Pelagic, outer-shelf sedimentary successions across the Devonian-Carboniferous boundary (DCB) in the western Graz Paleozoic at Trolp (Eastern Alps, Austria) display exceptional, continuous limestone facies of the Hangenberg Crisis interval. These enable the study of conodont successions, lithofacies, and geochemistry without noteworthy interruptions by siliciclastic intervals, which are equivalents of the Hangenberg Black Shale and Hangenberg Sandstone. The praesulcata, kockeli, and sulcata/ kuehni conodont Zones are recognized by stratigraphically significant markers in the early siphonodellids and early protognathodids within thin-bedded limestones. The major conodont biofacies change and initial mass extinction phase ( costatus-kockeli Interregnum) of the Hangenberg Crisis is succeeded by radiations among conodonts in the kockeli and sulcata/kuehni Zones. Carbon isotopes (delta 13 C carb ) record positive excursions and enhanced C org burial episodes; the characteristic signals can be used as chemo-indicators of the early, middle and late phases of the Hangenberg Crisis. The global common Siphonodella sulcata Morphotype 5 and Protognathodus kuehni have their first occurrence at the base of the Tournaisian at Trolp and elsewhere in Europe, Asia and North Africa, and thus can be used to define the base of the sulcata/kuehni Zone and the current DCB level. ` Protognathodus faunas with a high morphological variability are recorded in the praesulcata and kockeli Zones, but spread mainly in the sulcata/kuehni Zone, or even later in the lower Tournaisian. Therefore, the extended kockeli Zone suggested recently, and even leaves the current DCB level undivided, as well as the use of Protognathodus kockeli as index fossil for the DCB, are not applicable as suggested herein. A precise biozonation concept as well as multidisciplinary approaches used at Trolp are needed for understanding ultimate causes of the 1st order Hangenberg mass extinctions and major environmental changes at the DCB. Multidisciplinary approaches comprise taxonomically significant index conodonts, extinctions and radiations, as well as lithofacies and isotopic analyses. These markers at Trolp can be well correlated with those from many other settings worldwide, reflecting the global significance of the Graz Paleozoic.

The Devonian/Carboniferous (D/C) transition is characterized by a major transgressive/regressive cycle which led to a widespread ocean anoxia known as the Hangenberg Black Shale Event (HBSE), as well to a major sea-level fall (Hangenberg Sandstone Event, HSSE), recognized around the world. Both events are known as the Hangenberg Crisis. In order to examine the D/C transition in shallow water environment, the Mighan section in eastern Alborz was studied in terms of conodont biostratigraphy and stable isotope geochemistry. Twenty-five conodont species belonging to seven genera were identified and 5 conodont zones discriminated; namely, the Bispathodus aculeatus aculeatus Zone, Bispathodus costatus Zone, Bispathodus ultimus Zone, Siphonodella praesulcata Zone, costatus-kockeli Interregnum, and the sulcata Zone. Below the Devonian–Carboniferous boundary (DCB), the Hangenberg Black Shale and Hangenberg Sandstone equivalents were recognized, representing the Hangenberg Crisis that highly affected trilobite, ammonoid, brachiopod and conodont faunas at Mighan and worldwide. The kockeli Zone of the latest Famennian is missing at Mighan due to the lack of conodonts, probably related with the major environmental changes linked with the Hangenberg Crisis recognizable worldwide. Carbon isotopes measured of micrites from Mighan indicate a proximal depositional environment of a shallow shelf with terrestrial input and the oxygen isotope values from conodont apatite suggest warm seawater temperatures of tropical and subtropical setting in the study area.

