The research expanded our understanding of the morphological diversity and geographical distribution of mixopterids. Eurypterids (Arthropoda: Chelicerata), normally known as sea scorpions, are an important extinct group of Paleozoic chelicerate arthropods. As a star animal in the Silurian sea (about 430 million years ago), its evolutionary history and paleoecological significance have always attracted attentions of both researchers and the public. Mixopterids are a remarkable group of eurypterids characterized by extremely specialized prosomal appendages. These limbs were presumably used for prey-capture, like the ‘catching basket’ formed by the spiny pedipalps of whip spiders. However, in contrast to their popularity, our knowledge of these bizarre animals is limited to only four species in two genera which all based on a few fossil specimens from the Silurian Laurussia 80 years ago. Recently, postgraduate WANG Han, Prof. WANG Bo and other researchers from China, German and England described a new mixopterid, Terropterus xiushanensis gen. et sp. nov. from the Lower Silurian of South China. Their finding represents the first mixopterids in Gondwana, and also the oldest mixopterids. The research expanded our understanding of the morphological diversity and geographical distribution of mixopterids. The research results were recently published as a cover paper in the international academic journal Science Bulletin. Terropterus is relatively large, estimated to have been nearly a meter in length. It bears particularly enlarged prosomal limb III, characterized by a unique arrangement of spines on it. The well-preserved appendages and other body parts fossils provided new evidences for expanding morphological diversity of Mixopteridae. By morphological comparison and phylogenetic analysis, researchers suggested more complex evolutionary relationships of this group than previously thought. Terropterus, a large arthropod with "sharp weapon", may have been playing an important role of top predators in Early Silurian shallow marine of South China. Meanwhile, the first Gondwanan mixopterid- along with other eurypterids from China and some undescribed specimens- suggests an under-collecting bias in this group. Future work, especially in Asia, may reveal a more cosmopolitan distribution of mixopterids and perhaps other groups of eurypterids. This research was supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China. Mr. YANG Dinghua (from NIGPAS) made the artist’s reconstruction. Reference: Wang Han *, Dunlop J., Gai Zhikun, Lei Xiaojie, Jarzembowski E. A., Wang Bo *, First mixopterid eurypterids (Arthropoda: Chelicerata) from the Lower Silurian of South China, Science Bulletin, https://doi.org/10.1016/j.scib.2021.07.019Fig.1 Cover image of Science Bulletin. (Reconstruction drawing by Dinghua Yang) Fig.2 Terropterus xiushanensis. (a, c, d, e, f: appendages; b: reconstruction drawing, dorsal and ventral views; g: genital operculum and the genital appendage) Fig. 3 Result of the phylogenetic analysis. (The position of Terropterus xiushanensis is highlighted in blue) Contact: LIU Yun, PropagandistEmail: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Anthrophyopsis Nathorst 1878 is an extinct but representative Late Triassic gymnosperm genus with uncertain systematic affinities and poorly understood morphology and anatomy. Since its earliest report by Nathorst in 1878, this fossil has been documented worldwide. However, the taxonomic statuses and the leaf morphological variation of this fossil plant remain questionable. Anthrophyopsis Nathorst 1878 is an extinct but representative Late Triassic gymnosperm genus with uncertain systematic affinities and poorly understood morphology and anatomy. Since its earliest report by Nathorst in 1878, this fossil has been documented worldwide. However, the taxonomic statuses and the leaf morphological variation of this fossil plant remain questionable. Recently, an international research team led by Prof. WANG Yongdong (Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science(NIGPAS) ), collaborated with Prof. Mihai E. Popa from University of Bucharest of Romania, and Prof. ZHANG Tingshan’s team (Southwest Petroleum University of China), has published a new study in international journal Review of Palaeobotany and Palynology. In this research, we carried out a comprehensive systematic study of Anthrophyopsis and investigated the significance of its tempo-spatial distribution pattern. The team collected several well-preserved fossil material belonging to Anthrophyopsis from the Upper Triassic Xujiahe Formation in Guangyuan City of northern Sichuan Basin, South China. The newly collected specimens show leaves with incisions which even can generate a unipinnate leaf architecture (Figs. 1, 2). Wang says, “these specimens show various outlines with depths of incision for different leaves, pointing to transitional shapes between entire