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The age of the Silurian “Lower Red Beds” (LRBs), which occur widely in South China, has long been controversial because of the scarcity of index fossils. Here, we report a fauna with abundant trilobites from the LRBs in Wuhan, Middle Yangtze region, consisting of Aulacopleura (Paraaulacopleura) pijiazhaiensis, ‘Encrinuroides’ yichangensis, Gaotania hubeiensis, Hyrokybe gaotanensis, Japonoscutellum yichangense, Latiproetus latilimbatus, and Ptilillaenus lojopingensis. These trilobites are common in the Leijiatun, upper Xiangshuyuan, Shihniulan, and Lojoping formations in the Upper Yangtze region, and belong to the middle to upper Aeronian Ptilillaenus or ‘Encrinuroides’–Ptilillaenus–Latiproetus assemblages. The discovery of this trilobite assemblage suggests that the LRBs are probably partly of middle–late Aeronian age in the Middle Yangtze region. Thus, the lower boundary of the LRBs is likely diachronous in the Yangtze region, ranging from the middle–late Aeronian to the early Telychian. The discovery of the Ptilillaenus assemblage in the Wuhan LRBs expands the paleogeographic distribution of this assemblage and provides evidence of deeper depositional environment of the LRBs in the study area versus shallow waters in other areas of the Yangtze region.

The Hongguleleng Formation, the highest and most important Devonian marine carbonate horizon in western Junggar, contains an endemic shallow-water Icriodus–Polygnathus conodont fauna with rare palmatolepids and other genera. The conodont faunas from the Bulongguoer and the Wulankeshun sections are similar, with high abundance (about 40%) of endemic taxa (13 taxa), indicating isolation of the Junggar Basin during early Famennian. Non-endemic species in the faunas suggest that the Lower Member of the Hongguleleng Formation is assignable to the Pa. rhomboidea Zone to the Pa. marginifera marginifera Zone of early Famennian, not including the Frasnian–Famennian boundary. The Upper Member may be of late Famennian–early Tournaisian in age on the basis of our preliminary faunal analysis.

The percentage of filter-feeder species in benthic ostracod assemblages shows evident changes during the Late Devonian Frasnian–Famennian (F–F) transition with two sharp rises in the event stratal interval based on materials collected from the Yangdi section, South China. Neither anoxia nor oligotrophy, eustasy should have been the only primary cause of filter-feeders signal in the F–F event. The sea level fall and rise would create deteriorative environmental conditions such as lower oxygenation and less nutrients, which altogether reduced the diversity and abundance of the benthic ostracods in the F–F transition. The percentage of filter-feeders showed a decrease during the regression, and vice-versa. Therefore, the filter-feeders may be potentially an indicator of sea level changes in the F–F event.

Trace fossils are special objects in the study of predator–prey interactions in the fossil record. Here we report on diverse morphological types of the gnathostome fish hunting trace Osculichnus from the Upper Devonian of South China. The studied Osculichnus specimens occur as groups of bilobate mounds on the sole of fine- to medium-grained quartz sandstones from the estuarine-embayment depositional system of the Upper Devonian Wutong Formation in Wuhan city. The fish feeding trace Osculichnus is closely associated with the highly regular, branched sinuous trace Sinusichnus sinuosus on the bedding plane. Previously, Sinusichnus sinuosus has been typically reported from Late Cretaceous to Miocene marginal-marine sediments, with two records in the Lower and Middle Triassic of South China, and is generally regarded as the burrows of decapod crustaceans. The discovery of Sinusichnus sinuosus in the Upper Devonian, though of relatively small diameter (0.4–4.3 mm) than its Mesozoic and Cenozoic counterparts, extends its stratigraphical distribution and is suggestive of some primitive, small-sized decapod crustacean producers. The Osculichnus makers possibly preyed upon the Sinusichnus makers or other small invertebrates in the sediments. The overall shape and morphological details of the Late Devonian Osculichnus suggest lungfish as candidate trace makers. The fish hunting traces and associated trace fossils from South China thus provide unique insights into the palaeoecology of Late Devonian fishes.

In this study, systematic conodont biostratigraphy and cyclostratigraphy are carried out on Ordovician sections from the North China and South China blocks. The Liangjiashan section, situated on the North China Block margin, accumulated shallow marine carbonate during the Early Ordovician. The Huanghuachang section (GSSP for the Dapingian Stage), situated on the South China Block margin, accumulated thinly bedded carbonates and minor clastics in a deep shelf environment. Conodont biostratigraphy and 405-kyr long-eccentricity cycles interpreted from the Liangjiashan and Huanghuachang sections are used to establish an Astronomical Time Scale (ATS) for the Early–Middle Ordovician period. The ATS indicates that the duration of the Floian Stage is 7.08 ± 0.405 Myr. The temporal ranges of Lower–Middle Ordovician conodont biozones are also estimated: the durations of the Serratognathus bilobatus, Serratognathus extensus, Oepikodus communis, Oepikodus evae, and Baltoniodus triangularis zones are 1.0 Myr, 5.1 Myr, 0.2 Myr, 0.8 Myr, and 0.2 Myr, respectively. The evolution of the ratio of obliquity to total power and short-eccentricity power to total power depicts periodicities of 1 Myr for the s4–s3 term, and 1.9 Myr shifting to 1 Myr for the g4–g3 term. The shift in the g4–g3 term may indicate a chaotic transition in the Mars and Earth orbital motions from a (s4–s3)–2(g4–g3) to (s4–s3)–(g4–g3) resonance state during the Early Ordovician.

Tentaculitoids have long been recognised as an enigmatic group of marine invertebrates that are widely distributed and highly diversified in the Silurian and Devonian strata. A tentaculitid assemblage is described herein from the Nagaoling Formation spanning the Lochkovian–Pragian boundary in Nanning, South China. Six new species are recognised: Tentaculitesbrevitenui n. sp., Lonchidium cylicus n. sp., Bicingulites nanningensis n. sp., Odessites aurisites n. sp., O. nahongensis n. sp. and Volynites nagaolingensis n. sp. are diagnosed. Two species Podolites sp. and Seretites sp. and one population Uniconus spp. are described in open nomenclature. All above tentaculitid genera can be detected in the Silurian strata from Sweden. The tentaculitids from South China allow transitional skeletal characters between benthic and planktonic tentaculitoids to be described, including conch size, conch wall thickness, septum number and the relationship between external and internal wall sculptures. The fossil assemblage, sedimentary rocks and taphonomic characters indicate that tentaculitids of Nagaoling Formation in South China were deposited in an outer shelf region with weak hydrodynamic condition.

