The study reveals, although these taxa have been noted by striking similarities in reticulate venation patterns, their disparate positions on the major seed-plant phylogenies indicates, in most cases, structural similarities of meshed venation in many plant groups are likely to be superficially convergent traits adopted for similar functional benefits. A great number of fossil plant taxa are characterized by similar-shaped leaves, leaflets and anastomosing venation that have commonly been assigned to the wrong taxon where only fragmentary or ill-preserved material is available. Venation architectures and cuticular micromorphology of leaf fossils play pivotal roles in higher-level taxonomic segregation, therefore, the standardized descriptions of vein cross-connection types and stomatal features between analogical taxa are indispensable for their morphological comparisons and phylogenetic analysis. Recently, on leaf vein structure and epidermal characteristics of three morphologically similar fossil plant taxa commonly found in the Paleozoic and Mesozoic eras, which provided new insights into the systematic classification and evolutionary history of these taxa. The study provides new insights into the systematic classification and evolutionary history of these taxa. Recently, XU Yuanyuan, a PhD student at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the joint guidance of Research Professor WANG Yongdong, and Prof. Stephen McLoughlin, Swedish Museum of Natural History, carried out in-depth comparative studieds on the investigations of standardized comparisons between three morphologically similar genera, i.e., Glossopteris, Sagenopteris and Anthrophyopsis, which provided more comprehensive and new perspectives to assess whether venational pattern or stomatal characters can indicate close affinities of fossil plant taxa. This study was published in the journal of Review of Palaeobotany and Palynology. Reticulate venations occur in a broad range of plant groups dating back at least to the Pennsylvanian (Fig. 1). In many cases, anastomosing venation styles are markedly similar, and unclear whether these similarities are superficial and convergent or are genuinely homologous. Detailed observations and standardized descriptions of vein cross-connection types of Glossopteirs, Sagenopteris and Anthrophyopsis led to the functional analyses of their reticulate vein systems (Fig. 2). “Our study reveals, although these taxa have been noted by striking similarities in reticulate venation patterns, their disparate positions on the major seed-plant phylogenies indicates, in most cases, structural similarities of meshed venation in many plant groups are likely to be superficially convergent traits adopted for similar functional benefits.”, XU says. Cuticular characters, especially the stomatal complexes are arguable among the most consistent micromorphological features in fossil plants. Several traditional comparative studies and phylogenetic analysis incorporating fossil seed plants have generally proposed Glossopterids (Glossopteris), Caytoniales (Sagenopteris) and Bennettitales (Anthrophyopsis) to be close relatives of angiosperms. However, Glossopteris has perigenous and monocyclic—normally stephanocytic to actinocytic—stomata commonly protected in pits or by overarching papillae; Sagenopteris has surficial anomocytic or stephanocytic stomata with weakly modified subsidiary cells; and Anthrophyopsis has distinctive paracytic stomata consistent with those of Bennettitales (Fig. 2). This study opens up new avenues for evaluating our understanding of ancient plant taxonomy and provides a foundation for future investigations in this field. In general, the findings in this study challenge some previous notion of putatively close relationship of glossopterids (Glossopteris), Caytoniales (Sagenopteris) and Bennettitales (Anthrophyopsis), and emphasize the importance of considering ecological convergence in the interpretation of ancient plant characteristics. XU says, “While leaf characteristics have historically been used for classification, the study underscores the need for greater emphasis on the examination of reproductive organs to provide a more accurate understanding of the diversity and evolutionary history of these ancient plants.” This study was co-sponsored by the National Natural Science Foundation of China, Strategic Priority Research Program (B) of the Chinese Academy of Sciences, State Key Laboratory of Palaeobiology and Stratigraphy, Swedish Research Council and CSC. Reference: Yuanyuan Xu, Yongdong Wang*, Stephen McLoughlin*, 2023. How similar are the venation and cuticular characters of Glossopteris, Sagenopteris and Anthrophyopsis. Review of Palaeobotany and Palynology, 316, 104934. https://doi.org/10.1016/j.revpalbo.2023.104934. Fig. 1. Geological range of some representative reticulate plant fossil taxa. Fig. 2. Representative leaf fragments of Glossopteris (A–D), Sagenopteris (E–G) and Anthrophyopsis (H–J), showing leaf forms and venation styles. Scale bars for A, C, E, G, H–J = 10 mm, for B, D, F = 5mm. Fig. 3. Micromorphological features of Glossopteris (A–G), Sagenopteris (H–J) and Anthrophyopsis (K–P). Scale bars for A–D, N = 100 μm, for E–G = 10 μm, for H = 100 μm, for I = 300 μm, for J, K–L = 50 μm, for J, M, O = 30 μm, P = 20 μm.