and lobed margins.” This enables a detailed and updated morphological diagnosis emendation of this fossil at genus and species level. Based on this, a new reconstruction of its type species Anthrophyopsis crassinervis was carried out with emphasis of its heteromorphic leaf morphologies (Fig. 3). The re-investigation on the global fossil record shows that among 16 species of Anthrophyopsis documented worldwide, only three of them are valid species (including Anthrophyopsis crassinervis, A. tuberculata and A. venulosa). Other four species need further revision, and nine species are invalid. In addition, Anthrophyopsis has a short stratigraphic range and confined to Upper Triassic sequences, from the Carnian to the Rhaetian, and it has a distinct stratigraphic significance. Anthrophyopsis possibly originated from the South China Block during the Carnian, migrated along the northern frame of the Tethys realm, and finally arrived in Middle East and Europe. The short stratigraphic range of Anthrophyopsis in the Southern Floristic Province (SFP) implies a climate differentiation between the SFP and the Northern Floristic Province (NFP) during the Late Triassic (Fig.4). The limited occurrences of valid Anthrophyopsis species in the Southern Floristic Province of China during the Late Triassic indicate that this genus represents a sensitive stratigraphic and palaeoclimatic marker. This study was co-sponsored by the National Natural Science Foundation of China, Strategic Priority Research Program (B) of the Chinese Academy of Sciences and the State Key Laboratory of Palaeobiology and Stratigraphy. Reference: Xu Yuanyuan, Mihai E. Popa*, Zhang Tingshan, Lu Ning, Zeng Jianli, Zhang Xiaoqing, Li Liqin, Wang Yongdong*, 2021. Re–appraisal of Anthrophyopsis (Gymnospermae): New material from China and global fossil records. Review of Palaeobotany and Palynology, 292(3): 104475. DOI: 10.1016/j.revpalbo.2021.104475. Fig.1 Anthrophyopsis crassinervis from Guangyuan area of northern Sichuan Basin, South China, showing showing almost entire margin with crenation Fig.2 Anthrophyopsis crassinervis from Guangyuan area of northern Sichuan Basin, South China, showing thick midrib with secondary vein meshes and leaf margin with deep incisions
Fig. 4 Palaeogeographic map showing the distribution of genus Anthrophyopsis around the world during the Late Triassic and its suggested migration routes. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The western Liaoning region is known as one of the most significant fossil localities for the Jurassic osmundaceous rhizome remains in the Northern Hemisphere. Recently, a new species of osmundaceous rhizome, Claytosmunda zhangiana sp. nov. was reported with associated fungal remains represented by fungal hyphae in this spectacular osmundaceous rhizome. The research team led by Prof. WANG Yongdong (Nanjing Institute of Geology and Palaeontology, CAS), Dr. TIAN Ning (Shenyang Normal University), and Dr. JIANG Zikun (Chinese Academy of Geological Sciences) has carried out a systematic study on a structurally preserved permineralized osmundaceous rhizomes from the Jurassic of western Liaoning. This new finding results were published in the international journal Review of Palaeobotany and Palynology. The results not only further enriches the record of fossil diversity of Mesozoic osmundaceous rhizomes in China, but also contributes to further understanding the evolution of plant–fungal interactions in the Jurassic forest understorey ecosystem. The fossil material was collected from the Middle Jurassic Tiaojishan Formation in western Liaoning Province, NE China, ca. 160 Ma. Prof. WANG says, “the fossil specimen is represented by a rhizomatous stem consisting of a pith, a dictyoxylic siphonostele, a two-layered cortex, and a mantle of petiole bases”. A remarkably specialized heterogeneous petiolar sclerotic ring, whose abaxial side is occupied by a dumbbell-shaped thick-walled fiber arch, characterizes this new fossil species. This results helps for exploring the anatomical diversity of petiolar sclerotic rings of the Mesozoic and extant osmundaceous plants. Additionally, five major types of petiolar sclerotic rings are recognized. Specifically, the fungal remains, represented by branched hyphae and a kind of saprophytes, are found within the fern rhizome. This represents the first report of fungal remains associated with osmundaceous rhizomes in China. This study was jointly supported by National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the CAS, the Liaoning Revitalization Talents Program, and the State Key Laboratory of Palaeobiology and Stratigraphy (NIGPAS, CAS). Reference: Tian, N.*, Wang, Y.D.*, Jiang, Z.K., 2021. A new permineralized osmundaceous rhizome with fungal remains from the Jurassic of western Liaoning, NE China. Review of Palaeobotany and Palynology, 290: 104414. Doi: 10.1016/j.revpalbo.2021.104414 (*corresponding author).