This study focuses on the Late Devonian ostracods and their responses to the F—F (Frasnian-Famennian) event based on abundant materials collected from the Yangdi and Nandong sections in South China. More than half (53%) of the benthic ostracod species disappeared at the F—F boundary in the Yangdi section of slope facies, whereas most benthic ostracod species survived the F—F crisis in the Nandong section of basinal facies, with the extinction of some pelagic entomozooidea. In view of a higher extinction rate (more than 65%) of ostracod species in the shallow-water Xikuangshan section, we deduce that ostracods in varied environments responded to the F—F event differently. Namely, from the carbonate platform, slope, to basinal settings, the extinction rate of benthic ostracods at the F—F transition decreased with increasing water depth. Nevertheless, the F—F event caused substantial loss among pelagic entomozooidea lineages. The extinction pattern of benthic and pelagic ostracods in F—F event in South China is similar to the situation in Europe. But the extinction rates of benthic ostracods in shallow water and slope in Europe seems to be higher than that in the same situation in South China. The abundance and diversity of ostracods decreased and some species even disappeared in anoxic environments across the F—F boundary in South China, when there were rapid changes in the palaeotemperature of surface sea water.

One kind of mysterious underwater circle observed on the seafloor near southern Amami-Oshima Island in subtropical Japan has attracted widespread attention, but its origin has long been unknown. In recent years, based on successive underwater photography, they were shown to represent the patterned structures constructed by male pufferfishes. Here we present a large radial trace fossil from the Upper Devonian Hongguleleng Formation in western Junggar, Xinjiang, northwestern China. They are circular or near-circular patterned structures consisting of numerous radial grooves and ridges. Based on morphological analysis of these specimens and comparison with the modern patterned structures made by pufferfish for courtship, we suggest that this trace fossil may be patterned structure made by male fish in the Devonian to attract females. If true, these structures would be the first reported example of courtship behaviour in the trace fossils of fish, and suggest that animal courtship behaviour has existed for at least 360 million years. These trace fossils provide new material for research on the breeding strategies and sexual selection of Devonian animals, and new insight on the origin and evolution of courtship behaviour.

The Late Devonian Frasnian–Famennian (F–F) event, consisting of the Lower and Upper Kellwasser events, had a severe impact on shallow-water ecosystems, while the effect on deep-water ecosystems is ambiguous. In order to recognize the Kellwasser events and to evaluate their influences on the deep-water ecosystems, a newly refined conodont biostratigraphic framework spanning the Lower Palmatolepis rhenana Zone to the Pa. delicatula platys Zone has been established in the Nandong section (basinal facies), Guangxi, South China. The Upper Devonian Lower and Upper Kellwasser horizons (LKH and UKH) have been recognized in the deep-water facies on the basis of lithological variations, biological turnovers, and positive carbon isotope (δ13Ccarb) excursions. The LKH is characterized by the enrichment of marine nektonic communities (e.g. conodonts, homoctenids, and entomozoacean ostracods), whereas the top of the UKH is barren of fossil organisms, suggesting that the Upper Kellwasser event had a more severe effect on nekton than the Lower Kellwasser event. The Upper Kellwasser (UK) δ13Ccarb positive excursion lags behind the enrichment of Cu, Ni, Mo and V, indicating that the UK δ13Ccarb positive excursion was probably related to elevated primary productivity, which induced oxygen depletion in the water column. The UK δ13Ccarb positive excursion peak prior to the F–F boundary indicates a more limited effect of riverine influx on the deep-water setting, which suggests that the regional palaeogeographic configuration played an important role in the carbon cycle.

Trace fossils are important evidence of benthic activity and proxies of bottom and interstitial water oxygen content, making them a promising tool to understand the oceanic redox evolution and extinction patterns during the end-Permian mass extinction (EPME). Detailed bed-by-bed ichnologic studies were performed at a high-resolution scale from two uppermost Permian sections (Shangsi and Dongpan) in South China, documenting the presence of Chondrites targionii, Chondrites isp., Nereites isp., Planolites isp. A, Planolites isp. B, Palaeophycus isp., Phycosiphon incertum, Thalassinoides isp., and Zoophycos isp. The uppermost Permian strata at the Shangsi section mainly comprise siliceous limestone interbedded with illite-montmorillonite claystone and shale, recording a deep shelf setting. The uppermost Permian strata at the Dongpan section consist of mixed chert, mudstone and claystone, formed in a slope environment. Bioturbation index in uppermost Permian strata is mostly 1–2, but with thin intervals reaching 3–4. Fluctuating bioturbation intensities, ichnofaunal composition (Thalassinoides, Planolites, Zoophycos) and ethologies, as well as the ratio of highly reactive iron to total iron (FeHr/FeT) and the proportion of the highly reactive iron pool in the form of pyrite (Fepy/FeHR) suggest that bottom and interstitial oxygen levels were not permanently anoxic/euxinic, but were interrupted by brief periods of aerobic conditions during the latest Permian. Three bioturbation phases in the EPME are identified. Phase I is characterized by the absence of typical pascichnia ichnotaxa (e.g. Nereites isp.) and relatively large fodinichnia burrow (e.g., Planolites isp. B; Zoophycos isp.). Phase II mainly consists of smaller Planolites isp. A, Thalassinoides isp. and Chondrites isp., recording a transition from softground to firmground. Only occasional smaller Planolites isp. A occur in Phase III without any associated vertical burrows. Ichnodiversity and bioturbation index from Phase I to Phase III show a step by step decline, corresponding to the two-stage extinction patterns. Long-term environmental stress (e.g., oceanic anoxia, volcanic winter, global warming, ocean acidification, hypercapnia) may have played major role in the collapse of the infaunal ecospace and only facies-crossing, highly tolerant, opportunistic organisms may have persisted in otherwise vacant ecological niches in the aftermath of the extinction.

The impact of climate change on biodiversity has been the focus of studies on the Phanerozoic biotic crises. However, it is still controversial whether climate change has caused the Frasnian–Famennian (F–F) biotic crisis since there is no unequivocal view on the global climate change during this critical period. In order to reconstruct palaeotemperatures during the F–F transition in South China (eastern Palaeotethys), a high-resolution oxygen isotope ( δ 18 O PO 4 ) record was obtained based on 104 measurements of conodont apatite from the Yangdi section. The oxygen isotope record based on mono-generic samples reveals an increase in δ 18 O PO 4 by 0.7‰ in the Lower Kellwasser horizon (LKH) and 1.4‰ in the Upper Kellwasser horizon (UKH), translating into low-latitude surface water cooling of ∼3 °C and ∼6 °C, respectively. These two δ 18 O PO 4 shifts agree well with the time-equivalent δ 18 O PO 4 records from the western Palaeotethys, suggesting that two climate cooling pulses in conjunction with the deposition of the Kellwasser horizons are a global signal during the F–F transition. The positive shift of δ 18 O PO 4 coincides with positive excursion in carbon isotope of carbonates ( δ 13 C carb ) in the UKH, indicating that enhanced burial of organic carbon resulted in a drop in atmospheric p CO 2 and thus global climate cooling. Cooling started immediately before the Upper Kellwasser biotic crisis, with the lowest temperature documented at the top of the UKH. Climate cooling during the deposition of the LKH is observed in conjunction with the sharp decline in metazoan reefs. The coincidence of cooling and the Kellwasser biotic crisis suggests that global cooling played a major role in the collapse of ecosystems.