Contact: LIU Yun, Propagandist Email:yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Associate Research ProfessorLI Qijian Li and Research ProfessorLI Yue from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and their collaborators, have reported Late Ordovician sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. Ordovician strata record a unique transition from microbial-dominated towards metazoan-dominated reefs. With their first radiation of sphinctozoan sponges during the Ordovician, they occur in thrombolites in South China, representing the initial expansion of sphinctozoan-grade sponges from level bottom to reef settings. Most previous studies mainly focused on the substantial ecological changes in the reef ecosystem. However, little is known about how abiotic carbonate precipitates link to the transition in biotic composition during the Great Ordovician Biodiversification Event. Recently, Associate Research ProfessorLI Qijian Li and Research ProfessorLI Yue from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and their collaborators, have reported Late Ordovician sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. The study entitled “Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum” has been published in Palaeogeography，Palaeoclimatology，Palaeoecology. The reefs show a three dimensional skeletal framework that is mainly constructed by Corymbospongia and Amsassia. Microbes and subsequent cementation cover the primary skeletons, enhancing the stability of the framework (Fig.1). Isopachous crystalline crusts are distinct in the boundstone of the reefs (Fig.2). Submarine synsedimentary cementation is critical to stabilization of reef frameworks and to limit mechanical erosion. Large amounts of marine cements are widely developed in modern tropical reefs, while early marine cementation has been rarely reported as an important process to promote carbonate accumulation in the early Palaeozoic reefs. The skeletal-microbial-cement reefs of the Sanqushan Formation share many similarities with reefs reported from contemporaneous strata in North China and Central Nepal. The substantial synsedimentary cementation on the seafloor found in this study provide key evidence to understand the complex feedback relationships between eco-evolutionary dynamics and early diagenesis in Late Ordovician reefs during the icehouse conditions (Fig.3). Reference: Li, Q.J.*, Na, L., Yu, S.Y., Mao, Y.Y., Kershaw, S., Yue, L., 2023. Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum. Palaeogeography, Palaeoclimatology, Palaeoecology. 624(15): 111642. https://doi.org/10.1016/j.palaeo.2023.111642. Thin section photomicrographs of the Corymbospongia-Amsassia framestone. A) Overview of the framestone, showing the scaffold structure of crowded Corymbospongia (Co) and Amsassia (Am); B) Detail of the framework constructed by the intertwined Corymbospongia (Co) and Amsassia (Am), showing exaulos tubes (red arrows) of sphinctozoans and a few small cavities (yellow triangles); C) Close-ups of the framestone showing the details of sphinctozoan chambers (yellow triangles) and exaulos tubes (Ex). Note that red triangles indicate isopachous cements in the chambers, while red triangles indicate a small cavity; D) Allonema (Al) encrusts skeletons of Corymbospongia (Co). Yellow triangles indicate the wall of a chamber. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Details of abiotic cements, taken under (A & C) stereomicroscope and (B & D) cathodoluminescence microscope. 1: isopachous cement, 2: the second generation of cement, 3: the third generation of cement, Mi: microbial fabrics. Yellow triangles show matched points between stereomicroscope and cathodoluminescence photos. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) The principal types of reefs in Ordovician (A-C). Category C possesses a macroskeletal framework. In category B, the skeletal forms are locally juxtaposed. Category A is the microbial reefs; D-E) Microscopic textures of the reefs, showing the changes in early diagenesis from Early Ordovician to Mid-Late Ordovician reefs.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Associate Research Professor ZHENG Quanfeng and Research Professor CAO Changqun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), made high-resolution sedimentological and ichnological studies on the upper member of the Talung Formation at Shangsi, Guangyuan City, Sichuan Province, to reveal the dynamic process of turbidity current-induced benthic-marine oxygenation evidenced by sequential ichnocoenoses. Trace fossils are fossilized structures produced on or within a substrate by the life processes of ancient organisms, including tracks, trails, burrows, borings, and other structures (eg, root molds, egg fossils, coprolites, etc). Ichnocoenosis is a suite of trace fossils representing the work of a particular benthic community. An ichnocoenosis is a powerful tool for reconstructing sedimentary settings and retrieving palaeoenvironmental factors (eg, relative oxygen content, water depth, salinity, etc). However, it is a challenge to recognize and apply ichnocoenoses in the geological record for the sake of time-averaging by non-deposition or slow depositional rates and the destruction and elimination by deeper-tiered traces. Additionally, turbidity currents have proven to be an important mixing way for stratified waterbodies in modern oxygen-deficient basins. These density flows transport sediments and oxygen-rich waters from shallow-water environments to deep basins, which can considerably change the chemistry and oxygen content of the deep-basin waters. However, turbidity current-induced oxygenation events in oxygen-deficient basins have rarely been directly demonstrated in the geological record. As a common mechanism for the oxygenation of water bodies in oxygen-deficient basins, turbidity current has not received the necessary attention. Recently, Associate Research Professor ZHENG Quanfeng and Research Professor CAO Changqun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), made high-resolution sedimentological and ichnological studies on the upper member of the Talung Formation at Shangsi, Guangyuan