composed of phyllocladanes. Different coal-forming plants may have contributed to the distinct tetracyclic diterpane compositions. [ABSTRACT FROM AUTHOR]

The enigmatic microfossil Triskelia scotlandica from the Lower Devonian Rhynie chert is an acritarch-like, usually spheroidal to ovoid vesicle with a surface ornamentation comprised of isolated triradiate and meandering, high membranous ridges. The form has been formally described based on dispersed specimens preserved inside the remains of a land plant axis, and interpreted as the resting stage of a microscopic alga. Unusual microbial coatings on land plant axes from the Rhynie chert have recently yielded > 300 additional specimens of T. scotlandica, many of which occur in situ in prominent swellings of fungal hyphae. This discovery is a strong evidence that T. scotlandica is not algal, but rather fungal or fungus-like in nature. The swellings might be oogonia of a representative of the Oomycota (e.g., Saprolegniales), and T. scotlandica accordingly an ornamented oospore. However, specimens with a discharge tube suggest that T. scotlandica is more likely a zoosporangium or resting spore stage of an endoparasite, perhaps with affinities to the holocarpic Oomycota (e.g., Olpidiopsis), Cryptomycota (e.g., Rozella), or zoosporic fungi (e.g., Olpidium), in which case the hyphal swellings would be either dilatations resulting from the expansion of the parasite inside, or a host response (hypertrophy). The affinity of T. scotlandica remains unresolved, due in part to the uncertain diagnostic value of the surface ornamentation, and because no other stages of the life history of this organism are known. Nevertheless, the new specimens expand our knowledge of the microbial interactions that existed in early terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

A new eurypterid specimen from the Early Devonian of Willwerath is described. The character combination seen in this fossil suggests that it is probably an adelophthalmoid eurypterid morphologically not unlike the co-occurring Parahughmilleria. However, it differs in many respects and a new genus and species, Pruemopterus salgadoi gen. et sp. nov., is proposed to accommodate this fossil. This finding underpins the importance of Willwerath as a eurypterid Lagerstätte with respect to exceptional preservation and high diversity. [ABSTRACT FROM AUTHOR]

Septal crowding is widely known as a sign of maturity in conchs of ammonoids and nautiloids. However, reduced septal spacing may also occur as a consequence of adverse ecological conditions. Here, we address the question how septal spacing varied through ontogeny in representatives of some of the major clades of Devonian and Carboniferous ammonoids. We found that the degree of ontogenetic variation is similar between clades and that variation is only weakly linked with conch form. The results show that septal crowding alone is insufficient to identify adulthood in ammonoids; intermediate septal crowding is a common phenomenon and occurs in various growth stages. Changes in septal distances during ontogeny were, in addition to adulthood of the individuals, a passive reaction likely caused by fluctuating environmental conditions. [ABSTRACT FROM AUTHOR]

Trace fossils occur in several strata of the Devonian and Carboniferous of the eastern Anti-Atlas, but they are still poorly documented. Here, we describe a fossil swimming trace from strata overlying the Hangenberg Black Shale (correlation largely based on lithostratigraphy; Postclymenia ammonoid genozone, ca. 370 Ma old). We discuss the systematic position of the tracemaker and its body size. This ichnofossil is important for three main reasons: (1) it is considered here to be the first record of Undichna from the Devonian of Gondwana, as far as we know; (2) it is the oldest record of vertebrate trace fossils from Africa; (3) it provides a unique window into the behaviour of Late Devonian fishes for which body-fossils cannot provide direct evidence. Further, we put this discovery into the macroecological context of the palaeoenvironment following the Late Devonian Hangenberg biodiversity crisis. [ABSTRACT FROM AUTHOR]

The main trends in the morphological evolution of bryozoans at the Devonian-Carboniferous boundary were established when studying the Late Devonian–Early Mississippian bryozoans of Eurasia. The diversity of vertical colonies increased from Early Famennian to Late Tournaisian. An increase in their strength occurred by growth of the exozonal skeleton due to the growth of vesicular tissue in cystoporates, thickening of the autozooidal walls in trepostomates, complication of polymorphism in cryptostomates, and thickening of the branches in fenestrates. The most rapid evolutionary changes were observed in rhabdomesine bryozoans of the order Cryptostomata, expressed in the change of the spiral arrangement of autozooids to complex one and a high diversity of heterozooids and styles. The development of keels, nodes, superstructures, acanthostyles, and spines in bryozoans provide protection from predators. [ABSTRACT FROM AUTHOR]