Background Influenza A(H1N1)pdm09 virus entered the human population in2009 and evolved within this population for more than ten years. Despitegenetic evolution no remarkable changes in the antigenic reactivepattern of these viruses were observed so far. Methods Primaryrespiratory samples of the German influenza virological sentinel wereinvestigated by qPCR. Influenza virus-positive samples werecharacterized genetically and antigenetically. Results In December 2019,a antigenic drift variant characterized by an N156K substitution in thehemagglutinin of influenza A(H1N1)pdm09 virus emerged in Germany, whichexhibited a reactivity to ferret antiserum that was an average 6 log2lower than the vaccine virus A/Brisbane/02/2018 and the otherA(H1N1)pdm09 viruses circulating in the influenza season 2019-2020.These viruses accounted for 20% of all A(H1N1)pdm09 virusescharacterized in the German influenza sentinel. Patients infected withthese viruses had a shorter median time period of medical consultationafter onset of symptoms and were more frequently treated withneuraminidase inhibitors in comparison to patients infected with otherA(H1N1)pdm09 viruses. Conclusions This parallel circulation of twoantigenic variants of A(H1N1)pdm09 viruses which differ remarkably intheir antigenic reactive pattern contributes to a greater variability incirculating influenza viruses and challenges vaccination.

Mycobacterium (M.) abscessus infections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight on M. abscessus genomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patient M. abscessus. Eleven of the 42 CF patients were infected with M. abscessus. Five of these 11 patients were infected with global human-transmissible M. abscessus cluster strains. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence of M. abscessus transmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over 4.5 years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from the embABC (arabinosyltransferase) operon, betA (glucose-methanol-choline oxidoreductase) and choD (cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy of M. abscessus populations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies against M. abscessus infections are explored.

AbstractMycobacterium (M.) abscessusinfections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight onM. abscessusgenomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patientM. abscessus. Eleven of the 42 CF patients were infected withM. abscessus. Global human-transmissibleM. abscessuscluster strains were isolated from five of these 11 patients. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence ofM. abscessustransmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over four years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from theembABC(arabinosyltransferase) operon,betA(glucose-methanol-choline oxidoreductase) andchoD(cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy ofM. abscessuspopulations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies againstM. abscessusinfections are explored.

Thirty Devonian-Carboniferous Boundary sections of the Rhenish Slate Mountains and adjacent subsurface areas are reviewed with respect to litho-, event, conodont, ammonoid, sequence, and chemostratigraphy. In the interval from the base of the uppermost Famennian (Wocklum Beds, Wocklumian) to the base of the middle Tournaisian (base Lower Alum Shale), 11 conodont and 16 ammonoid (sub)zones are distinguished. The terminology of the Hangenberg Crisis Interval is refined, with an overall regressive Crisis Prelude below the main Hangenberg Extinction, which defines the base of the transgressive Lower Crisis Interval (Hangenberg Black Shale). The glacigenic and regressive Middle Crisis Interval (Hangenberg Shale/Sandstone) is followed by the overall transgressive Upper Crisis Interval that can be subdivided into three parts (I to III) with the help of conodont stratigraphy (upper costatus-kockeli Interregnum = upper ck I, Protognathodus kockeli Zone, and lower part of Siphonodella ( Eosiphonodella ) sulcata s.l./ Pr. kuehni Zone). Protognathodus kockeli includes currently a wide range of forms, which variabilities and precise ranges need to be established before a precise GSSP level should be selected. Returning to its original definition, the former Upper duplicata Zone is re-named as Siphonodella ( S. ) mehli Zone. It replaces the S. ( S. ) jii Zone, which is hampered by taxonomic complications. The S. ( S. ) quadruplicata Zone of Ji ( 1985 ) is hardly supported by Rhenish data. The entry of typical S. ( S. ) lobata (M1) characterises an upper subdivision (subzone) of the S. ( S. ) sandbergi Zone; the new S. ( S. ) lobata M2 enters much earlier within the S. ( S .) mehli Zone. The ammonoid-defined base of the Wocklum-Stufe (Upper Devonian = UD VI) begins with the Linguaclymenia similis Zone (UD VI-A 1 ). The oldest S. ( Eosiphonodella ) enter within the Muessenbiaergia bisulcata Zone (UD VI-A 2 ). The traditional Parawocklumeria paradoxa Zone of Schindewolf ( 1937 ) is divided into successive P. paprothae (VI-C 1 ), P. paradoxa (VI-C 2 ), and Mayneoceras nucleus (VI-C 3 ) Subzones. In the lower Tournaisian (Lower Carboniferous = LC I), the Gattendorfia subinvoluta Zone is subdivided into G. subinvoluta (LC I-A 2 ) and “ Eocanites ” nodosus (LC I-A 3 ) Subzones. The Paprothites dorsoplanus Zone (LC I-B) can be divided into Pap. dorsoplanus (LC I-B 1 ) and Paragattendorfia sphaeroides (LC I-B 2 ) Subzones. Potential subdivisions of the Pseudarietites westfalicus (LC I-C) and Parag. patens Zones (LC I-D) are less distinctive. The unfossiliferous or argillaceous upper part of the Hangenberg Limestone and the overlying Lower Alum Shale Event Interval remain regionally unzoned for ammonoids.