City, Sichuan Province, to reveal the dynamic process of turbidity current-induced benthic-marine oxygenation evidenced by sequential ichnocoenoses. This study was published on Geological Journal on July 11. The research team found that the studied interval consists mainly of background sedimentation of black shale and rapid event sedimentation of fine-grained calciturbidite. The black shale contains fine laminations and weak bioturbation and lacks primary burrows (burrows produced during the deposition of the black shale), indicating anoxic benthic marine conditions. The calciturbidite was intensely bioturbated, and contain abundant primary burrows. Based on cross-cutting relationships and burrow-fill features, three successive ichnocoenoses can be recognized in the typical calciturbidites: (1) the early-phase Thalassinoides/?Scolicia ichnocoenosis, including Thalassinoides/?Scolicia, Zoophycos, and Planolites, which has the largest maximum burrow diameter (MBD) and maximum penetration depth (MPD) and represents the highest oxygen level among the three ichnocoenoses; (2) the later-phase Planolites-Zoophycos ichnocoenosis, including Zoophycos, Planolites, large Chondrites, and small Chondrites, which has the moderate MBD and MPD and represents the moderate oxygen level; (3) the latest-phase Zoophycos ichnocoenosis, composed of monospecific Zoophycos burrows, which has the smallest MBD and MPD and represents the lowest oxygen level. The Thalassinoides/?Scolica ichnocoenosis was produced at the very end and immediately after the emplacement of the turbidites, representing the climax of the turbidity-induced oxygenation. The Planolites-Zoophycos ichnocoenosis was produced during a later stage after the emplacement of the turbidites, indicating a relatively more reducing bottom-water condition. The Zoophycos ichnocoenosis was produced during a further later but relatively long stage after the emplacement of the turbidites, indicating a much more reducing bottom-water condition. “This study demonstrated that turbidity current is an effective way to locally oxygenate bottom waters in oxygen-deficient basins which has significant impacts on benthic communities”, says ZHENG. This research was supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences. Reference: Zheng, Q.F.*, Cao, C.Q., 2023. Dynamic process of turbidity current-induced benthic-marine oxygenation evidenced by sequential ichnocoenoses: An example from a Late Permian oxygen-deficient basin. Geological Journal, https://doi.org/10.1002/gj.4837. Fig. 1. Lithofacies (a), microfacies (b ~ f), and sedimentological logs (g) of the study interval. (Image by NIGPAS) Fig. 2. Vertically polished slab (a) and line drawing (b) of the studied interval. (Image by NIGPAS) Fig. 3. Schematic drawings showing the ichnocoenosis succession and the dynamic process of turbidity current-induced benthic-marine oxygenations during the deposition of the studied interval. (Image by NIGPAS)
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), collaborated with other scientists from USA and UK, discovered 16 new mermithids associated with their insect hosts from mid-Cretaceous Kachin amber (about 100 million years ago). This study reveals what appears to be a vanished history of nematodes that parasitized Cretaceous insects, and has been published on eLife on July 14, 2023. Nematodes (roundworms) are distributed worldwide in almost all habitats, however, nematodes are exceedingly rare in the fossil record, since most of them are small, with soft bodies and concealed habits. The Mermithidae represent a family of nematodes that are large compared with other nematodes, and they tend to exit their hosts even before maturation if their hosts are stressed. Thus, mermithid nematodes are most likely of all nematodes to occur as recognizable fossils. Recently, the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), collaborated with other scientists from USA and UK, discovered 16 new mermithids associated with their insect hosts from mid-Cretaceous Kachin amber (about 100 million years ago). This study reveals what appears to be a vanished history of nematodes that parasitized Cretaceous insects, and has been published on eLife on July 14, 2023. Nematodes play key roles in ecosystems by linking soil food webs and facilitating nutrient element cycling. Mermithid nematodes are obligate invertebrate parasites which occur in insects, millipedes, crustaceans, spiders, molluscs and earthworms. They can affect the morphology, physiology, and even the behaviour of their hosts. Hosts usually die when the mermithids exit, which is why mermithids have been considered as biological control agents, especially against mosquito larvae that transmit malaria. Mermithid nematodes, these fossils mainly discovered from Eocene Baltic amber (11 species) and Miocene Dominican amber (9 species), but only four pre-Cenozoic species have previously been recorded. Therefore, little is known about their early evolution of parasitism. LUO Cihang, a PhD canditate student, supervised by Prof. WANG Bo from NIGPAS, carried out a systematic study on the 16 new mermithids of the Kachin amber. In this study, sixteen new mermithids associated with their insect hosts were described, including 9 new species, which triples the diversity of Cretaceous Mermithidae (from 4 to 13 species). Meanwhile, according to new records of this study, nine insect orders are now known to have been infested by mermithid nematodes in Kachin amber and this number is even higher than that of Baltic amber and Dominican amber (six and three insect orders, respectively). This result suggests that mermithid parasitism of insects was actually widespread during the mid-Cretaceous, and probably already played an important role