Silurian (Telychian) conodont distribution on the Yangtze Platform of South China is quantitatively studied for the first time. Silurian (Telychian) conodont distribution on the Yangtze Platform of South China is quantitatively studied for the first time. Conodonts are of significant importance for global biostratigraphic correlation of strata containing Palaeozoic and Triassic marine faunas but this biostratigraphic utility can be complicated by their depth-controlled distribution. Temporal and spatial distribution patterns of conodonts have attracted increasing attention during the past six decades. Palaeoecological distribution of Silurian conodonts has been widely discussed, but knowledge of conodont associations in the Llandovery is uneven. Previous studies demonstrated that Telychian conodont distributions were related to the associated palaeoenvironments, therefore hindering global correlation of conodont zonations. Diverse Telychian (Llandovery Series, Silurian System) conodont faunas have been documented from the South China Palaeoplate. YAN Guanzhou, a Ph.D. candidate in the Early Paleozoic team of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the supervision of Prof. WU Rongchang, collaborated with members of the group and Dr. Ian G. Percival from Australia, based on data from six selected sections in the Yangtze Platform, the spatial distribution of the Telychian conodont associations is investigated in detail by use of multivariate statistical methods. The results of this study were recently published in the Journal of Asian Earth Sciences. On the basis of statistical analysis, two Telychian conodont biofacies can be observed in South China: the Dapsilodus-Decoriconus Biofacies which is restricted to deep-water environments, and the Apsidognathus-Galerodus Biofacies which is indicative of shallower water environments. One regression and two transgressions are deduced from relative abundance patterns of characteristic conodont taxa comprising these biofacies. Vertical changes of conodont biofacies in the Baizitian and Xuanhe sections permit the recognition of transgressive–regressive patterns which are closely similar to published sea-level curves for the Early Silurian. Pterospathodus eopennatus Therefore, it is argued that vertical variations in abundance of specific Silurian conodont taxa can be used as proxies for inferring major changes in sea-level. This research was supported by the National Natural Science Foundation of China and the Strategic Priority Research Program of the Chinese Academy of Sciences. Ian Percival publishes with permission of the Executive Director of the Geological Survey of New South Wales. Reference: Yan Guanzhou, Wu Rongchang*, Huang Bing, Percival I.G, Gong Fangyi, Wei Xin & Li Lixia. 2021. Llandovery (Silurian) conodont biofacies on the Yangtze Platform of South China and their palaeoenvironmental implications. Journal of Asian Earth Sciences, 225(2): 105044. https://doi.org/10.1016/j.jseaes.2021.105044. Scatter-plot of correspondence analysis (COA) showing the analysed Telychian (Llandovery, Silurian) sections and taxa (genera). A. Network diagram based on species-level data shows an overview of the conodont species in the Pterospathodus eopennatus Zone of the selected sections. B. Cluster analysis of the conodont species in the Pterospathodus eopennatus Zone of the selected sections.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The Lower Devonian deposits develop well and are widely distributed in the South China Plate, Its Early Devonian flora shows high endemism especially at the generic level. The Posongchong flora from the Lower Devonian of Yunnan, as a representative working area, has a total of 28 genera and 37 species of plants and over 70% genera are endemic. Several regional floras other than Yunnan have been discovered from southern China, as Pingyipu of Jiangyou, Yangling of Chongyi, and Shiqiao of Cangwu. The Lower Devonian deposits develop well and are widely distributed in the South China Plate, Its Early Devonian flora shows high endemism especially at the generic level. The Posongchong flora from the Lower Devonian of Yunnan, as a representative working area, has a total of 28 genera and 37 species of plants and over 70% genera are endemic. Several regional floras other than Yunnan have been discovered from southern China, as Pingyipu of Jiangyou, Yangling of Chongyi, and Shiqiao