Devonian/Carboniferous conodonts from the Chelcheli section in the Alborz Mountains were investigated. Although conodonts are generally less abundant in the entire section, important zonal index taxa of the widely applied conodont standard zonation could be used for a precise conodont zonation. Forty-seven conodont species belonging to fifteen genera were identified and led to the discrimination of fifteen conodont zones, ranging from the Palmatolepis minuta minuta Zone into the Scaliognathus anchoralis-Doliognathus latus Zone. At the Devonian/Carboniferous boundary (DCB), characteristic lithologies such as black shales and massive sandstones represent equivalents of the Hangenberg Black Shale and Hangenberg Sandstone. Close to the DCB, there is a small stratigraphic hiatus in the conodont record which might be a result of facies (shallow-water succession with no conodont record and siliciclastic rocks) rather than a period of non-deposition as the sedimentological record seems continuous. Similar to other DCB sections in shallow-water facies in Iran the two biostratigraphically important species Protognathodus kockeli and Protognathodus kuehni do not occur.

Devonian-Carboniferous boundary successions are globally characterized by conodont-free siliciclastics, stratigraphic gaps, or uncertainties among the first occurrence of biostratigraphically relevant index fossils. This resulted from regionally varying palaeoenvironmental conditions caused by global major environmental changes related to the Hangenberg Crisis. The ongoing search for the ultimate causes of mass extinctions at the end of the Devonian requires a fine biostratigraphic framework, which is developed during the last half of century. This study provides new biostratigraphic implications both from the new and re-evaluated conodont material from two classical continuous pelagic limestone successions of two different geological units in Austria. The Upper Famennian and Lower Tournaisian successions at Trolp (Graz Paleozoic) and Grane Schneid (Camic Alps) have been studied in very high-resolution. This study provides the first record of a joint first occurrence of typical morphotypes of \Protognathodus kuehni and Siphonodella sulcata both at Trolp and Grune Schneid in the same biostratigraphic level. This indicates a synchronous first appearance and supports the practicability of the joint sulcata/kuehni Zone previously established. The sampling resulted in a detailed record of the evolution of the biostratigraphically significant Protognathodus fauna, among them Protognathodus kockeli which is currently tested as a potential index for the new Devonian-Carboniferous boundary position. Our analysis revealed taxonomic complexity of Pr. kockeli itself, and in the lineage from its ancestor Protognathodus collinsoni, and to its descendent Protognathodus kuehni. Therefore, using the first occurrence of Protognathodus kockeli as new index fossil for the Devonian-Carboniferous boundary would face the same problem as exists with the current index Siphonodella sulcata which is under revision, and a distinctive conodont-based definition of the system boundary is, under the current taxonomic state of knowledge, difficult to maintain.