The Luoping Biota discovered from the early Middle Triassic (Anisian) Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic recovery following the end-Permian mass extinction. Contemporaneously preserved are prolific trace fossils, which offer good opportunities to understand the palaeoecology of marine invertebrates from a fully recovered shallow marine ecosystem. Here we present a newly discovered sinuous branching burrow from the fossil-bearing unit in Member Ⅱ of the Guanling Formation. Several features, including the horizontal regular sinuous nature, the branching pattern, typical H-junction, and the small wavelength/amplitude ratio of these sinuous structures within the burrow systems justify assignment of these traces as Sinusichnus sinuosus, a trace possibly produced by decapod crustaceans. Close association of S. sinuosus with Rhizocorallium commune suggests a deposit-feeding strategy of these trace makers. The newly reported Anisian material from the Guan-ling Formation in Luoping represents first report of Sinusichnus from South China. The global record of Sinusichnus occurrence suggests that these burrows might have an older history than Early Middle Triassic.

Thirty-seven ostracod species belonging to 25 genera from the Devonian-Carboniferous (D/C) transition in Dushan of Guizhou, South China are identified and figured. The stratigraphical distribution of ostracods in the Baihupo section suggests that the D/C boundary should be fixed in the basal part of the Tangbagou Formation, which is also the boundary between Gelaohe and Tangbagou formations. The ostracod assemblages from the Gelaohe Formation belong to the Eifelian Mega-Assemblage, incorporating palaeocopid and smooth-podocopid associations, which implies a nearshore-offshore palaeoenvironment, while the ecological assemblages of ostracods from the Tangbagou Formation correspond to a smooth-podocopid association that indicates an offshore palaeoenvironment. There was probably a transgression during the D/C transition when Gelaohe and Tangbagou formations were being deposited in Dushan of Guizhou.

Graphoglyptids are biogenic structures commonly found in deep-sea flysch deposits and occasionally detected on the modern deep-sea floor. They extend principally horizontally and take a variety of geometric patterns, whose functional morphology remains an enigma in ichnology and paleoceanography. Based on published materials from 1850 to 2017 (79 ichnotaxa from 28 ichnogenera of graphoglyptids) and systematic observations of one of the largest deep-sea trace fossil collections in the world, this paper proposes that topological analysis is an important ingredient in the taxonomy and functional interpretation of graphoglyptids. Accordingly, graphoglyptids are classified into line, tree, and net forms by their key topological architecture, and are further attributed to 19 topological prototypes by detailed secondary topological features. Line graphoglyptids are single-connected structures with uniform tunnel width, representing primarily the feeding patterns of solitary animals. Tree graphoglyptids, the most diverse architectural group of graphoglyptids, are ascribed to 11 topological prototypes according to the connectivity features of burrow segments and the number and distributional pattern of the branching points. Net graphoglyptids are subdivided into three topological prototypes on the basis of the connectivity features and/or the regularity of the meshes. Multiconnected net forms are considered as a continuous morphological spectrum with different levels of complexity in the net formation. The various connected components in multiconnected tree and net graphoglyptids generally exhibit small and uniform tunnel diameter in a given structure (suggesting a tiny trace maker[s]). The whole structure shows relatively extensive linear or surface coverage and overall good preservation, indicating sustained processes of burrow construction. It is highly probable that certain multiconnected tree and net graphoglyptids represent some emergent patterns from self-organized collective behaviors of conspecific animals. Graphoglyptids thus provide us with a new perspective on the study of solitary and collective behaviors of macrobenthos in the deep-sea environment.

Wangshangkia, a new genus of Ostracoda, from the Late Devonian in Dushan of Guizhou, South China, is described. This genus belongs to the family Bairdiocyprididae Shaver, 1961 and includes two new species, i.e. Wangshangkia dushaniensis and W. bailouiensis. The new genus is characterized by a wide ventral carina with radial striae. It is reported from the Famennian of South China and disappeared just below the Devonian-Carboniferous boundary. Wangshangkia is essentially a benthic crawler and is restricted to the shallow-marine depositional environment with a low hydrodynamic condition.Wangshangkia: urn:lsid:zoobank.org:act:34BF01D4-D202-492D-8E27-BC508EF7EFFBW. dushaniensis: urn:lsid:zoobank.org:act:D267C362-7510-4D19-996B-EA1848D7D025W. bailouiensis: urn:lsid:zoobank.org:act:FE988AA0-7363-4D9E-A5AB-1526C8DBCDD9

The Late Devonian is considered as a crucial climatic transition from the Devonian greenhouse to Carboniferous icehouse. Published Late Devonian marine palaeotemperature records are mainly based on conodont δ18Oapatite data from the Rheic Ocean. In order to reconstruct palaeotemperature variations in the eastern Palaeotethys, oxygen isotopes were measured on the latest Givetian to latest Famennian conodonts from the Lali section (South China). Assuming constant seawater δ18O, the early to middle Frasnian is marked by a warming trend (−1.5‰ shift in δ18Oapatite), with warmest temperatures reconstructed in FZ 11 (FZ = Frasnian Zonation). Late Devonian cooling during the middle to late Famennian (velifer to ultimus Zone) is documented by a long-term positive δ18Oapatite shift of +2‰. This increase corresponds to a similar δ18Oapatite increase in the Rheic Ocean and can be explained by cooling as well as the formation of ice masses as evidenced by the occurrence of glacial sediments in Gondwana and Euramerica during the late Famennian. The Late Devonian δ18Oapatite record largely matches 2nd-order T-R cycles. The δ18Oapatite record from the Lali section shows several short-term positive excursions coinciding with Late Devonian bio-events as the Middlesex (+0.5‰ δ18Oapatite), Lower Kellwasser (+1‰ δ18Oapatite) and Upper annulata (+0.8‰ δ18Oapatite) events. However, due to the lower sampling resolution of the F-F (Frasnian-Famennian) boundary interval, we did not recognize a positive shift in δ18Oapatite for the Upper Kellwasser event as reported from other sections.