The Jebel Ardouz massif west of Marrakech (M’zoudia region) is one of a few Paleozoic outcrops that arises from the Pliocene-Quaternary Houaz plain (Kebir, Lahalima, Alamma, and Ferjane). Locally, the first tree hills capped by the Devonian limestones have been exploited by the Asmar cement plant since 1974. The Koudiat Ferjane, not yet exploited, consists of undeformed and unmetamorphosed Devonian rocks. The exposed limestones have been sampled in order to determine their conodont microfauna. The samples delivered the best-preserved conodonts of the Jebilet region and attest the only reef structure of the Middle Devonian (Givetian) platform in the area, witnessing the expansion of the Prototethys between Gondwana and Laurussia. For the numerous sedimentological, paleontological, and paleoenvironmental features, the easily accessible Koudiat Ferjane represents a unique geological heritage site. It deserves protection for geotourism and education, both for scientific purposes and for the general public, and must therefore be preserved and protected from the upcoming destruction. [ABSTRACT FROM AUTHOR]

This study provides a description of the Devonian radiolarian associations of northern Eurasia and discusses their role in the evolution of Earth's biosphere. It contributes to evolutionary studies of the Earth and its organic world by reconstructing the diversity dynamics of the Devonian radiolarian biota and the chorology of its components, at the same time revealing the biostratigraphic and paleoecological potential of radiolarians. The taxonomic composition and characteristics of the dominant morphotypes in radiolarian communities are indicators of environmental conditions. Associations of radiolarians vary significantly between different, even neighboring, water areas, so they can be considered as ecozones. Data on the structure of associations of radiolarians at the level of taxa of higher rank (classes) are a kind of "certificate" or "passport" of ecozones of individual paleobasins. Radiolarian ecozones replace each other in time, which allows their use for biostratigraphy. The results of the new and revisional studies of the Devonian radiolarians from 15 regions of northern Eurasia enabled a refined and detailed radiolarian scale of the Devonian system and description of 39 Devonian radiolarian ecozones, 24 of which are described for the first time: 17 ecozones are recognized based on the literature data, while seven ecozones are based on analysis of new data. Of 39 ecozones, 33 are dated based on conodont data, and six are dated using the co-occurring foraminifers, ostracodes, and/or ammonoids. General patterns in the evolution of Devonian radiolarians of northern Eurasia are considered and discussed. Spherical porous Sphaerellaria distinctly dominated in the Devonian. A clear trend towards an eastward increase in the relative abundance of spongy and latticed morphotypes of Spumellaria is shown. Spiny Aculearia of the orders Fasciculata and Triangulata are found to have been widespread. The early evolution of the bilaterally symmetrical Albaillellata is recorded. It is shown that in the Famennian, radiolarians with a pylome, Popofskyellidae and Archocyrtiinae, were common, while the genus Caspiaza first appeared at that time. The habitats and the distribution of the discoidal and ellipsoidal radiolarian morphotypes are analyzed in space and time. The dominance of these morphotypes can be used as an indicator of shallow water settings and a marker of transgression and regression boundaries in the paleobasin. A model of cyclic deposition of Domanik-type rocks in an anoxic basin is proposed, and the ecology of radiolarians in the anoxic environments of the Middle Frasnian Domanik Paleosea is analyzed. The predominance of the spiny morphotypes over spherical radiolarians is proposed as a paleoclimatic coefficient indicating cooling of the seawater in a paleobasin. Devonian radiolarians are represented by indigenous species and migrant species: (1) the value of the settled index exceeds that of the migration index by 3–5 times, (2) radiolarians occupied new ecological niches by emigration of evolutionarily young species representing genera with one–two species in total. Four radiolarian migration episodes are established in the Famennian basins of Laurussia. The monograph is intended for widespread use in paleontology, biostratigraphy, paleoecology, paleobiogeography and for university courses. [ABSTRACT FROM AUTHOR]