Many sections are known from Iran which exhibit sediments across the Devonian-Carboniferous (D-C) boundary. In contrast to the majority of published D-C sections worldwide from pelagic/hemipelagic environments, successions in Iran are mainly composed of shallow-water sediments. Correlation with hemipelagic or pelagic palaeoenvironments remains difficult due to biostratigraphic uncertainties in most sections and/or hiatuses. On the other hand, a limited number of sections dealing with shallow-water facies settings in Iran at this particular time period are known and further research is necessary. Several sections in the Alborz Mountains provide an excellent opportunity to study successions across the D-C boundary in shallow-water facies. In Iran, protognathoids are represented by Protognathodus meischneri and Protognathodus collinsoni . The two biostratigraphically important protognathoids ( Protognathodus kuehni and Protognathodus kockeli ) were not reported or did not occur for the first time in the Late Tournaisian. Early siphonodellids were described instead. In the frame of an Iranian/German research project, we study different palaeoenvironments to reduce serious palaeoenvironmental and palaeogeographical sampling bias which may limit our knowledge on the Hangenberg Event particularly in shallow-water facies. We present a summary on published D-C sections in Iran (Ghale-Kalaghu, Howz-e-Dorah 1, Howz-e-Dorah 2 and Shahmirzad) and sections which are under study (Mighan, Chelcheli and Khoshyeilagh) at the time of this writing.

Abstract The Devonian/Carboniferous (DC) transition is characterized by several transgressive/regressive cycles which led to a widespread ocean anoxia known as the Hangenberg Black Shale Event (HBS), close to the D/C boundary a major sea-level fall (Hangenberg Sandstone, HSS), can be recognized in many sections around the world. Both events known as the Hangenberg Crises. In order to examine the D/C transition, the Mighan section, in Eastern Alborz was selected and studied. The outcrop section is located 25 Kms NE Shahrood city. Frothy five conodont samples (4-5 kg) were systematically taken from 91 ms of the D/C transition interval. Although the conodonts show low frequency but high diversity exhibit important zonal index taxa of the widely applied conodont standard zonation. Twenty-three conodont species belong to five genera were identified and let to discrimination of six following zonal boundaries: Bispathodus aculeatus aculeatus zone, Bispathodus costatus zone, Bispathodus ultimus zone, praesulcata zone, CKl interregnum, sulcate zone. At the D/C transition in Mighan section a black shale and sandstone units are observable that corresponds to the Hangenberg Crisis, that highly affected trilobite, ammonoid, brachiopod and conodont faunas. Kockeli Zone at the latest Famennian is missing at the studied profile due to the major sea level regression. Introduction The study of DC boundary, the mechanism and reasons for the reduction of different fauna, has been an important issue for many paleontologists in the world and in Iran as well. DC boundary is one of the most important boundaries on the Earth, in or shortly before which, an important biological event called Hangenberg event, occurred. The Hangenberg event is one of the major events in the Phanerozoic, and affected more than 20% of marine invertebrate families and 45% of the general population (Simakov 1993; Sepkoski 1996). The Hangenberg event has been identified on epicontinental basins and continental margins in the world. Black shale and Sandstone deposits are very important in identifying this event in different climatic and oceanographic studies. Kaiser (2005) considered that the Hangenberg event is a polyphase crisis, and different groups of fossils from different climates affect, including various rock-diverse changes, and black shales is the main extinction phase of the Hangenberg crisis. These black shales (HBS) occurred during a vast and short-term marine flooding surface within costatus-kockeli interregnum. Successively, a vast eustatic sea-level fall at the end of the Devonian led to deposition of HSS (Becker 1993a). DC boundary is defined via the first appearance Datum (FAD) of the basal Carboniferous conodont Siphonodella