The ichnogenus Helminthorhaphe is a meandering trace fossil valuable to the study of movement behaviours of the trace-making marine invertebrates. In this work, we studied systematically the morphology of selected examples of Helminthorhaphe from the Upper Cretaceous to Miocene by means of primary morphological constructs, morphometrics, and theoretical morphological models. Eleven morphological constructs encompassing meander arrangement, meander tip, and meander course properties are established to illustrate the essential morphological features of meanders, which cover key aspects of the motion and navigation capacities of Helminthorhaphe makers. Tunnel diameter, meander width, and meander length are extracted to explore the size range of Helminthorhaphe , from which an exceptionally large end member is recognised, H . magna ichnosp. nov. Meander width versus tunnel diameter ratio and the fractal dimension of Helminthorhaphe are two prominent morphometric parameters that characterise the average closeness and space usage of the meanders, respectively, which aid differentiation between ichnospecies. Helminthorhaphe miocenica , H . magna , H . flexuosa , and H . japonica generally conform to a series of increasing closeness and space usage of the meanders. Theoretical morphogenetic analysis of the meander-generating process of Helminthorhaphe based on the bilateral phobo-thigmotactic robot car model reveals that the tempo and hierarchy of bilateral movement differentiation contribute to the formation of primary terminal U-turn at the meander tip, as well as lower-level meander-course undulations. The meander tip property proves to be an important morphological feature with biomechanical and neurobiological implications on the body flexibility and lateralisation in the nervous system of Helminthorhaphe producers. Larger-scale meander arrangement styles suggest that Helminthorhaphe makers potentially possessed certain radial or concentric spatial cognition of the environment. With an emphasis on theoretical morphogenetic analysis, this study provides a preliminary attempt in linking ichnology with behavioural, neurobiological, and intelligence sciences.

An exceptionally preserved biota is described from the middle Telychian (Llandovery, Silurian) Fentou Formation of Wuhan, Central China, which preserves nontrilobite arthropods, cnidarians, echinoderms, sponges, fish, and algae as well as abundant shelly fossils and trace fossils in the Skolithos-Cruziana ichnofacies. This biota can be divided into two assemblages on the basis of the biological characteristics, fossil-bearing strata, and their sedimentary environments. Assemblage 1 comprises nonbiomineralized phyllocarids, Sphenothallus, conulariids, complete crinoids and stelleroids, and Burgess Shale–type sponges as well as some uncertain fossils in taxonomy and abundant marine shelly fossils. Assemblage 2 consists of numerous eurypterids, agnathans, chondrichthyes, and a few conulariids, algae, as well as shelly euryhaline fossils. Discoveries of the Fentou biota expand the temporospatial distribution and sedimentary environment of the exceptionally preserved Silurian biota and advances a deepe...

The cephalon of the trilobite Phacopidae was usually separated from the thorax during moulting, and abandoned near the trunk. We statistically evaluated the distribution pattern of the cephala of Omegops cornelius, and found that near 70% of the total cephala were displaced on the right side, from the Upper Devonian deposits of the western Junggar in Northwest China. Omegops cornelius might have actively pushed the cephalon to the right of its body during moulting, indicating their preference to move counterclockwise. This preferred movement direction manifested the behavioural asymmetry in trilobites. A different type of asymmetry has been observed in Phacopidae Plagiolaria nandanensis from the Lower Devonian of Guangxi in South China, where about 67% of the cephala were found on the left side of the trilobite trunks. So the behavioural asymmetry may be diverse (or opposite) in different species of trilobites, and the reasons for the asymmetric moulting and movement patterns of the above two trilobites are likely related to their body structures, or their living environments. These new materials provide evidence for studying the origin and evolution of behavioural asymmetry.

International audience; The microfossil-based pattern of the Devonian land plants of China is revised and discussed based on a newly comprehensive dataset. Such dataset compiles the chronostratigraphical distribution of 1677 species belonging to190 genera of spores and pollen from the primary literature, which recovers the fossil history of Chinese terrestrial palynofloras. From this, we describe the patterns and biodiversity dynamics using both range-based and occurrence-based data to illustrate the main fluctuations of Devonian taxonomic richness, including rarefaction for filtering out uneven sampling. Results show that the apparent terrestrial palynofloral diversity of China increases progressively from the early to mid-Devonian, with a genuine Givetian peak followed by a plateau persisting during the Late Devonian. Results further suggest that sampling effects may strongly influence the perception of biodiversity trends of China, as well as that the observed Late Devonian taxonomic diversification may have been greatly overestimated. Compiled evidence is discussed on the light of the global evolution of marine-terrestrial ecosystems. We hypothesize that the rise of Devonian floras may have played a remarkable role in an oceanic oxygenation event during this Period.

Acritarchs and prasinophytes have generally been considered as organic-walled phytoplankton, and their distribution patterns play a significant role in palaeogeographical and palaeoclimatical reconstructions. In this paper the palaeobiogeography of Late Devonian phytoplankton (mainly Famennian) is quantitatively analyzed based on a global database consisting of 95 genera from 15 geographical units. The data are analyzed using cluster analysis, nonmetric multidimensional scaling, and minimum spanning tree analysis using the Jaccard, Ochiai, Kulczynski, and Yule's Y similarity coefficients. The results show that there was provincialism in the Late Devonian and three phytoplankton palaeobiogeographical realms could be identified: the West Gondwana, East Gondwana, and Boreal realms. There is a high degree of similarity between phytoplankton assemblages in East Gondwana (especially those in Australia and Iran) and Euramerica. Portugal (of the Iberian-Armorican block) was situated to the north of Algeria and probably acted as a stepping stone between Euramerica and West Gondwana. The closed oceanic surface circulation pattern in the Proto-Tethys Ocean between Euramerica and East Gondwana might have hindered the exchange of phytoplankton between East and West Gondwana. The phytoplankton province that had been typically confined to the higher latitudes was still present, while its characteristic genera gradually dispersed into the lower latitudes in the Late Devonian. There is a high similarity between phytoplankton assemblages from the western Junggar of Xinjiang, NW China and Euramerica. Latitude- and current-influenced palaeotemperature and oceanic circulation patterns are considered to have been the major determinants of the geographical distribution and evolution of marine phytoplankton in the Late Devonian.

Accurately identifying contourites and analysing the interaction between turbidity flows and bottom currents from the mixed turbidite-contourite systems (MTCSs) in the deep-sea environments are still challenging. Reports on ancient MTCSs are scarce and most of them remain contentious. This study describes at various scales the sedimentological and sedimentary geological characteristics of the Middle Ordovician Yingtaogou Formation, which is identified as a MTCS, from the western margin of the North China Craton (NCC). Twelve typical lithofacies are recognised in the Yingtaogou Formation, which can be grouped into four facies associations interpreted to reflect various deposition from turbidity flow, contour current, debris flow, and hemipelagic settling in the slope–abyssal plain environment. The evidence for contourites is four-fold. Firstly, the palaeocurrent direction based on flute casts on turbidite soles is almost perpendicular to that indicated by traction current structures. Secondly, it is possible to observe a variety of traction current structures (large-scale cross-bedding, cross-lamination, wavy bedding, lenticular bedding, parallel bedding, and horizontal lamination), which are commonly found in reverse and bi-gradational sedimentary sequences at various scales. Thirdly, internal erosive surfaces are widely developed, which reflect the fluid winnowing and velocity fluctuations. Fourthly, these contourites are characterised by an abundance of reverse grading and bi-gradational sequences at various scales. In addition, the contourites identified in this study generally lack bioturbational structures, which is probably related to the late migration and radiation of the Ordovician deep-sea benthos. The sedimentary processes, products, and controlling factors of the interacting down- and along-slope currents were further identified, and a bioturbation-free facies model of contourites and a depositional model of the MTCS were established. This study may contribute to establishing the sedimentological criteria for recognition of ancient contourites and a better understanding of the interaction and spatiotemporal evolution of down- and along-slope sedimentary processes, as well as to a deeper comprehension of the Middle Ordovician palaeoceanographical environment in the western margin of the NCC.