The recent demonstrations that widespread mid-Palaeozoic Prototaxites and other nematophytes had fungal affinities indicate that terrestrial fungi were important elements in carbon cycling in the Early Devonian. Here, we provide evidence for their participation in the recycling of nutrients by early terrestrial invertebrates. Evidence is in the form of coprolites, both those associated with nematophytes or containing their fragmentary remains. Cylindrical coprolites consistently associated with fungal mats are placed in a new ichnospecies, Bacillafaex myceliorum. Their contents are granular to amorphous, suggestive of complete digestion of the ingested hyphae, with the inference of possession of chitinases in the digestive tracts of the consumers. A further single example comprises a cluster of cylindrical bodies attached to the lower surface of a Nematothallus fragment. Here, homogenisation was less complete, with traces of hyphae remaining. Terrestrial animal fossils have not been found at the locality, but scorpions, pseudoscorpions, Opiliones, mites, centipedes (carnivores) and millipedes, and Collembola (detritivores) have been recorded from the slightly younger Rhynie cherts. Studies of fungivory in extant arthropods have concentrated on Collembola and, to a lesser extent, mites, but their faecal pellets are much smaller than the fossil examples. Millipedes, based on body size and faeces of extant forms, are considered more realistic producers, but little is known about fungal feeding in these animals. Regardless of the affinities of the producers, the diversity in morphology, sizes, aggregations, and composition of nematophyte-containing examples suggests that fungivory was an important component of carbon cycling in early terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Twenty types of conodont element pathology are considered, and the examples of Abrasio, Accessio, Caudatio, Depressio, Diminutio, Duplicatio, Fusio, Impressio, Jugatio, Occlusio, and Suppressio pathologies identified in the Devonian of the Voronezh Anteclise are illustrated in detail. All pathological phenomena are assigned to five genetic groups: (1) mechanical damage to hard tissue; (2) disturbances of hard tissue growth due to soft tissue damage; (3) genetic changes; (4) changes caused by diseases; and (5) the results of normal functioning of the conodont elements. The frequency of occurrence is analyzed for the various pathology types. [ABSTRACT FROM AUTHOR]

The Devonian and Early Carboniferous brachiopod assemblages of the order Rhynchonellida from Transcaucasia (Nakhchivan Autonomous Republic of Azerbaijan and Armenia) are described. The succession of dominating rhynchonellid superfamilies and ecological types has been identified. Rhynchonellids were numerous in the Devonian; in the Early and Middle Devonian, the representatives of the superfamily Uncinuloidea prevailed. Their relict species survived up to the beginning of Famennian. The free-lying and anchoring cavern-dwelling rhynchonellids dominated in the Early and Middle Devonian. This ecological subtype is recognized for the first time. The rhynchonellid taxonomic and ecological groups changed at the Frasnian–Famennian boundary but rhynchonellids remained a significant part of the brachiopod fauna. The variability of rhynchonellids decreased at the Famennian–Tournaisian boundary but the superfamily Rhynchotrematoidea and the rhynchonellid anchoring ecological type continued to dominate starting from the Frasnian. The role of Rhynchonellida in the Early Carboniferous brachiopod fauna is insignificant. The decrease of variability within some zones is probably connected with taphonomic conditions. [ABSTRACT FROM AUTHOR]

Information on Devonian and Carboniferous paleosols is limited. In this paper, published data (about 50 sources) on findings of these paleosols mostly on the territory of paleocontinents Laurussia and Pangea are summarized. For visualization of this information, sketch maps of paleosol distribution for Devonian, Mississippian, and Pennsylvanian times have been developed. Their analysis shows that most of Devonian paleosols belonged to the groups of azonal and intrazonal soils; soils of wetlands predominated. The discoveries of Middle and Late Devonian zonal soils—Oxisols and texturally differentiated Alfisols—in the area of Voronezh High (south Russia) are unique. Most of Mississippian paleosols also belonged to azonal and intrazonal soils. The wide distribution of wetland paleosols in the Mississipian subperiod was also reflected in the increased area of coal basins (8% of land in comparison with 1% in Devonian). In the area of the Moscow sedimentary basin, along with Histosols, zonal paleosols—Spodosols and others—have been described. Pennsylvanian soil cover consisted of azonal, intrazonal, and zonal soils. In North America and Western Europe, swampy soils were still widely distributed (22% of land was occupied by coal basins). Oppositely, in the area of the Moscow sedimentary basin, Pennsylvanian paleosols of semiarid and arid ranges with palygorskite as the major clay mineral were widely present. The differentiation of Pennsylvanian soil cover of Laurussia and Pangea reflects the changes in climatic zonality of the planet with an increase in the degree of climatic contrast. [ABSTRACT FROM AUTHOR]