in regulating the population of insects in Cretaceous terrestrial ecosystems. At the same time, it was found that 12 of these 16 mermithids of the Kachin amber include previously unknown hosts. There are no previous extant or extinct records of nematodes attacking bristletails (Archaeognatha), but one is now discovered in this study. No barklice (Psocodea) are parasitized by mermithids today, but three different barklouse were found parasitizing by mermithids. Two members of the extinct planthopper family Perforissidae were also parasitized by mermithids, thus providing the oldest record of mermithid parasitism of planthoppers. Furthermore, this study provides the first fossil records of mermithids parasitizing dragonflies (Odonata), earwigs (Dermaptera), crickets (Orthoptera) and cockroaches (Blattodea), four host associations predicted from extant records but without fossil evidences. These fossils indicate that mermithid parasitism of invertebrates was already widespread and played an important role in the mid-Cretaceous terrestrial ecosystem. In addition, among the insect hosts of mermithids preserved in Kachin amber, only one of the nine orders (Diptera) is holometabolous (i.e., insects with “complete” metamorphosis), whilst it is four out of six (Hymenoptera, Trichoptera, Lepidoptera and Diptera) in Baltic amber and all three insect host orders (Hymenoptera, Coleoptera and Diptera) are holometabolous in Dominican amber. The situation is similar when referring to the amount of nematode parasitism after compiling nematode–host records in these three best-studied amber biotas. In Kachin amber, only about 40% of the hosts are holometabolous, while this percentage increases to 80% in Baltic and Dominican amber. Holometabola are the most important hosts of extant mermithids as well as all invertebrate-parasitizing nematodes and this hexapod subgroup dominated the insect fauna during the Cretaceous. This study indicates that nematodes had not completely exploited Holometabola as hosts in the mid-Cretaceous, and non-holometabolous insects (i.e., insects without “complete” metamorphosis) were more available as hosts in the mid-Cretaceous. The widespread association between nematodes and Holometabola might have formed later. Furthermore, our study shows that in contrast to their Cenozoic counterparts, Cretaceous nematodes including mermithids are more abundant in non-holometabolous insects. This result suggests that nematodes had not completely exploited the dominant Holometabola as their hosts until the Cenozoic. The high diversity of mermithid nematodes during the mid-Cretaceous as shown in this study provides a glimpse into the structure of ancient parasitic nematode–host associations and their evolution over the past 100 million years,” says LUO, “these discoveries bring new opportunities to study the evolution of parasitism through the medium of amber and provide the direct evidence to reconstruct Cretaceous terrestrial ecosystem.” A related Insight article written by Kenneth De Baets et al. has also been published, and they commented that this paper provided a good example to study the coevolution of nematodes and their invertebrate and helped scientists to better estimate the extinction risk of modern species. This research was supported by the National Natural Science Foundation of China, Chinese Academy of Sciences, and Ministry of Science and Technology of China. Reference: Luo Cihang, Poinar G.O., Xu Chunpeng, Zhuo De, Jarzembowski E.A., Wang Bo, 2023. Widespread mermithid nematode parasitism of Cretaceous insects. eLife 12, e86283. https://doi.org/10.7554/eLife.86283. The information of related Insight article: De Baets K., Vanadzina K., Schiffbauer J., 2023. Trapped in time. eLife 12, e90008. https://doi.org/10.7554/eLife.90008. Fig.1 Mermithids and their insect hosts from mid-Cretaceous Kachin amber (~99 Ma; million years ago) (Part I). Fig.2 Mermithids and their insect hosts from mid-Cretaceous Kachin amber (~99 Ma; million years ago) (Part II). Fig.3 The fossil record of Mermithidae plotted on the phylogenetic tree of insects. Fig.4 The occurrence frequency of invertebrate–nematode associations from mid-Cretaceous Kachin amber, Eocene Baltic amber and Miocene Dominican amber.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Early Land Plants working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Research Professor XU Honghe, conducted a synthetic study on palynological flora from the Llandoverian Kalpintag Formation of the Tarim Basin, southern Xinjiang. The related research results were published online on the international interdisciplinary journal, Journal of Asian Earth Sciences. The Middle Ordovician-early Silurian is the key period for the origin and early evolution of morphological innovations of land plants. It is widely accepted that the earliest unambiguous fossil evidence of land plants can be traced to the Middle Ordovician Dapingian-Darriwilian stages (ca.468-463Ma), which is represented by dyads and tetrahedral tetrads from the Gondwana continent. In the Sheinwoodian (Wenlock, Silurian) rocks (ca.432Ma), the earliest sporophytes of land plants, e.g., Cooksonia barrandei typically seen in textbook, were found. Strata of the Middle Ordovician-early Silurian interval are target horizon for study on the origin of early land plants. However, the progress of related research is signally delayed for the lacking of terrestrial remains from the lower Paleozoic. Recently, Early Land Plants working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Research Professor XU Honghe, conducted a synthetic study on palynological flora from the Llandoverian Kalpintag Formation of the Tarim Basin, southern Xinjiang. The related research results were published