Motor control is an important component of animal movement that relies on the nervous system to conduct coordinated locomotion. Marine trace fossils, recording a myriad of movement patterns of principally invertebrate bilaterians, provide unique geological evidences for the evolution of animal locomotor behaviour. Here we report highly geometrical circular trace fossils from the Upper Ordovician deep-water slope deposits of North China. They consist of a small-sized ring-like main burrow with around 8 or 12 regularly-spaced tangential branches, contributing to semi-octagonal or semi-dodecagonal patterns with an average turning angle between successive branches of about 45° and 30°, respectively. The individual specimens also display regular and locally highly symmetric combination patterns like a Venn diagram. The ordered geometric expression of tiny circular trace fossils here suggests a relatively high level of motor control from minute invertebrate animals. Bilaterian motor control evolution in the early Palaeozoic as evidenced by the marine trace fossil record could be a key ingredient of biological evolutions during the Cambrian and Ordovician radiations. The Ordovician Radiation as an ecological expansion in the marine realm was accompanied by distinct offshore migration of the shallow-shelf ichnofauna and compositional change in the deep-sea ichnofauna. The greatly ameliorated deep-sea food content and relatively homogenous deep-sea food distribution may have promoted more geometrical and patterned trace fossils with a high level of motor control in the deep-sea regime during the Late Ordovician. It is speculated that after the latest Ediacaran–early Cambrian that set up the bilaterian behavioural toolkit, the Ordovician and Cretaceous represent two periods with distinct behavioural and motor control evolution of the deep-sea ichnofauna, which were in pace with revolutions in pelagic organic matter circulation during the corresponding periods.

A global Late Devonian ostracod database is constructed, incorporating new materials from South China and Northwest China. Four palaeobiogeographical units (Cathaysia, North America, Europe and peri-Gondwana) are recognized during the Frasnian and five palaeobiogeographical units (Cathaysia, North America, Europe, Siberia and Australia) in the Famennian. Three controlling factors (climatic zonation, geographical isolation and global sea-level changes) are identified to have played roles in shaping the palaeogeographical regionalization of ostracod faunas in the Late Devonian. The ostracod palaeobiogeography in the Frasnian was mainly influenced by climatic zonation, while rapid changes in tectonic configuration in the Famennian drastically altered the global palaeobiogeography of ostracods. The palaeobiogeographical regionalization of ostracod faunas suggests that Laurussia and Gondwana continued to draw near during the Late Devonian, with the first collision occurring in Southern Central Europe in the Famennian. The South China plate drifted northward to the Kazakhstan plate away from the Australian plate, which gradually became isolated during the Famennian Stage.

Late Devonian to Early Carboniferous deep-sea deposits of the western Junggar, NW China contain 21 ichnotaxa: Arenituba verso (Chamberlain), Chondrites cf. intricatus (Brongniart), Chondrites targionii (Brongniart), ? Chondrites isp., Gordia marina Emmons, Halopoa imbricata Torell, Helminthoidichnites isp., Helminthopsis cf. hieroglyphica Wetzel and Bromley, Laevicyclus isp., Lophoctenium comosum Richter, ? Multina isp., Nereites missouriensis (Weller), Phycodes cf. bilix (Ksiązkiewicz), Phycosiphon incertum Fischer-Ooster, ? Phycosiphon isp., Planolites isp., cf. Taenidium , Thalassinoides isp., Zoophycos isp., undetermined short ridges, and undetermined tubular structures. They form three typical ichnoassemblages, i.e. the Helminthopsis–Helminthoidichnites–Arenituba ichnoassemblage characteristic of upper-bathyal, probably hyperpycnal-flow-influenced deposits, Zoophycos–Nereites–Phycosiphon ichnoassemblage in typical slope deposits, and the Phycosiphon–Nereites ichnoassemblage featuring bottom-current-influenced, lower slope or basin floor muddy deposits. They can be ascribed to the Cruziana , Zoophycos , and the Nereites ichnosubfacies respectively. Comparison with contemporaneous deep-water facies (foremost the Kulm facies in Western and Central Europe) reveals significant loss in the western Junggar of otherwise common element Dictyodora liebeana (Geinitz). Combining the global Palaeozoic tectonic evolution, we propose that Dictyodora was probably originated from peri-Gondwana terranes and the larvae/juveniles of Dictyodora producers hadn't migrated to the northern palaeolatitudes (open ocean Kazakhstan “archipelago”) in the Early Carboniferous. The relatively global distribution of the Phycosiphon–Nereites association indicates efficient larval dispersal of their producers. Intensive bioturbation in deposits dominated by the Phycosiphon–Nereites ichnoassemblage implies a high level of food supply at certain stratigraphic levels, most likely related to surface blooms and enhanced plant detritus input. The monsoonal palaeoclimatic model is integrated with the archipelagic palaeogeography to account for the deep-sea ichnofauna in the western Junggar during the Late Devonian to Early Carboniferous. The most important factors include seasonal climatic perturbations, such as monsoon-derived upwelling events and enhanced primary production, and efficient food/nutrients transport in the dotted island scenario.

Conodont faunas from the Wulankeshun section in the northwestern Junggar Basin of Xinjiang, NW China, are characterized by shallow-water assemblages with many endemic taxa. This study presents separate local icriodid and polygnathid conodont zonations for the Lower Member of the Hongguleleng Formation, which can only roughly be correlated with the pelagic “standard zonation”. The basal beds of the Hongguleleng Formation are assigned to a low diverse Icriodus praealternatus ferus n. ssp. Zone, which possibly includes latest Frasnian strata but it continues into the basal Famennian. At present, the Frasnian/Famennian boundary cannot be defined unequivocally by conodonts and there are no obvious Upper Kellwasser equivalents. However, the carbon isotope data are comparable with the Bulongguor Reservoir stratotype, where the top-Frasnian lies within the basal Hongguleleng Formation. In the early Famennian, partly endemic icriodid lineages provide successive Icriodus cornutus , I. stenoancylus junggarensis n. ssp., and I. plurinodosus n. sp. (sub)zones. The basal Famennian is possibly marked by the oldest, endemic species of Neopolygnathus , Neo. huijunae n. sp. It is followed by local Neo. communis communis , “ Polygnathus ” pomeranicus , Po. cf. szulczewskii , and “ Po. ” pseudocommunis n. sp. zones. The new local conodont zonations provide a high biostratigraphic resolution for further future studies. The Wulankeshun shallow-water conodont faunas show restricted similarities with contemporaneous faunas from eastern Europe, Kazakhstan, and Iran. There are a few taxa that were originally described from other distant regions, such as NW Canada and eastern Australia. The local high number of endemic taxa (17 (sub)species, 46%) points to a significant plate tectonic isolation of the Junggar Basin in the early Famennian.