Fig.1 Claytosmunda zhangiana sp. nov. from the Middle Jurassic of western Liaoning Province, NE China Fig.2 Anatomical details of the petiole bases of Claytosmunda zhangiana sp. nov. Fig.3 Sketch drawing of the petiole bases of Claytosmunda zhangiana sp. nov. Fig.4 Fungal hyphae found within the permineralized osmundaceous rhizome
The late Neoproterozoic to the Early Cambrian is a key turning point in the evolution of the earth's environment and life. Great changes have taken place in the whole biosphere, atmosphere and hydrosphere. After the Neoproterozoic Glaciation, the sulfur isotope of seawater sulfate showed the largest positive anomaly in geological history. The values of δ34S fluctuates between 30‰ and 35‰, and sometimes even reach 45‰. This phenomenon was first discovered in Yudomski Formation in Siberia, which is called Yudomski Event. During this period, the sulfur isotope of sulfate in seawater changed dramatically, and its process was also recorded by sulfate deposition, the huge evaporite belt extended from Oman in the Middle East to Iran, Pakistan, northern India, and even to Sichuan Basin. Recently, MENG Fanwei, Associate Professor of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), cooperated with Professor Krzysztof Bukowski of AGH University of technology in Poland and Professor Naveed Ahsan of Punjab University in Pakistan to continuously analyze the gypsum deposition of Salt Range Formation from late Neoproterozoic to Early Cambrian in Salt Range area in northern Pakistan of India plate, The abnormal event was first found in the strata in northern Pakistan, which is also the first systematic study of the event in Pakistan. The research results were recently published in the European academic journal Geological Quarterly. It is found that the sulfur isotope of gypsum in Salt Range Formation ranges from 35‰ to 30‰ from Late Proterozoic to Early Cambrian, and gradually decreases to about 30‰ with the formation from bottom to top. The same sulfur isotope anomaly has been found in Tarim Basin, northwestern China, which supports this previous speculation about the affinity between the Indian plate and the Tarim Basin. The study of sulfur isotopes of evaporites in Salt Range area in northern Pakistan of the Indian plate not only reveals that the global consistency of the Yudomski event, but also for the correlation of evaporite stratigraphy within the globe and the recovery of world paleogeography, as well as the sources of hydrocarbon sources formed at the same time. This study is also a report of the results of the investigation of salt range and other areas in northern Pakistan by NIGPAS from February 21 to March 6, 2018.This work was financially supported by the National Natural Science Foundation of China, the Basic Frontier Scientific Research Program of the Chinese Academy of Sciences, AGH University of Science and Technology and by the Bureau of International Co-operation, Chinese Academy of Sciences. Reference: Fanwei Meng, Zhili Zhang, Krzysztof Bukowski*, Qingong Zhuo, Naveed Ahsan, Saif Ur-Rehman and Pei Ni, 2021. A strongly positive sulphur isotopic shift in late Ediacaran-early Cambrian seawater: evidence from evaporites in the Salt Range Formation, north ern Pakistan. Geological Quarterly, 65: 30. http://dx.doi.org/10.7306/gq.1598. Fig, 1 Gypsum in Salt Range Formation, northern Pakistan Fig. 2 The sulfur isotope data of gypsum in Salt Range Formation
How did the camouflage skills of insects originate and evolve? The new reports of mantle behavior in two major groups of insects (the rodent and hemiptera toadstool families) in the Mesozoic advance the record of their mantle behavior to before the great radiation of flowering plants. How did the camouflage skills of insects originate and evolve? The new reports of mantle behavior in two major groups of insects (the rodent and hemiptera toadstool families) in the Mesozoic advance the record of their mantle behavior to before the great radiation of flowering plants. Animals have evolved several strategies in prey-predator interactions due to selective pressures, such as mimicry and camouflage. Both mimicry and camouflage enable animals to effectively reduce the probability of detection by prey and predators. As the most diverse animal group, insects have evolved such strategies through various pathways including utilizing specialized morphologies. Plant-like mimesis and debris-carrying camouflage are rather common adaptations within insects. Plant-like mimesis, an effective way to hide by mimicking leaves, sticks or bark, is rife among resting katydids, walking sticks and leaf insects. Debris-carrying camouflage is most common in Neuroptera and Hemiptera, in which larvae match their life-supporting environment by decorating themselves with exogenous debris. Although several fossil insects have been reported showing plant-like mimesis and debris-carrying camouflage from the Mesozoic, the abundance of taxa involved is much rarer than in modern groups, and more investigation is needed. Recently, Mr. XU Chunpeng, supervised by Prof. WANG Bo from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), cooperated with researchers from Wuhan University and University of Kansas, have reported a pygmy mole cricket (Tridactylidae) mimicking spike mosses or leafy liverworts from mid-Cretaceous Kachin amber (approximately 99 million years ago). The behavioural mimicry interpretation is further confirmed by Siamese Neural Network analysis. Additionally, the research reported a diverse insect assemblage with debris-carrying camouflage from mid-Cretaceous