online on the international interdisciplinary journal, Journal of Asian Earth Sciences. In this study, the land plant microfossils revealed from the Kalpintag Formation mainly consist of cryptospores, with only a few tubes and cuticle-like sheets, but no trilete spores have been observed. The Kalpintag cryptospore-producing plants largely inherited, with slight variation, from their predecessors of a Late Ordovician age. Different from the typical MCA assemblage of early Silurian sporomorphs in China, the Kalpintag cryptospores do not lack dyads, and instead they are dominated by Dyadospora and Pseudodyadospora. Thus, it can be considered that the dyad-producing plants were once the dominant among early non-vascular land plants in the Tarim paleoterrain. By taxonomic comparisons of global coeval sporomorph records, combined with quantitative analyses (Cluster Analysis and Nonmetric Multidimensional Scaling Analysis), the Kalpintag cryptospores show more closely related to those in northern Chad, northeastern Libya and central Saudi Arabia. XU says, “the geographical zonation of sporomorph might emerge in the Llandovery, during which the geographical proximity of the Tarim Plate to western Gondwana is suggested”. This study was supported by the National Key R&D Program of China; and Chinese Academy of Sciences. This work is a contribution to the Deep-time Digital Earth (DDE) Big Science Program. Reference: Wang K, Liu B-C, Wang Y, Xu H-H*. A palynoflora of southern Xinjiang, China, and the proximity of the Tarim Plate to western Gondwana during the Llandovery (Silurian). Journal of Asian Earth Sciences. 2023, 105769. https://doi.org/10.1016/j.jseaes.2023.105769. Fig.1. Cryptospores from the Llandoverian (early Silurian) Kalpintag Formation, southern Xinjiang (Scale bar is 10μm for all images) Fig.2. (1) The paleogeographical distribution of sporomorphs (cryptospores and trilete spores) during the early Silurian (Llandovery, ca 440 Ma). The paleogeographical reconstruction is modified from Torsvik (2019). (2) Cluster analysis at the genus level for the Llandovery sporomorphs. (3) Nonmetric multidimensional scaling analysis at the genus level for the Llandovery sporomorphs. (4) Cluster analysis at the species level for the Llandovery sporomorphs. (5) Nonmetric multidimensional scaling analysis at the species level for the Llandovery sporomorphs.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, leading by Research Prof. ZHAO Fangchen and PhD student SUN Zhixin from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Prof. YANG Aihua from Nanjing University and other colleagues, discovered a new lower Cambrian trilobite assemblage from the Lake Zone. This diverse trilobite assemblage provides new insights into trilobite evolution and early Cambrian biogeographic affinity of the Lake Zone. The study was published in Journal of Paleontology. As an important part of the Central Asian Orogenic Belt, Mongolia has a complex geotectonic history. Unlike several cratonal block in central Mongolia, the Lake Zone in western Mongolia formed part of the magmatic-arc systems in the Cambrian period, characterized by the extensive distribution of subduction complexes and magmatic rock. This makes the biological features of the Lake Zone very important for understanding the evolution and paleogeography of the Palaeo-Asian Ocean in the Cambrian. However, no detailed study has been done in this remote area except a small amount of preliminary investigation of Cambrian fossils in the last century. Recently, leading by Research Prof. ZHAO Fangchen and PhD student SUN Zhixin from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Prof. YANG Aihua from Nanjing University and other colleagues, discovered a new lower Cambrian trilobite assemblage from the Lake Zone. This diverse trilobite assemblage provides new insights into trilobite evolution and early Cambrian biogeographic affinity of the Lake Zone. The study was published in Journal of Paleontology. The new assemblage is exposed in the Seer section, on the eastern side of Khovd, western Mongolia. Trilobite fossils were collected from uppermost Burgasutay Formation and corresponding to the earliest Cambrian Stage 4. This assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to 9 families including Catinouyia heyunensis sp. nov. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. “The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana”, says SUN. This study was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China. Reference: Sun, Z., Yang, A., Zhao, F., Zhuravlev, A., Pan, B., Hu, C., Feng, Q., Chen, X., Zhu, M. (2023). New trilobite assemblage from the lower Cambrian (upper Stage 4) of the Lake Zone, western Mongolia. Journal of Paleontology, 1-14. https://doi.org/10.1017/jpa.2023.23. Figure 1. Location and geological setting of the Seer Ridge section and correlation of lower Cambrian sections in Mongolia. Figure 2. The most abundant trilobite in Lake Zone assemblage, Kootenia spp. Figure 3. Representative genus in the Lake Zone assemblage:1-3, Pagetides; 4, Eoptychoparia; 5, Amecephalus; 6, Chondragraulos; 7, Catinouyia.