The Frasnian–Famennian (F–F) event may be recognized in various facies areas in South China. In the pelagic cherty basin facies, both Lower and Upper Kellwasser events can seemingly be recognized. In the deeper water carbonate facies, the F–F event level is well controlled in light of conodont biostratigraphy. In the shallow water carbonate and mixed carbonate-shale facies, the F–F boundary may be defined by clear taxonomic distinction in benthic fossils (articulate brachiopods and corals) as well as evidence from minor pelagic fossils. Post-extinction recovery rate of benthic organisms differs in different facies settings and different taxonomic groups. In open shallow water platform to inter-platform depression areas, brachiopods seem to recover quickly, probably in the Middle Pa. triangularis Zone; benthic ostracodes seem to recover at a later stage; recovery of rugose corals did not happen until the uppermost Famennian. Three steps of the F–F mass extinction are postulated: 1) extinction of diverse brachiopods (including most atrypids); 2) extinction of pelagic conodonts; 3) extinction of both benthic faunas (very abundant and diverse rugose corals and ostracodes) and pelagic conodonts. Evidence of an end-Frasnian regression in South China is clear, particularly in shallow water settings. However, in deeper water settings, the picture is complicated, with evidence of both sea level rise and fall in the latest Frasnian. It may be assumed from overall data so far known that crustal evolution itself and associated multiple volcanic/hydrothermal activities may have mainly caused frequent and rapid climatically warming-cooling alterations and sea level changes as well as marine ecologic collapse (eutrophication, microbial blooming, seawater acidification, and anoxia), which may explain the F–F extinction pattern in South China.

Abundant Late Devonian radiolarians occur in the siliceous rocks of the Karamay ophiolitic melange in western Junggar. The siliceous rocks are interpreted as deposit in a remnant oceanic basin in view of their petrological and geochemical characteristics. New data suggest that the age of the Karamay ophiolitic melange can be extended from the Ordovician to Late Devonian, thus representing the youngest known oceanic crust in western Junggar, which indicates that the closure of the Paleo-Asian Ocean was at least after the Late Devonian in southern western Junggar. The Carboniferous formation capping the siliceous rocks units comprises, in ascending order, a broad regressive sequence from the abyssal–bathyal turbidites, littoral-neritic carbonates, and calcareous clastic rocks to molasse, indicating that the ocean–continent transformation probably occurred in the Devonian–Carboniferous transition or the early Early Carboniferous. The oceanic basin was filled with volcaniclastic turbidites in the Visean–Serpukhovian, and evolved into a residual sea basin in the Late Carboniferous. The final closure of the Paleo-Asian Ocean in western Junggar was marked by the emergence of molasse in the late Late Carboniferous.

Continuous centimeter-scale sampling for conodonts with microfacies and carbon isotope analysis has been carried out across the Frasnian–Famennian (F–F) transition at the Yangdi section, Guangxi, South China. The newly revised conodont biostratigraphy reveals a succession of six zones, ranging from the upper Palmatolepis rhenana zone to lower Palmatolepis crepida zone in ascending order. Based on a detailed analysis of conodont abundance and diversity changes through the section, two intervals involving significant conodont faunal changes were recognized in the uppermost Palmatolepis linguiformis zone at the Yangdi section. The first conodont change occurred at the transition between the lower and upper Pa. linguiformis zone and is marked by the disappearance of Pa. linguiformis , accompanied by the successive disappearances of Pa. eureka , Pa. rhenana , Pa. nasuta , Pa. gigas , Ad. ioides , and Ad. nodosa . The second conodont change appeared in a horizon equivalent to the uppermost Upper Kellwasser Horizon (UKH) and is indicated by the elimination of nearly all Frasnian palmatolepids, ancyrodellids, and polygnathids. Furthermore, the second conodont change is coincident with the decimation of ostracods and tentaculitids and is synchronous with the turnovers of conodont biofacies. In addition, the onset of the δ 13 C carb perturbation is a little earlier than the second conodont change, with the maximum amplitude of excursion right at the start of the Famennian. Therefore, we conclude that the second conodont change represents the F–F mass extinction based on the temporal correlation among δ 13 C carb excursions, pelagic faunal changes, and conodont biofacies turnovers during the F–F boundary interval. According to the high-resolution conodont biostratigraphy together with cyclostratigraphy, the uppermost UKH and whole UKH contain 1 and 12 bundle cycles, respectively. Thus, the time span of the mass extinction and the entire Upper Kellwasser crisis lasted 16–18 kyr and ~ 200 kyr, respectively.

Two sections of the Late Devonian to Early Carboniferous Hongguleleng Formation in the Sha'erbuerti and Xiemisitai mountains of western Junggar, NW China were logged in detail and studied with particular reference to their trace fossil content and sedimentary features. The Hongguleleng Formation is composed essentially of shallow marine deposits formed in a volcanic arc-related setting. It contains trace fossils including indeterminate ellipsoid structures, indeterminate shallow-pit structures, Chondrites intricatus, Chondrites targionii, Chondrites isp., Dolopichnus gulosus,?Multina isp., Nereites missouriensis, Nereites isp., Palaeophycus tubularis, ?Phycosiphon isp., ?Phymatoderma isp., Rhizocorallium commune, Rosselia cf. socialis, Teichichnus rectus, Teichichnus ispp., Thalassinoides isp., and Zoophycos ispp. These ichnofossils and related bioturbation structures constitute five distinct groups of ichnofabrics: Chondrites–?Phymatoderma, Rhizocorallium commune, anemone dwelling/burrowing, Teichichnus, and Zoophycos ichnofabrics, conforming to an upward trend from the Cruziana to Zoophycos ichnofacies. The volcanic arc setting provides a natural laboratory to investigate the colonisation styles of benthic faunas during the Devonian, especially for environments with widespread and relatively frequent depositional events disturbing background deposition. The distal event beds are especially suitable for the distinction of the relationship between background and post-event ichnofaunas. Simple and composite ichnofabrics have been distinguished. The simple ichnofabrics are typified by the indeterminate ellipsoid “ichnofabric” made by sea anemones, representing short colonisation event and in situ death and burial resulted from relatively high sedimentation rates even during the periods between volcanic explosions. The composite ichnofabrics are characterised by the Chondrites–?Phymatoderma, ?Multina–Zoophycos and multi-tier Zoophycos ichnofabrics, representing vertical migration of benthic faunas in pace with either distal event deposition or steadily accreted sea floor. The colonisation window in the arc-related setting is closely related to sedimentation rates and frequency of depositional events, determining the completeness of burrow system structure and maturity of benthic communities.