Kachin amber, comprising six nymphs of Psocodea and a nymph of Gelastocoridae. These researches have been published on Gondwana Research and Historical Biology. The new find pygmy mole cricket Phyllotridactylus wangi displays mimicry with some coeval spike mosses or leafy liverworts which are spore-bearing plants and quite diverse in mid-Cretaceous Kachin amber. Phyllotridactylus wangi exhibits a morphological resemblance to these leafy liverworts and spike mosses in gross morphology, including the shape of leaves. The most striking feature is the remarkable inflation of the metafemur, which resembles leaf lobes of some spike mosses laterally or dorsolaterally. Additionally, the inflation made by the mesofemur and mesotibia also resembles the central “leaflets” of spike mosses or leafy liverworts. Critically, Mesozoic plant mimesis in Tridactylidae is supported by Siamese Network analysis. In order to analyze the resemblance of P. wangi with model plants, the researchers developed a new approach to utilize the Siamese Network of Deep Learning, which can measure the dissimilarity between two images by calculating the “distance” between image pairs and provide a dissimilarity value. The deep learning algorithms are used to quantify the mimicry of fossil insects in this study for the first time, providing a new model for quantifying the mimesis of fossil insects and novel insights into exploring the early evolution of mimicry. "After pre-training the Siamese Network by part of TLL (a similar image dataset) and fine-tuning it by part of LIMD (a dataset contains image pairs of extant insects and their model mimicry plants), the remainder part of LIMD is input and a dissimilarity threshold value of mimic definition for extant insects is calculated" , Prof. WANG Bo says, "we fine-tuned the dissimilarity threshold value of mimic definition for extant insects based on the FIMD (a dataset contains image pairs of fossil insects and their model mimicry plants), and calculated the dissimilarity threshold value of mimic definition for fossil insects". Among these specimens, six nymphs of Psocodea and a nymph of Gelastocoridae exhibit debris-carrying behaviour. Psocodean nymphs are belonged to three Morphotypes, which might stick sand and organic material with their setae on their backs. Gelastocorid nymph shows a very flat form, being both dorsally and ventrally covered with unequal-sized sand grains and plant debris. It has a flat abdominal tergum forming a defined space for the trash packet components, which can facilitate carrying debris more stably on the dorsal surface. These finds are the oldest fossil records of Psocodea and Gelastocoridae with debris-carrying camouflage, extending the geological range of this behaviour within Psocodea and Gelastocoridae by approximately 80 million years. Together with previously known records, these fossils demonstrate that most extant debris-carrying insects (eight groups with direct camouflage) had evolved exogenous camouflage by the mid-Cretaceous. Mimicry and camouflage are important in insects to avoid detection by both prey and predators. By the Cretaceous, many new predaceous arthropods (including some spiders, lacewing larvae, and ants) and vertebrates (including lizards, birds, and mammals) were present. These results suggest that elaborate mimicry and camouflage were already widespread among insects in the mid-Cretaceous ecosystems during the rise of angiosperms, probably responding to similar selective pressures as those experienced by their extant counterparts. We thank WANG Ning and GE Chang for kindly providing the specimens, and YANG Dinghua for reconstructions of fossil specimens.
References: Xu, C., Wang, B., Fan, L., Jarzembowski, E.A., Fang, Y., Wang, H., Li, T., Zhuo, D., Ding, M., Engel, M.S. (2021). Widespread mimicry and camouflage among mid-Cretaceous insects. Gondwana Research. https://doi.org/10.1016/j.gr.2021.07.025. Fan, L., Xu, C., Jarzembowski, E. A., Cui, X. (2021). Quantifying plant mimesis in fossil insects using deep learning. Historical Biology, 1-10. https://doi.org/10.1080/08912963.2021.1952199. Figure 1: Pygmy mole cricket Phyllotridactylus wangi gen. et sp. nov. (b, d, f) and potential model plants (a, c, e, g) from mid-Cretaceous Kachin amber. Figure 2: Psocodean nymphs (a–f) and gelastocorid nymph (g, h) from mid-Cretaceous Kachin amber. Figure 3: Geological range of insect groups that display plant mimesis and debris-carrying camouflage behaviour. Figure 4: Ecological reconstruction of gelastocorid nymphs and a tridactylid. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Well-developed Devonian deposits are widely spread in west and east marginal areas of the Junggar Basin, North Xinjiang, which acts are representative areas of Devonian flora of North China. The Devonian strata of the eastern and western sides of the Junggar Basin belong to different palaeoblocks paleogeographically, and scholars have been conducting more in-depth studies on plant fossils of the West Jungga.However, few knowledge of plant fossils from the Devonian of East Junggar hinders understanding to its flora and further comparison. Hence, it is necessary to carry on stratigraphical and palaeotological study to the Devonian of East Junggar, for the significances of early land plant evolution and palaeogeography. Recently, the Devonian Investigation Group (DIG) of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe, conducted a systematic palaeontological study based on materials from the Upper Devonian of East Junggar, Fuyun, Xinjiang. The related research results