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Prof. XU Honghe, Big Data Center of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led an informatic paleontological study based on fossil specimen data. The research results were published in an international, interdisciplinary, and open-accessed top journal of Earth system sciences journal, Earth System Science Data. Multi-elemental and multi-dimensional data are more and more important in the development ofdata-driven research, as is the case in modern paleontology, in which, in an examination by experts, or one day artificial intelligence. Construction of integrated dataset of fossil specimens is essential to basic study of paleontology and stratigraphy, helps to shale gas exploration, and furthermore promotes the artificial intelligence applying in paleontology and stratigraphy. Recently, Prof. XU Honghe, Big Data Center of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led an informatic paleontological study based on fossil specimen data. The research results were published in an international, interdisciplinary, and open-accessed top journal of Earth system sciences journal, Earth System Science Data. “It took us over two years to finish the construction of this multi-dimensional dataset of graptolite specimens,” says XU, “our process includes specimen selection, curation and revision, scientific information summarizing, photography, data cleaning, and cloud storage and backup.” This dataset includes 1550 graptolitespecimensthe Ordovician-Silurian strata of South China, which are significant in global stratigraphic correlation and shale gas exploration,and it covers 113 graptolite species or subspeciesin systematic classification. The dataset contains 2951 high-resolution images and a datatable of each specimen’s scientific information, including the taxonomic, geologic, and geographic information,comments, and references. “Our dataset provides images for specialists or general users worldwide, is supported bythe tool FSIDvis (Fossil Specimen Image Dataset Visualizer), which we developed to facilitate the interactiveexploration of the rich-attribution image dataset, and includes a nonlinear-dimension reduction technique, t-SNE(t-distributed stochastic neighbor embedding), to project image data into a two-dimensional space to visualizeand explore the similarities.” XU says.Individual specimens are denoted by different colors and grouped in the visualization. These groups also taxonomically match different graptolite families. The dataset potentially contributes to virtual examinations of specimens, globalbio-stratigraphic correlation, and improvement of the shale gas exploration efficiency. This work is a contribution to the Deep-time Digital Earth (DDE) Big Science Program. Reference: Xu, H.-H., Niu, Z.-B., Chen, Y.-S., Ma, X., Tong, X.-J., Sun, Y.-T., Dong, X.-Y., Fan, D.-N., Song, S.-S., Zhu, Y.-Y., Yang, N., and Xia, Q. 2023. A multi-dimensional dataset of Ordovician to Silurian graptolite specimens for virtual examination, global correlation, and shale gas exploration. Earth Syst. Sci. Data. 15, 2213–2221, https://doi.org/10.5194/essd-15-2213-2023. Fig 1. The process of creating the graptolite specimen image dataset. Fig 2. Geographic distribution (a) and geologic range (b) of graptolite species of our dataset. Fig 3. t-SNE visualization of our graptolite specimen images.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Enhanced terrestrial input brings severe influence on modern coral reefs, accompanied with coral death and morphologic variation. Similar scenarios could be suspected for geological times, but reef coral resilience is still an enigma. Recently, researchers systematically documented the morphologic variation of reef corals and terrestrial sediment input during the Middle-Late Mississippian, and uncovered the relationship between size changes in reef corals and terrestrial input during the onset of the late Palaeozoic Ice Age (LPIA). Enhanced terrestrial input brings severe influence on modern coral reefs, accompanied with coral death and morphologic variation. Similar scenarios could be suspected for geological times, but reef coral resilience is still an enigma. Recently, researchers systematically documented the morphologic variation of reef corals and terrestrial sediment input during the Middle-Late Mississippian, and uncovered the relationship between size changes in reef corals and terrestrial input during the onset of the late Palaeozoic Ice Age (LPIA). The research was conducted by Associate Professor YAO Le and Assistant Professor LIN Wei from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), collaborated with Professor Markus Aretz from the University of Toulouse III, Professor David J. Bottjer from the University of Southern California, and Professor WANG Xiangdong from the Nanjing University, and the results were published online on 24th May, 2023 in Proceedings of the Royal Society B. LPIA is the only period containing similar atmospheric CO2 concentration to modern times, since the evolution and proliferation of animals and plants. Studies on the marine biota-environment coevolution during the LPIA could provide insights into the evolution of modern marine ecosystems. During the Middle-Late Mississippian (late Visean to Serpukhovian stages), prominent Hercynian orogeny and terrestrial plant proliferation led to enhanced terrestrial silicate weathering, sediment and nutrient input, which resulted in a dramatic climate cooling and sea-level fall. Recent studies uncovered that an obvious positive shift in brachiopod oxygen isotope occurred across the Asbian-Brigantian boundary (late Visean), indicating the drop in sea-surface temperature and the onset of the major phase of the LPIA. During this time, the marine coral reef ecosystems collapsed associated with distinct decline in benthic fauna diversity. Hence, studies on the size variation in the Middle-Late Mississippian reef corals could provide the evolutionary trend of modern marine reef corals under increasing influence from terrestrial sediment influx. In this study, the impact of enhanced terrestrial runoff is tested on size (corallite/tabularium diameter and septal number) variations of the Serpukhovian colonial corals Aulina rotiformis and Lithostrotion decipiens from the Yashui, Malanbian, Wangjiawan and Jianshanzi sections, which