To date, 37 species and 2 subspecies (36 species plus 1 species that with 2 subspecies) of the ostracode genus Cribroconcha Cooper, 1941 have been reported worldwide, ranging in age from the Middle Devonian to the Early Permian with an acme during the Carboniferous. Based on the geographical distribution and morphological characteristics of Cribroconcha, two evolutionary lineages (i.e., Lineage 1 and Lineage 2) are identified, which originated in the European and the Kazakhstan plates, respectively. Lineage 1 can be subdivided into three types: 1-A (stable type), 1-B (reshaped type) and 1-C (spiny type). Lineage 2 has a simpler pattern of evolution compared to Lineage 1. Although there were certain accompanying changes in the morphology of carapaces, the general pattern and most successful evolutionary novelty of Cribroconcha appears to be the appearance of spiny forms in the Early Carboniferous, which continued to be preserved until the Early Permian. The habitats of Cribroconcha may have changed from shallow, warm waters to deep, calm and colder waters in the basinal environments. Four Cribroconcha biozones, extending from the Givetian Stage to Serpukhovian Stage are established in the Euramerica plate, namely C. beckmanni Zone, C. triquetra triquetra Zone, C. cooperi Zone and C. caneyensis Zone.

Widespread oceanic anoxia has been implicated as a killing mechanism during the end-Permian mass extinction (EPME). A high-resolution investigation of pyrite framboids and bioturbation structures in the Shangsi section of South China has revealed repeated and frequent fluctuations of coupled anoxic/euxinic to dysoxic/oxic episodes in the latest Permian, immediately preceding the EPME. Anoxic bottom waters and interstitial water conditions are documented by the smallest pyrite framboids (3–5 μm) and the absence of bioturbation, and dysoxic bottom waters and anoxic interstitial waters are inferred from larger pyrite framboids (6–10 μm) and the occurrence of Zoophycos. In comparison, oxic conditions for both bottom waters and interstitial waters are revealed by a high bioturbation index (BI = 4) and the occurrence of mid-tier Thalassinoides. Fluctuating pyrite framboid sizes and bioturbation structures suggest that bottom and interstitial oxygen levels were neither fully, nor persistently, anoxic/euxinic before the EPME, and instead recorded frequent periodic fluctuations between anoxic/euxinic and dysoxic/oxic conditions. The paleoceanic redox variation appears to correlate with the 405-ka eccentricity cycles in the anhysteretic remanent magnetization (ARM) series, suggesting that fluctuations might have been controlled by Milankovitch cycles. The role of fluctuations between anoxic/euxinic and dysoxic/oxic episodes in the latest Permian to the EPME is unclear, but it seems plausible that they represent a prelude to the highly stressed conditions that are characteristic of the EPME.

Dictyodora has been generally considered an ichnogenus with a restricted temporal range from the Cambrian to the Mississippian. Until now, there have been no reports of Dictyodora after the Mississippian. Here we report on well-preserved and abundant Dictyodora from deep-sea sediments of the Lopingian Maomaolong Formation in West Qinling, central China, which is hitherto the youngest occurrence of Dictyodora and extends the stratigraphic range of Dictyodora to the Late Permian. Two ichnospecies of Dictyodora are distinguished: D. zimmermanni and D. cf. scotica. Unlike the small-sized Dictyodora in the pre-Pennsylvanian, the three-dimensional morphology of Dictyodora studied here shows larger amplitudes and longer limbs with clearly inclined walls and basal burrows, which are interpreted to have been made by a soft-bodied worm-like organism with a snorkel-like organ as similarly documented in previous studies. Detailed systematic ichnological features and SEM and EDS results indicate that Dictyodora here is not simply a respiration structure made during the locomotion of the trace maker, but resulted from active filling by the trace maker. Dictyodora is probably not a good indicator of the deep-marine environment in the Paleozoic. From our dataset, Dictyodora originated from the shallow-marine environment in the early Cambrian, then migrated into the deep sea in the Ordovician and the marginal-marine setting in the Wenlock, and was finally restricted to the deep-marine environment in the Carboniferous and Permian. Both Psammichnites and Dictyodora are structures made by organisms with snorkel-like organs, and both were eliminated during the end-Permian mass extinction.

The loboliths, which previously have been called “plurilocular cystoids” in China, are actually the bulbous roots of scyphocrinoids, which occur only, and are widely distributed, in the uppermost Silurian through the lowermost Devonian. Two quite different types of loboliths can be distinguished, the plate- and cirrus-types loboliths, both of which are significant fossils for the correlation of the strata at the Silurian–Devonian boundary. Two lobolith-bearing layers were found in pyroclastic turbidites at the Silurian–Devonian transition in western Junggar, Xinjiang, NW China; all identified loboliths are of the plate type. This discovery provides not only important information for determination of the Silurian–Devonian boundary in western Junggar, but also for the stratigraphic correlation outside of peri-Gongwana and Laurussia. Moreover, the finds are expanding the knowledge of the paleogeographic distribution of scyphocrinoids across facies boundaries between the paleocontinents.

The Late Devonian Period was a critical geological interval, affected by numerous significant global bio- and environmental events, including the Kellwasser, annulata and Hangenberg events, and a major climate transition leading to the Carboniferous ice ages. The timing and pattern of these events are unclear due to lack of the precise time scale. In this study, an analysis of calcium concentration series was carried out on the Upper Devonian cyclostratigraphic slope-facies of the Lali section, South China. Objective testing of the section indicates the presence of astronomical forcing: long orbital eccentricity, short eccentricity, obliquity, and precession index. Two independent astrochronologies were developed for the Ca series and compared with spectral analysis. The age of the Devonian–Carboniferous boundary (358.9 ± 0.4 Ma) was selected as an “anchor”, and an Astronomical Time Scale (ATS) was constructed from the late Frasnian to early Tournaisian based on 405-kyr cycles. The ATS indicates a duration of the Famennian Stage of 14.4 ± 0.28 myr, and assigns 373.3 ± 0.49 Ma to the Frasnian–Famennian boundary. The durations of the Famennian conodont zones are also indicated. The timing of Famennian bio- and environmental events also can be established by the ATS. The Upper Kellwasser horizon starts at 373.4 Ma and is constrained to a duration of 100-kyr; a sharp positive carbon isotope excursion CIE, +3‰ recognized across the Frasnian–Famennian boundary lasts 300 kyr. The Lower and Upper annulata events each last 50-kyr with positive CIEs; and the ages of two CIE peaks are 361.7 Ma and 361.3 Ma, respectively. Five transgressive events, including the Nehden, Enkeberg, Dasberg, Strunian, and Hangenberg transgressions occur at 370.6 Ma, 368 Ma, 360.4 Ma, 360.1 Ma, and 358.9 Ma, respectively. Five regressive events i.e., the linguiformis, prima, Condroz, velifer, and Derwer regressions occur at 373.4 Ma, 371 Ma, 369 Ma, 362.3 Ma, and 359.2 Ma, respectively.