sulcata, from Global Stratotype Section and point (GSSP) located in La Serre Trench E’ section, Montag Norie, France (Paproth et al. 1991). However, the decision to define the DC boundary based on the evolutionary species of Siphonodella has some limitations such as: Detection of morphotype Si. sulcata is very hard because Holottape of Si. Sulcata is the interstitial state of Si. sulcata and Si. duplicate (Huddle 1934) and between the Si. praesulcata and Si. sulcata, there are many morphotypes whose exact diagnosis depends on the long-standing personal taste (Kaiser and Coradini 2008). In order to solve this, Corradini et al. (2011) by revising Siphonodellid in the type section and other global sections, divided Siphonodellids into seven groups based on the Platform's shapes, Basal cavity and features of Pseudokeel. The base of Carboniferous system is also defined by the FAD of Protognathodus kuheni (Corradini et al. 2011) and according to new global zonatin of Corradini et al. (2016) and Spalleta et al. (2017) is defined by the FAD of Protognathodus kockelio. The main purposes of this study are to summarize a detailed stratigraphy below and above the D/C boundary in the Mighan section, on the base of conodonts according to new global zonation. Material and Methods During field work, 91m of the Upper Devonian–-Lower Carboniferous succession at Mighan section has been investigate and about 45 conodont samples (3-4kg each) were collected from the Mighan section. The samples were processed with diluted acetic acid (20%). The conodonts were extracted from residues by hand picking and are stored at the University of Isfahan, I.R. Iran and also State Museum of Natural History Stuttgart, Germany. Discussion of Results and Conclusions The Mighan area is located about 20 km northeast of Shahrud city which is located near the Mighan village. Geographical coordinates of the base and top of this studied section are: N: 36° 38′ 38″, E: 54° 57′ 55″ base and N: 36° 38′ 39″, E: 54° 56′ 55″ top. This section includes late Devonian uppermost sediments of Khoshyeilagh Formation (74.47 m thick) and lowermost Carboniferous of Mobarak Formation (16.53 m thick), which subdivided into six lithological units (units A to F). The conodont zonation scheme proposed by Corradini et al. (2016) and Spalleta et al. (2017) for the Upper Devonian and Lower Carboniferous strata were utilized for lower part of the Mighan section in this paper. According to these conodont zonations Protognathodus kuheni is considered as the base of the Carbonoferous. However, due to the lack of Protognathodus in the Mighan section, we used conodont zonations of Kaiser et al. (2009) to define DC boundary based on the appearance of Siphonodella praesulcata and Siphonodella sulcata. Totally five bio-intervals have been discriminated in the Mighan section: Bi. aculeatus aculeatus Zone, Bi. costatusZone, Bi. ultimus Zone,The praesulcta Zone, The Costatus-kockeli interregnum (CKI), andthe sulcata Zone. Field works and lab examinations led to identification of a dark and organic-rich shaley horizon at the D/C transition which corresponds to the costatus-kockeli interregnum (CKI) conodont biozone and are indicative of Hangenberg Crisis. Transgression of seawater and expansion of dark shales caused the organisms to wipe out and following regression formed HSS in the Mighan section. These dark shales are representative of the dominance of dysoxic to anoxic conditions accompanied by low rate of deposition and considerable decline of organisms. The migration of anoxic waters during the transgression of sea water, which is evidenced through the occurrence and increase of conodont species such as Bispathodid, gave rise to the losing habitats, invasion and competition to occupy the habitat and extensive decline of benthic organisms. The reduction of brachiopods, trilobites and ammonoids in the dark shales and topmost beds at the Mighan section are potential documents for this event. Despite intensive sampling in this study, no latest Famennian kockeli Zone was recognized at the studied section implying the presence of disconformity and discontinuity of deposition. Therefore, the basal limestone immediately above the sandstones at the Mighan section is comparable to Early Tournaisian Si. sulcata Zone.