were published online in the international journal Review of Palaeobotany and Palynology. In this study, the lycopsid Gilboaphyton (Protolepidodendrales) is discovered as a new species. Gilboaphyton fuyunensis, which is characterized by pseudo-spirally longitudinal–hexagonal to fusiform leaf base, slender and entirely marginal leaf with two lateral up turned segments occurring at its one third portion from the base. Using palynological result the study dated and correlated the plant fossil-bearing strata. The research also visualized the spatio-temporal distribution pattern of Gilboaphyton base on its global occurrence data. It is suggested that Gilboaphyton was probably originated in southeastern Laurentia in the Early-Middle Devonian, and spread to the Siberia and Gondwana blocks towards northeast and southwest respectively in the Late Devonian to Early Carboniferous. The similar spatio-temporal distribution of Gilboaphyton and Archaeosigillaria suggest that the two genera might belong to the same plant. Reference: Bing-Cai Liu, Jiao Bai, Yao Wang, Ning Yang, Hong-He Xu *, 2021. On the discovery of Gilboaphyton (Lycopsida) from the Upper Devonian of East Junggar, Xinjiang, and its global distribution. Review of Palaeobotany and Palynology. 292, 104473. https://doi.org/10.1016/j.revpalbo.2021.104473. Fig 1. Fieldwork photo of Devonian investigation Group NIGP-CAS fieldwork in East Junggar, Xinjiang Fig 2. Gilboaphyton fuyunensis Liu et Xu and spores from the Upper Devonian Kaxiweng Formation, Fuyun, Xinjiang, China. Fig 3. Occurrences of Gilboaphyton (pink disks) and Archaeosigillaria (yellow disks) species plotted on the Early-Middle Devonian (A) and Late Devonian–Early Carboniferous (B) palaeogeographic maps.
The oil shale of the Tongchuan Formation has high potential for oil production. The results of this analysis also provide an important basis for the formation and preservation environment restoration of the oil shale of the Tongchuan Formation, and the related research results have been recently published in the international journal Geological Journal. The oil shale of the Tongchuan Formation has high potential for oil production. The results of this analysis also provide an important basis for the formation and preservation environment restoration of the oil shale of the Tongchuan Formation, and the related research results have been recently published in the international journal Geological Journal. The Ordos Basin is the second largest sedimentary basin in China, located in the western part of the North China Craton. The Tongchuan and Yanchang formations are two dominant sedimentary sequences in the Ordos Basin, occurring in the Middle Triassic and Upper Triassic series, respectively. The organic-rich shales in the Yanchang Formation have been considered to be the main hydrocarbon source rock in the Ordos Basin, a great deal of research works have been done on its sedimentary environment. Similarly, thick organic-rich shales are also developed in the Middle Triassic Tongchuan Formation, which immediately underlies the Upper Triassic Yanchang Formation. The earliest known appearance of a Mesozoic-type of tropical, multi-levelled lacustrine ecosystem is also reported from these shales. Up till now, studies of the depositional environment of the Tongchuan shales have been lacking, although it is of significance for understanding the formation and preservation of organic-rich shales and lacustrine fossils. Recently, the research team led by Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) carried out a systematic studies focused on high-resolution carbon (δ13Corg) and sulphur (δ34Spy) isotope analysis as well as undertook total organic carbon (TOC)/pyrite contents and pyrite morphology investigation, and framboidal pyrite size measurements in Tongchuan Formation shales of the Bawangzhuang section of the southern Ordos Basin. Remarkably high TOC (23 ± 9%) and pyrite (7 ± 3%) contents were obtained from the shales, which indicate a large amount of organic carbon and pyrite burial and high primary productivityduring shale deposition. These TOC values are even higher than those from the Yanchang Formation (6%–14%), indicating the Middle Triassic Tongchuan Formation also have high oil-generating potential. And the low varying δ13Corg values (31.8‰ to 28.1‰; average value of 29.1 ± 0.7‰) in Tongchuan Formation suggest balanced and consistent carbon cycles and the high TOC content is probably produced by abundant photoplankton during shale deposition. Dr. ZHAO Xiangdong say, “framboids are the dominant pyrite morphology in the pyrite crystals and show large and variable mean diameters (7.0 ± 1.7 μm to 14.3 ± 6.8 μm) across the section, indicating oxic–dysoxic bottom water during shale deposition.” δ34Spy with narrow and less variable values, ranging from 4.1‰ to 4.9‰. Integrated with pyrite content and morphological patterns, consistent δ34Spy values probably demonstrate a relatively open environment for the formation of sedimentary pyrite, and thus a shallow chemocline that was quite close to the water-to-sediment interface during shale deposition. Overall, the organic-rich shales of the Tongchuan Formation were probably deposited under oxic–dysoxic bottom-water conditions. Shallow chemocline depth combined with moderately high sedimentation rate and high primary productivity may have played crucial roles in the deposition and formation of the organic-rich shales in the Tongchuan Formation. The shallow chemocline also facilitates the fossil preservation in a lacustrine environment. Relevant research work was jointly funded by the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the China National Petroleum Company. Reference: Zhao, X., Wang, W., Xie, G., Pan, S., Jarzembowski, E. A., & Zheng, D. (2021). Depositional environment of Middle Triassic organic-rich shales in the Ordos Basin, Northwest China. Geological Journal, 1–12. https://doi.org/10.1002/gj.4215 Figure 1: Field photographs of the Bawangzhaung section. Figure 2: Petrographic photographs of the Bawangzhuang section. Figure 3: Geochemical profiles at the Bawangzhuang section. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The establishment of Global Standard Stratotype-section and Point (GSSP), i.e. the ‘Golden Spike’, forms the cornerstone of Phanerozoic subdivision and correlation of global chronostratigraphy, and compose common scientific language for exploring Earth history and life evolution, which has great scientific significance for the Stratigraphy and Palaeontology. The GSSP for the base of the Carboniferous System was accepted and ratified by IUGS in February 1990, and is defined by the first appearance of the conodont Siphonodella sulcata at La Serre near Cabrie`res, southern France. Two auxiliary stratotype sections, including the Hasselbachtal section in Germany and the Nanbiancun section in South China, were established to better constrain the Devonian-Carboniferous boundary (DCB) around the world. Nevertheless, since the proposal of the GSSP, the choice of La Serre has received criticism due to unfavourable lithofacies and lack of a “true” phylogenetic transition from Si. praesulcata to Si. sulcata. Meanwhile, there are many difficulties in distinguishing the index conodont Si. sulcata from its ancestor, Si. praesulcata, owing to the existence of abundant transitional forms and morphotypes. As a result, the ICS established a task group to redefine the DCB GSSP. In 2016 Montpellier DCB workshop, a new criterion “base of the Protognathodus kockeli Zone, beginning of radiation and top of major regression (top of the Hangenberg Sandstone event) and end of mass extinction” has been proposed by the task group, which need to be tested for global correlation. Drs. Markus Aretz and Corradini, the chair and vice-chair of the GSSP redefinition work group, organized a special issue (entitled as the “Global review of the Devonian-Carboniferous Boundary”) recently in Palaeobiodiversity and Palaeoenvironments, aiming to provide newest overviews of DCB intervals in important regions (e.g. western Europe, North America and South China etc.), and check the suitability of the proposed boundary level all over the world. In this new paper, we not only briefly review the research history, current status and achievement of DCB in China, but also illustrate representative DCB sections in South China, western Junggar and Tibet. Furthermore, we test the “Montpellier criterion” for the Devonian-Carboniferous boundary redefinition. In South China, there exist numerous well-preserved and continuous Devonian-Carboniferous boundary successions that were formed in low-latitude passive margin basin, and this presents a unique opportunity to decipher the strata along a proximal to basinal transect using integrated biostratigraphical, event-stratigraphical, and geochemical approaches. Our geochemical data (δ13Ccarb, δ15Nbulk, δ238U and Mo/U enrichments, I/Ca ratio) indicated local and global C-N cycling perturbations and marine anoxia in the main phase of the Hangenberg Crisis interval (Middle Siphonodella praesulcata Zone), which coincided with a major regression in South China. Stromatoporoid biostromes and most typical Devonian faunas did not survive into the interval, and the deep-water black shales yield only opportunistic survivors, such as ammonoid Postclymenia cf. evoluta and bivalve Guerichina, along with miospores belonging to the LN Zone. The upper Hangenberg Crisis interval (Upper Si. praesulcata Zone, equal to the Protognathodus kockeli Zone) is marked by initial post-glacial transgression, a global δ13Ccarb spike, and opportunistic faunal blooms, coincident with conodont biofacies shift to the polygnathid-protognathodid biofacies. The Protognathodus fauna, nearly absent from platform facies, is often found in the condensed upper crisis interval of the basin, slope, and platform margin facies within the Youjiang Basin, although the abundance is extremely low and the phylogenetic lineage of Pr. meischneri-Pr. collinsoni-Pr. kockeli cannot be recognized in most successions. In South China, the first occurrence of Pr. kockeli seems to correspond to lithofacies changes, recorded in the first level of transgression just above the Hangenberg Sandstone event. Multiple lines of evidence, including great spatial heterogeneity of δ13Ccarb and δ15Nbulk records, extremes of redox proxies, and lack of macrofossils, suggest that marine habitats remained in a critical/turbulent state during the Upper Si. praesulcata Zone, triggering the opportunistic blooms and minor extinctions. Reference: For detailed information about this paper, please check: Qie, W., Sun, Y., Guo, W., Nie, T., Chen, B., Song, J., Liang, K., Yin, B., Han, S., Chang, J., Wang, X., 2021. Devonian-Carboniferous boundary in China. Palaeobiodiversity and Palaeoenvironments 101, 589-611. https://doi.org/10.1007/s12549-021-00494-z (Note: Springer offers free access till of 18th of August, 2021) For detailed information about the updated DCB special issue, please check: Aretz M., Corradini C., 2021. Global review of the Devonian-Carboniferous Boundary. Palaeobiodiversity and Palaeoenvironments, 101 (2).