develop along a gradient of open marine carbonate to near-shore siliciclastic facies in South China. Elemental mapping was also conducted for reef corals and their surrounding rocks. “Along this gradient, their sizes decrease from carbonate, through intermediate carbonate-siliciclastic, to siliciclastic facies”, YAO says, “while this is consistent with increasing abundance of terrestrial materials of high silicon, aluminium and phosphorus values.” On a larger million-year-long interval and for several palaeocontinents, size data of Lithostrotion decipiens and Siphonodendron pauciradiale show a distinct decline across the Asbian-Brigantian boundary in the late Visean, when enhanced terrestrial weathering and sediment input occurred during the LPIA onset. This study reveals the spatial-temporal evolutionary trend of reef coral size and terrestrial sediment input. It suggests that terrestrial sediment and nutrient input may have mainly controlled phenotypic plasticity in Mississippian reef corals, with a decrease in size as a component of resilience across the LPIA onset. In addition, these findings can provide insights into the long-term evolution and regulation of modern marine coral reefs as corals containing the ability to decrease in size are more resilient under high sedimentation from terrestrial runoff. This research was supported by the National Natural Science Foundation of China, the Youth Innovation Promotion Association of the CAS, and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences. Reference：Yao, L*., Lin, W., Aretz, M., Bottjer, D.J., Wang, X.D., 2023. Colonial coral resilience by decreasing size: reaction to increased detrital influx during onset of the late Palaeozoic Ice Age. Proc. R. Soc. B, 290, 20230220. https://doi.org/10.1098/rspb.2023.0220.
Figure 1. Evolutionary pattern of Mississippian reef coral diversity and total marine biodiversity, including recovery phase, proliferation phase and extinction phase of reef corals during early to late Visean, middle part of late Visean, latest Visean to Serpukhovian, respectively. Figure 2. Variation in the septal number of the colonial coral species Lithostrotion decipiens and Aulina rotiformis, and correlation diagrams of tabularium diameter and septal number of L. decipiens and A. rotiformis in the Yashui, Malanbian, Wangjiacun and Jianshanzi sections. Figure 3. Thin-section photographs (a–c) and their corresponding elemental–mapping photographs (d–o) of the colonial coral species Lithostrotion decipiens in the Yashui, Malanbian and Wangjiacun sections from left to right sequentially. Figure 4. Size evolutionary pattern of the colonial coral species Siphonodendron pauciradiale and Lithostrotion decipiens, and their relations to the changes in terrestrial weathering (87Sr/86Sr), sea surface temperature, low-latitude sea-level and high-latitude glacial deposits from the late Visean to Serpukhovian stages.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, the Early Land Plant working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe, conducted a systematic paleoecological study based on plant fossils from the Lower Devonian of Guangxi. The related research results were published in an open-accessed journal of iScience. The study of paleoecology involves the fossil record and paleoenvironmental information of many kinds of organisms. Fossils preserved in strata usually have a certain relation with each other. It is an important means to understand the biological evolution and its environmental background to carry out multi-scaled comprehensive analysis and study on a variety of fossils preserved together. Recently, the Early Land Plant working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe, conducted a systematic paleoecological study based on plant fossils from the Lower Devonian of Guangxi. The related research results were published in an open-accessed journal of iScience. Testate amoebae are a group of widespread microcosmic protists and play a crucial part in Earth’s biosphere. Testate amoebae stand out with their unique test (shell), usually 20–150 μm in size, and in the tree of eukaryotic life, are known as a polyphyletic group that consists of three unrelated taxonomic lineages. As free-living protists, extant testate amoebae are distributed in most kinds of freshwater or terrestrial habitats, e.g., river, pond, peat land and soil, but as well as in brackish and marine waters, and are of great significance to the flow of matter and energy in ecosystems. It has been generally considered that the evolutionary history of testate amoebae could be traced back to the late Tonian (early Neoproterozoic, ca. 800–720 Ma), as evidenced by the extensive records of marine vase-shaped microfossils in this period. However, not much is known about the Paleozoic testate amoeba fossils, as of now. The oldest unambiguous occurrence of Paleozoic testate amoebae is a freshwater arcellinid species from the Lower Devonian Rhynie chert followed by scattered reports from the upper Carboniferous and Permian. There is also rare knowledge about the internal structures of fossil testate amoebae. Except few possible reproductive cells or resting cysts in phosphatized or amber-preserved specimens. There were no any other bio-related structures inside the shells of fossil testate amoebae have been observed. In this study, a shallow-marine testate amoebae is firstly discovered as exquisitely preserved vase-shaped microfossils from the Lower Devonian Cangwu Formation in Guangxi, southwestern China, and based on morphological characters, interpret them as a new fossil species of arcellinid testate amoebae. Additionally, it is shown that distinct acetabuliform structures are preserved in the shell of these testate