of Cangwu. Recently, a systematic palaeontological study based on materials from the Lower Devonian of Hezhang, Guizhou Province is conducted by the Devonian Investigation Group (DIG) of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS) , led by Prof. XU Honghe, and Dr. WANG Yao from Qufu Normal University. The related research results were published in international journals Review of Palaeobotany and Palynology and Philosophical Transactions of the Royal Society B. Abundant and diverse palynomorphs are firstly recovered from the megaplant fossil-bearing beds. The palynological assemblage is summarized as Retusotriletes triangulatus–Latosporites ovalis–Apiculiretusispora plicata (TOP) and contributes a better understanding of the Lower Devonian palynoflora of South China. Hezhang TOP palynological assemblage is dominated by trilete spores and includes 36 genera and 72 species of spores. Qualisaspora sinuata and Gneudnaspora divellomedia var. divellomedia, are for the first time discovered from the Lower Devonian of China. The TOP assemblage also dates the Danlin Formation as Pragian to early Emsian (Early Devonian) and indicates a coastal palaeoenvironment with co-occurrences of acritarch and scolecodont. The new finds of megaplant fossils from the Lower Devonian of Hezhang County, Guizhou Province, include Zosterophyllopsida Demersatheca and Euphyllophytopsida Pauthecophyton. Demersatheca contigua consists of cylindrical strobili with four longitudinal rows of sporangia decussately arranged and shows great similarities to the plant from Yunnan and Guangxi localities. Pauthecophyton hezhangensis has distinct fertile units with grouped sporangia and each unit with two or three fusiform sporangia. A new phytogeographical zone of Hezhang, Guizhou is recognized, which shows similarities with other coeval floras and contributes to a further understanding of Early Devonian flora of South China. The whole South China Plate is subdivided into four sub-regions, eastern Yunnan, Guizhou, Cathaysia, and Sichuan based on their different floral compositions. The Guizhou sub-region shares some taxa with the eastern Yunnan and Cathaysia sub-regions within South China. The common plant members of these regions are distributed around the epicontinental sea. It is suggested that the Guizhou sub-region might act as a bridge aiding plant dispersal from eastern Yunnan to Cathaysia during the Early Devonian. References: Wang Y, Bai J, Liu B-C, Wang Y, Xu H-H. 2022 New insights into the South China Lower Devonian flora based on fossils from Hezhang, Guizhou Province. Philosophical Transactions of the Royal Society B377, 20210312. https://doi.org/10.1098/rstb.2021.0312. Xu HH, Yang N, Bai J, Wang Y, Liu F, Ouyang S. 2022 Palynological assemblage of the Lower Devonian of Hezhang, Guizhou, southwestern China. Review of Palaeobotany and Palynology 297, 104561. https://doi.org/10.1016/ j.revpalbo.2021.104561. Fig1. Megaplant fossils and spores from the Lower Devonian Danlin Formation, Hezhang, Guizhou Province
Fig 2 Lower Devonian flora regions on the South China palaeogeographical map. The red dashed line with arrows and numbers indicate the probable plant dispersal routes and sequence
A new angiosperm fruit, Dilcherifructus mexicana gen. et sp. nov, from the Middle Jurassic of Mexico. This is the currently earliest record of angiosperms in the North America, and its geographical position indicates that angiosperms were already widespread in the North Hemisphere during the Jurassic. This new information prompts a rethinking on the history of angiosperms and related hypotheses. A new angiosperm fruit, Dilcherifructus mexicana gen. et sp. nov, from the Middle Jurassic of Mexico. This is the currently earliest record of angiosperms in the North America, and its geographical position indicates that angiosperms were already widespread in the North Hemisphere during the Jurassic. This new information prompts a rethinking on the history of angiosperms and related hypotheses. Recently, Prof. WANG Xin from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), published this result in the international academic journal Biosis: Biological Systems. This is also the first time that Chinese scientists have independently studied early angiosperm fruit fossils, which from North America. The fossil was collected from an outcrop of the Simon Formation near Tezoatlán, nine miles south of the city