Large numbers of densely distributed Rhizocorallium provide a window to understanding the behavioural and functional changes of the trace maker after extreme environmental events. This study focuses on the analysis of Rhizocorallium from the Middle Triassic (Anisian) limestones in the Boyun section, Yunnan Province, Southwest China to investigate the ecological strategies and ethological signatures of its producers before and after storm events. Based on its morphological features, the studied Rhizocorallium is attributed to two ichnospecies Rhizocorallium jenense and R. commune, the latter showing two varieties R. commune var. auriforme and R. commune var. irregulare. In addition to Rhizocorallium, the trace fossil assemblage consists of Arenicolites, Palaeophycus, Planolites and Thalassinoides, which allows assignation to the Cruziana ichnofacies associated with the shallow marine environment. The studied ichnofossil-bearing intervals in the Boyun section are usually high bioturbated, with BPBI (bedding plane bioturbation index) around 5. The ichnoassemblage has a relatively low ichnodiversity and shows high density of Rhizocorallium, which is interpreted as the result of the opportunist strategy when the Rhizocorallium trace makers exploited the quiet, nutrient-rich substrates after storm events. Crosscutting relationships between multiple levels of Rhizocorallium indicate that earlier burrows were reworked by later ones due to successive storm events and erosion of the shallow-tier burrows. Orientation of the marginal tubes of Rhizocorallium jenense shows a bidirectional pattern at 295°NW and 160°SE, which may record the changes of the main flow direction. Diameter measurements support the total recovery of the macrobenthic trace makers during the Middle Triassic (Anisian).

Forty-eight ostracod species belonging to 28 genera from the Late Devonian of Guangxi in South China are described and figured. The ostracod assemblage from the Nandong section can be attributed to the rhenana–linguiformis conodont zones. The ecological assemblages of ostracods from the Yangdi section correspond to a smooth-podocopid association accompanied by some pelagic entomozoids. This mixed assemblage is indicative of an environment of carbonate platform to slope during an ongoing regression. The ostracod faunas from the Nandong section are on the contrary composed of both pelagic and benthic ostracods and pelagic forms dominate in number of specimens suggesting a basin environment.

We present a new biostratigraphically constrained carbon isotope record from the Lali section (South China) to document perturbations in the Late Devonian carbon cycle. Positive carbon isotope excursions (CIEs) are most important components of the Late Devonian long-term carbon isotope cycle: Frasnes (+2‰), Middlesex (+1‰), Lower Kellwasser (+3‰), Upper Kellwasser (+3‰) and Upper annulata (+1‰) events, as well as a small positive CIE (+1‰) in the Famennian expansa-aculeatus zones were recorded. It is noteworthy that no significant carbon isotope shifts are found for the Rhinestreet, Nehden, Condroz and Enkeberg events. The Late Devonian long-term carbon isotope curve from South China is in agreement with contemporaneous world-wide trends in Euramerica (Europe and North America) and Gondwana. Global data suggests a higher Famennian δ13Ccarb baseline (about +2.5 ‰) than that of the Frasnian (about +1‰). Previous studies have related the positive CIE to ocean anoxia, but its ultimate driver remains unclear. Other interpretations include the spread of land plants or increased tectonic activity, but these explanations are questionable due to the relative short durations of the CIEs compared to long-term processes of plant evolution and plant cover extension as well as tectonic movements.

The Lali section (Guangxi Province, South China) is composed of quiet-water carbonates containing abundant conodonts, which allowed recognition of 12 Frasnian and 20 Famennian biozones. The Kellwasser and annulata events are characterized by transgressive black carbonates, while the Hangenberg Event is represented by black shale deposits. Other transgressive events recognized at Lali include the Middlesex, Nehden, Enkeberg, and Dasberg, as well as the Strunian transgression. Four regressive events were recognized on the basis of lithological and microfacies changes, i.e., the linguiformis regression, Condroz Event, velifer regression, and the Derwer regression. These sea-level change events were of short duration and globally isochronous based on conodont correlations. Microfacies analyses and the abundance of Palmatolepis indicate that the highest Frasnian sea level lies in FZ 12-13 (Upper rhenana Zone), whereas the highest Famennian sea level was in the utahensis Zone.

Givetian, Frasnian and Famennian limestones from southern China contain microfossils generally regarded as calcified algae and cyanobacteria. These are present in 61 out of 253 sampled horizons in four sections from three widely spaced localities in Guangxi and southern Guizhou. Three of the sections sampled are Givetian-Frasnian-Famennian; one section is Frasnian-Famennian. They include reef and non-reef carbonates of shallow marine platform facies. The following taxa are identified with differing degrees of confidence, and placed in algae, cyanobacteria or microproblematica. Algae: Halysis, ‘solenoporaceans’, Vermiporella. Cyanobacteria: Bevocastria, Girvanella, Hedstroemia, Subtifloria. Microproblematica: ?Chabakovia, Garwoodia, ?Issinella, Izhella, Paraepiphyton, Rothpletzella, Shuguria, ?Stenophycus, Tharama, Wetheredella. As a whole, the abundance of algae, cyanobacteria and microproblematica increases by 34% from Givetian to Frasnian, and declines by 63% in the Famennian. This secular pattern of marked Famennian decrease does not support recognition of them as “disaster forms” in the immediate aftermath of late Frasnian extinction. Nonetheless, their survival into the Famennian could indicate tolerance of environmental stress, independence of changes in food supply, morphologic plasticity, and ability to occupy a range of habitats and depths. Uncertainties concerning the affinities of the problematic taxa hinder assessment of their significance.

Song, J., Crasquin, S. & Gong, Y., September 2016. Ostracods of the Late Devonian Frasnian/Famennian transition from western Junggar, Xinjiang, NW China. Alcheringa 41, xxx–xxx. ISSN 0311-5518.Ostracods are described for the first time from the Late Devonian of western Junggar in Xinjiang, NW China. Fifty-two species belonging to 30 genera are recognized, and seven are new: Arcuaria hebukesarensis sp. nov., Bairdia shaerbuertiensis sp. nov., Cribroconcha honggulelengensis sp. nov., Microchelinella bulongourensis sp. nov., M. hoxtolgayensis sp. nov., Pribylites wulankeshunensis sp. nov. and P. junggarensis sp. nov. The ostracod fauna indicates a probable late Frasnian age for the lower member of the Hongguleleng Formation, and the Frasnian/Famennian boundary may exist in the basal part of the formation. The ostracod assemblages are referable to the Eifelian Mega-Assemblage, incorporating both the palaeocopid and smooth-podocopid associations. The fauna implies deposition in a nearshore–offshore environment...