Conodonts of lower Tournaisian successions in the Remscheid-Altena Anticline of the Rhenish Massif (Germany) and from the Moravian Karst of the Bohemian Massif (Czech Republic) have been re-studied based on previous high-resolution conodont stratigraphy. New lower Tournaisian siphonodellids without ornamentation on the oral platform side were recorded here in carbonate pelagic and turbiditic settings. Siphonodella belkai, which was previously unknown in western Europe, is the most abundant species among the unornamented siphonodellids. Two morphotypes of Si. belkai as well as Si. kalvodai sp. nov. are defined herein. The new faunas occur in the jii, sandbergi, and quadruplicata conodont zones. Siphonodella kalvodai sp. nov. has its FAD in the jii Zone, and Si. belkai first occurs in the basal jii Zone in both regions. The basal jii Zone can therefore be correlated with the basal belkai Zone established in neritic and pelagic settings of the East European Platform and Uralian Mountains. The new faunas enable a more precise correlation between lower Tournaisian biozones established previously in Central, South and Western Europe, North America, China, and East European and Uralian regions. Distributional restrictions of unornamented siphonodellids indicate a subordinate ecological significance but points out their palaeogeographic provincialism, tied to the northern Palaeotethys or palaeoequatorial realm.

Abstract Chrono-, litho- and biostratigraphy across the Devonian–Carboniferous transition are reviewed to provide a precise time framework for the global Hangenberg Crisis and for the current search for a revised basal Carboniferous Global Stratotype Section and Point (GSSP). The outer shelf deposits of the Rhenish Massif (Germany) form a lithological standard. Pre- (main Wocklum Limestone), lower (top Wocklum Limestone/Drewer Sandstone to Hangenberg Black Shale), middle (Hangenberg Shale/Sandstone), upper (Stockum Limestone), and post-crisis (Hangenberg Limestone) deposits are defined. Combined with the conodont, ammonoid and miospore zonations and eustatic trends, this succession can be correlated internationally. The contemporaneous successions of the Ardennes serve as a reference for shallow shelf settings. The positive and negative aspects of five options for a redefined Devonian–Carboniferous boundary level are discussed: (1) base of the black shale (main extinction level, base of Bispathodus costatus–Protognathodus kockeli Interregnum and LN Zone), (2) sequence boundary (widespread unconformities) or glacial and regressive peak (base of Hangenberg Sandstone), (3) base of the kockeli Zone and of initial postglacial transgression (base of lower Stockum Limestone), (4) entry of Siphonodella (Eosiphonodella) sulcata (base of upper Stockum Limestone), and (5) base of post-crisis interval (base of Hangenberg Limestone), at approximately the poorly correlated current GSSP level. Due to homonymy, Siphonodella (Siphonodella) hassi Ji, 1985 is renamed as Siphonodella (Siphonodella) jii nom. nov. Consequently, the mid-lower Tournaisian S. (S.) hassi Zone (previous Upper S. (S.) duplicata Zone) becomes the S. (S.) jii Zone.

Abstract The global Hangenberg Crisis near the Devonian–Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called ‘Big Five’ first-order Phanerozoic events. It played an important role in the evolution of many faunal groups and destroyed complete ecosystems but affected marine and terrestrial environments at slightly different times within a short time span of c. 100–300 kyr. The lower crisis interval in the uppermost Famennian started as a prelude with a minor eustatic sea-level fall, followed rather abruptly by pantropically widespread black shale deposition (Hangenberg Black Shale and equivalents). This transgressive and hypoxic/anoxic phase coincided with a global carbonate crisis and perturbation of the global carbon cycle as evidenced by a distinctive positive carbon isotope excursion, probably as a consequence of climate/salinity-driven oceanic overturns and outer-shelf eutrophication. It is the main extinction level for marine biota, especially for ammonoids, trilobites, conodonts, stromatoporoids, corals, some sharks, and deeper-water ostracodes, but probably also for placoderms, chitinozoans and early tetrapods. Extinction rates were lower for brachiopods, neritic ostracodes, bryozoans and echinoderms. Extinction patterns were similar in widely separate basins of the western and eastern Prototethys, while a contemporaneous marine macrofauna record from high latitudes is missing altogether. The middle crisis interval is characterized by a gradual but major eustatic sea-level fall, probably in the scale of more than 100 m, that caused the progradation of shallow-water siliciclastics (Hangenberg Sandstone and equivalents) and produced widespread unconformities due to reworking and non-deposition. The glacio-eustatic origin of this global regression is proven by miospore correlation with widespread diamictites of South America and South and North Africa, and by the evidence for significant tropical mountain glaciers in eastern North America. This isolated and short-lived plunge from global greenhouse into icehouse conditions may follow the significant drawdown of atmospheric CO2 levels due to the prior massive burial of organic carbon during the global deposition of black shales. Increased carbon recycling by intensified terrestrial erosion in combination with the arrested burial of carbonates may have led to a gradual rise of CO2 levels, re-warming, and a parallel increase in the influx of land-derived nutrients. The upper crisis interval in the uppermost Famennian is characterized by initial post-glacial transgression and a second global carbon isotope spike, as well as by opportunistic faunal blooms and the early re-radiation of several fossil groups. Minor reworking events and unconformities give evidence for continuing smaller-scale oscillations of sea-level and palaeoclimate. These may explain the terrestrial floral change near the Famennian–Tournaisian boundary and contemporaneous, evolutionarily highly significant extinctions of survivors of the main crisis. Still poorly understood small-scale events wiped out the last clymeniid ammonoids, phacopid trilobites, placoderms and some widespread brachiopod and foraminiferan groups. The post-crisis interval in the lower Tournaisian is marked by continuing eustatic rise (e.g. flooding of the Old Red Continent), and significant radiations in a renewed greenhouse time. But the recovery had not yet reached the pre-crisis level when it was suddenly interrupted by the global, second-order Lower Alum Shale Event at the base of the middle Tournaisian.