amoeba, and infers possible sources of these internal structures. “Our testate amoeba co-occurs with several types of plant remains, e.g. Zosterophyllum sinense and some rhyniophytoids, and more recently reported Houia (Euchelicerata)”,XU says, “it can be suggested that the fossil-bearing horizon represents a shallow-water marine environment.” These fossils extend the record of marine vase- shaped microfossils into the Early Devonian, during which the earliest freshwater testate amoebae occurred. Recent advances in molecular phylogeny and microbial paleobiology of testate amoebae raise a scenario that, within Arcellinida lineages, the marine-freshwater transition probably occurred multiple times and only during the Phanerozoic. That arcellinids occurred in both the freshwater and shallow-marine environments in the Early Devonian concurs with the very possibility. This work is a contribution to the Deep-time Digital Earth (DDE) Big Science Program. Reference: Wang K, Xu H-H*, Liu B-C, Bai J, Wang Y, Tang P, Lu J-F, Wang Y. 2023. Shallow-marine testate amoebae with internal structures from the Lower Devonian of China. iScience. 26(5), 106678. https://doi.org/10.1016/j.isci.2023.106678. Fig 1 Palaeoecosystem reconstruction of the Lower Devonian Cangwu Formation in southwestern China. Fig 2 Three-dimensional reconstruction of Cangwuella ampulliformis from the Lower Devonian Cangwu Formation, based on synchrotron radiation X-ray tomography.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGAPS), Nanjing University and Yunnan University, have confirmed there were large-scale high-temperature wildfire combustion events through high-precision organic geochemical analysis of biomarker compounds polycyclic aromatic hydrocarbons, providing important insights into the collapse of terrestrial ecosystems and the changeover of vegetation during the Permian-Triassic (P-T) transition period. The end-Permian mass extinction (EPME) occurred ～251.94 million years ago, was the most severe extinction event of the Phanerozoic, devastating both marine and terrestrial ecosystems, with the loss of ～81% and ～89% marine and terrestrial species, respectively. Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGAPS), Nanjing University and Yunnan University, have confirmed there were large-scale high-temperature wildfire combustion events through high-precision organic geochemical analysis of biomarker compounds polycyclic aromatic hydrocarbons, providing important insights into the collapse of terrestrial ecosystems and the changeover of vegetation during the Permian-Triassic (P-T) transition period. The results were published on Earth and Planetary Science Letters. Intensive volcanic activities around the Siberian Traps large igneous province and large-scale continental arc have triggered the massive release of greenhouse and poisonous gases, global warming, aridification and frequent wild？res. The abundance of PAHs, which can be important indicators for incomplete combustion of organic matter formed at higher temperatures because of wild？res, is a well-known alternative for investigating wild？re activities in geological history. Most of the previous researches on PAHs focused onthe marine records during the P-T transition period, while the researches on the terrestrial records were relatively insufficient. Therefore, the study of PAHs in non-marine strata is of great significance to understand the history of wildfires. The prehensive study on high-resolution PAHs in a non-marine P–T transitional sequence from the HK-1 drill core at the Lengqinggou section in Southwest China (Figs.1, 2). The PAHs content showed consistent significant enrichment during the P–T transitional period(Fig. 2), which was coupled with negative organic carbon isotope anomalies, revealing that there were large-scale high-temperature wildfire combustion events under the high-temperature and arid paleoclimate conditions during this period. Additionally, low-molecular-weight compounds such as Dibenzofuran (DBF) were mainly derived from the biodegradation of terrestrial plant polysaccharides and lignin. "In the HK-1 drill core, the abnormally high concentration of DBF compounds and the co-variation with the combustion-derived PAHs indicate that the PAHs were mainly derived from high-temperature wildfire combustion of terrestrial plants and the tropical rainforest vegetation systems provided sufficient fuel for large-scale wildfires during P–T transition." says ZHANG. ZHANG says, "furthermore, the low PAH contents in the Lower Triassic indicate a fuel shortage after the mass deforestation. The significantly changed PAH ratios indicated that the terrestrial ecosystem was greatly affected after the EPME." These PAH records suggested the vegetation type changed from a dense and highly diverse gigantopterid-dominated tropical rainforest ecosystem to an isoetalean-dominated herbaceous heathland-like ecosystem (Fig. 3). This work is supported by the National Natural Science Foundation of China and the Strategic Priority Research Programs of the Chinese Academy of Sciences. Reference: Jiao, S.L., Zhang, H.*, Cai, Y.F., Chen, J.B., Feng, Z., Shen, S.Z., 2023. Collapse of tropical rainforest ecosystems caused by high-temperature wildfires during the end-Permian mass extinction. Earth and Planetary Science Letters. 614, 118193. https://doi.org/10.1016/j.epsl.2023.118193. Fig.1 GC–MS total ion chromatogram of Aromatic hydrocarbon fraction of HK-1 drill core sample in Southwest China, standard compounds, and sand blank sample. Fig.2 Organic carbon isotope and selected PAH contents of HK-1 drill core in Southwest China. Fig.3 Reconstructions of the terrestrial ecosystems during the P–T transition.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