Figure 1. A) Palaeogeography locations of Chinese plates during the Late Devonian, paleogeographic maps are from Ron Blakey (www2.nau.edu/rcb7) and B) Tectonic-stratigraphic regions of the Devonian and well-known Devonian-Carboniferous boundary sections in China Figure 2. The international auxiliary stratotype section of the Devonian-Carboniferous boundary at Nanbiancun, Guilin, China. Figure 3. The Muhua II DCB section at Muhua, Changshun, Guizhou. Figure 4. Important shallow-water conodont elements from the DCB intervals in South China characterized by the polygnathid-clydagnathids biofacies of the upper Hangenberg Crisis interval and the endemic siphonodellids biofacies of lower Tournaisian. Figure 5. Stratigraphically important deep-water conodont elements from the DCB intervals in Youjiang Basin, South China characterized by the polygnathid-protognathodid biofacies of the upper Hangenberg Crisis interval and the siphonodellids biofacies of lower Tournaisian Figure 6. Composite geochemical profiles of Devonian-Carboniferous boundary successions in South China.
The mid-Proterozoic (1.85-0.85 Ga) is a critical time for early evolution of eukaryotic organisms. However, this interval has often been referred as the “Boring Billion”, new fossil records will provide some new ideas and basis for the dilemma about the Boring Billion. The mid-Proterozoic (1.85-0.85 Ga) is a critical time for early evolution of eukaryotic organisms. However, this interval has often been referred as the "Boring Billion", new fossil records will provide some new ideas and basis for the dilemma about the Boring Billion. In North China, the Yanshan area represents one of the few geological sites in the world having mid-Proterozoic sedimentary successions with preservation of excellent fossil records, e.g. the oldest eukaryotic fossils recovered from the lower Changcheng Group (ca.1.67~1.63 Ga) (Miao et al., 2019, Precambrian Research), multicellular eukaryotic macrofossils from the Gaoyuzhuang Formation (ca.1.56 Ga) (Zhu et al., 2016, Nature Communications). Recently, an international research group led by Prof. ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) reports a diverse organic-walled microfossil (OWM) assemblage from the shale-dominated Mesoproterozoic Xiamaling Formation (ca. 1.4-1.35 Ga) in the Yanshan area. The study has been recently published on the international academic journal Precambrian Research. The well-preserved OWMs in the assemblage are classified into 36 form species belonging to 28 genera, including 1 new species and 5 unnamed taxa, consisting of various individual vesicles, filamentous microfossils and cellular aggregates (or colonial microfossils). Prof. ZHU says, "most of these taxa are reported for the first time in the Xiamaling Formation". Among them, the researchers inferred 12 taxa with eukaryotic affinity on the basis of the combined characteristics of complex morphology and large cell size. These eukaryotic fossils are predominately spheroidal vesicles with micron-scale surface ornamentations or sculptures (e.g. tubular process, reticulate sculpture, concentric striations, verrucae, outer membrane, equatorial flange), and spheroidal to ellipsoidal vesicles with complex wall structure (e.g. tessellated wall, double-wall construction), and one large tubular taxon Jixiania lineata with longitudinal equidistant striations. According to the researchers, the fossil assemblage shows a moderate eukaryotic diversity which is similar to other contemporaneous OWMs worldwide, demonstrating that the prokaryotes may have still dominated the Mesoproterozoic ecosystems, but eukaryotic life had shown a certain degree of diversification during the Earth's middle age. In addition, Jixiania lineata represents the only taxon in the Xiamaling assemblage with relatively short stratigraphic range, and has been reported from several early Mesoproterozoic successions in Australia, Siberia and Laurentia. The recognition of Jixiania lineata in North China expands its geographic distribution and further enhances its potential as index fossil for early Mesoproterozoic strata. This work was supported by the National Natural Science Foundation of China and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences. Reference: Miao, L., Moczydlowska, M., Zhu, M., 2021. A diverse organic-walled microfossil assemblage from the Mesoproterozoic Xiamaling Formation, North China. Precambrian Research 360, 106235. https://doi.org/10.1016/j.precamres.2021.106235 Fig 1. Taxonomic compositions of the Xiamaling assemblage from the lowermost Xiamaling Formation. Fig2. Simple vesicles of uncertain biological affinity from the Xiamaling assemblage. Fig 3. Various cellular aggregates from the Xiamaling assemblage. Fig 4. A broad stratigraphic range of organic-walled microfossils in the mid-Proterozoic.Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Volcanic activity drove an increase in the intensity of wildfire events, which in turn disturbed and affected terrestrial ecosystem. Volcanic activity drove an increase in the intensity of wildfire events, which in turn disturbed and affected terrestrial ecosystem. Wildfire is an important part of terrestrial ecosystem. It plays a significant role in many environmental and evolutionary innovations in geological history. The End-Permian mass extinction is the biggest extinction event in Earth's history, and the response of terrestrial vegetation systems to this event has been highly concerned in recent years. Nowadays more and more records of wildfire are reported from the Late Paleozoic, the investigations focusing on wildfire are of great significance to learn the collapse of terrestrial ecosystem and the vegetation changeover during the Permian-Triassic transition. Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Nanjing University and Yunnan University, carried out a systematic studies focused on charcoals and δ13Corg from the upper Permian of the Dalongkou section in Xinjiang Uygur Autonomous Region and of the Lengqinggou section in Guizhou, Southwest China. The results were published on Earth-Science Reviews and Frontiers in Earth Science. In Dalongkou section, charcoals from several stratigraphic horizons in the lower-middle Guodikeng Formation evidenced the frequency of palaeo-wildfires during the late Permian. The reflectance values of the charcoals indicate that surface fires were dominant throughout the sequence, with fire regime changing in the upper of the Guodikeng Formation from higher reflectance to extremely low reflectance. It probably hints at a vegetational impoverishment and the lack of fuel during that time. The distribution of all categories of the charcoals, the difference of cuticles and the evidence of spore-pollen also support the deforestation stage. In addition, the coupling of the Hg/TOC peaks and the organic carbon isotope (δ13Corg) values and the abundance of the charcoals in the sequence indicates that volcanic activities could be the deep-seated drivers for wildfires and the δ13Corg change. The work of Lengqinggou section shows that charcoals from the Xuanwei Formation occurred more frequently, with higher reflectance and diversity, while that from the Kayitou Formation exhibit low reflectance and diversity. This phenomenon supports the point that the vegetation had changeover from rainforest to herb land between the two formations. Meanwhile, the fire regime also changed from high temperature crown fire to the ground fire with lower temperature. Furthermore, an ash bed in the uppermost coal in the Xuanwei Formation was concerned. Detailed sampling shows that an abrupt excursion of δ13Corg and reduction of charcoal abundance occurred immediately above the volcanic ash. It suggests that the intensive wildfire associated with volcanism culminated at that time, leading to the eventual vegetation changeover of the terrestrial ecosystems in Southwest China during the Permian-Triassic transition. The works were supported by the Strategic Priority Research Programs (B) of the Chinese Academy of Sciences and the National Natural Science Foundation of China and CAS. Related Article: Cai, Y.F., Zhang, H. *, Cao C.Q., Zheng, Q.F., Jin, C.F., Shen, S.Z., 2021. Wildfires and deforestation during the Permian–Triassic transition in the southern Junggar Basin, Northwest China. Earth-Science Reviews 218 (7): 103670. DOI: 10.1016/j.earscirev.2021.103670 Cai, Y.F., Zhang, H. *, Feng, Z., Shen, S.Z., 2021. Intensive wildfire associated with volcanism promoted the vegetation changeover in Southwest China during the Permian-Triassic transition. Frontiers in Earth Science. 9:615841. https://doi.org/10.3389/feart.2021.615841 SEM images of charcoal from the Dalongkou section in Xinjiang Uygur Autonomous Region, Northwest China Co-variation diagrams for the δ13Corg values, Hg/TOC values, charcoal abundance, reflectance and types of fossil charcoal in the Dalongkou section SEM images of charcoal from the Lengqinggou section in Guizhou Province, Southwest China Stratigraphic column and δ13Corg, charcoal abundance and types of fossil charcoals in the Lengqinggou section, Guizhou Province, Southwest China Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