The Upper Muschelkalk in the Central European Basin (CEB) is a key example of eustatic and climatic controls on inland seas. The late Anisian rapid transgression from Tethyan waters culminated in a large semi-enclosed inland sea stretching across the CEB. Subsequently, the slow but successive retreat in the early Ladinian resulted in a small remnant sea. The pronounced stratal pattern architectures are translated into a framework of 3rd- and 4th-order T-R sequences. The latest Illyrian 3rd-order maximum flooding surface corresponds to maximum abundances of carbonates and marine phytoplankton. An euryhaline marine ecology is indicated by prasinophycean algae dominating over acritarchs and delta O-18(p), values of 18.9-22.4%. VSMOW corresponding to Tethyan references. During the 3rd-order regressive phase successive freshening up to hyposaline conditions is indicated by up to 3%. depleted delta O-18(p), values, shifts to more radiogenic Sr-87/Sr-86 ratios and maximum abundances of terrestrial palynomorphs. Likewise, 4th-order T-R sequences are constrained by commutated strata! pattern architectures, palynofacies and geochemistry.The favourable correlation of middle Triassic 3rd-order sequences of Tethyan and peri-Tethyan basins demonstrate the principle control of circum-Tethyan eustatic cycles. 4th-order sequences are evident and, although not yet correlatable in detail, indicate 10(6)-year scale eustatic cycles which may be attributed to glacioeustatic sea-level changes. The subordinated control of arid to semiarid low latitude and semihumid to humid temperate mid latitude climates affected the Upper Muschelkalk Sea in particular during 4th-order sea-level lowstands. Substantial fresh water input from Scandinavian sources caused temporal stratification leading to stagnant bottom waters and/or sediments as indicated by palynofacies and U/Th and Ni/Co redox indices. The herein reconstructed middle Triassic zonal climates are in agreement to previously published Late Triassic zonal climates. (C) 2015 Elsevier B.V. All rights reserved.

One of the unornamented species - Siphonodella belkai - described from Poland and further known from Russian Tournaisian is the index taxa of eponymous belkai conodont zone distinguished in these regions. Sudden ventral narrowing of Si. belkai platform elements resemble platform features of Si. sandbergi and, moreover, presence of three or more (up to 7) rostral ridges is common characteristic with Si. quadruplicata. Because Si. belkai has been defined by Dzik in 1997, confusing of Si. belkai with Si. sandbergi and Si. quadruplicata is common in older, but, even in more recent publications. The misleading determination leads to stratigraphic discrepancies and older sediments of the hassi Zone are identified as younger ones (sandbergi and quadruplicata zones). The lower Tournaisian deep-water limestones (upper to lower slope) in the Rhenish Slate Mountains (Oese, Oberrodinghausen) and Moravian Karst (Lesni lom Quarry) recently yielded relatively abundant Si. belkai (Fig. 1ab) with rare unornamented Siphonodella sp. (Fig. 1c), accompanied by conodonts typical for the hassi and sandbergi zones. The first appearance datum (FAD) of Si. belkai matches with FAD of Si. hassi and therefore bases of these zones can be tentatively correlated.