Tezoatlan, Oaxaca, Mexico. The fossils are preserved as coalified compressions embedded in yellowish siltstones (Fig. 1a). By using stereomicroscope equipped with a digital camera, the researcher observed and photographed the fruits are round-shaped, with an apical and a basal depressions, 10-13.6 mm long, 10-13 mm wide, including a seed and an enclosing pericarp (Figs. 1a-b,). The pericarp has a smooth surface, the seeds are inside the fruits, round in shape, approximately 8 mm long and 6-9 mm wide (Fig. 1a-b). A persistent style 76 μm long and 30 μm wide is in the apical depression (Fig. 1b-c). Epidermal cells of the exocarp are polygonal or rectangular in shape, 20-60 μm long, 13-38 μm wide (Figs. 2d-e). Anomocytic stoma is surrounded by approximately five epidermal cells, 36 μm long, 36 μm wide, with a slit 25 μm long, 5.4 μm wide, level with neighboring epidermal cells (Figs. 2d-e). If Dilcherifructus were taken as a seed, less hard seed content enclosed by a hard seed coat should not be visible for an observer. The situation in Dilcherifructus (Figs. 1b) is on the contrary: the inside content is obvious. This observation suggests that the internal body in Dilcherifructus is harder than the enclosing layer, a case frequently seen in angiosperm fruits: seeds inside ovary usually are harder than the enclosing fleshy ovarian wall and thus visible when squashed. The distal projection in Dilcherifructus is interpreted as a persistent style on the tip of a fruit, as frequently seen in angiosperms. Its Jurassic age suggests that origin of angiosperms is much earlier than widely accepted, while its occurrence in the North America indicates that angiosperms were already widespread in the Jurassic, although they were still far away from their ecological radiation, which started in the Early Cretaceous. This research was supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Wang Xin, The currently earliest angiosperm fruit from the Jurassic of North America, Biosys: Biological Systems, 2021, 2(4): 416-422, doi:10.37819/biosis.001.04.0160. https://eaapublishing.org/journals/index.php/biosis/article/view/160/229.
Fig. 1. General morphology of Dilcherifructus mexicana gen. et sp. nov and its details
Fig. 2. Stomata of fossil fruits under microscope
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The Cretaceous paleo-ocean has experienced multiple phases of Oceanic Anoxic Events (OAEs), which characterized by organic carbon enrichment, geochemical indicator anomalies and fossil assemblage changes. It includes three events, namely OAE 1, OAE 2 and OAE 3. The Cretaceous paleo-ocean has experienced multiple phases of Oceanic Anoxic Events (OAEs), which characterized by organic carbon enrichment, geochemical indicator anomalies and fossil assemblage changes. It includes three events, namely OAE 1, OAE 2 and OAE 3. Previous studies of OAE 1b events have been mainly based on marine sediments in western Tethys, and very little research has been conducted on Eurasia, which limits our insight into the response of terrestrial ecosystems to OAE 1b. Recently, ZHAO Xiangdong, a graduate student supervised by Prof. ZHENG Dajin and ZHANG Haichun, from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), has found the first record of OAE 1b events in the Xiagou Formation and Zhonggou Formation of the Hanxiagou Section in Jiuquan Basin, northwestern China. The results provide direct evidence to link the OAE 1b and terrestrial ecosystem in the Eurasia. The research results have been published in GSL Special Publications, an international geological journal. "In this work, we present organic carbon isotope and total organic carbon (TOC) content data analyzed from a terrestrial succession in the Xiagou and Zhonggou Formations (upper Aptian-lower Albian), in order to characterize the OAE1b in the Eurasia continental sediments," ZHAO says, "specifically, we also analyze Hg concentrations to investigate changes in the flux of volcanic materials to terrestrial environments during the OAE 1b." On the basis of zircon U-Pb age of 112.4 ± 0.3 Ma for a basalt layer from the lowermost Zhonggou Formation, the three negative δ13Corg excursions, well corresponded with the three subevents (Kilian, Paquier, and Leenhardt) of the OAE1b in the Poggio le Guaine (central Italy), Vocontian Basin (SE France) and Santa Rosa Canyon (NE Mexico) Sections, supporting the record of the terrestrial OAE 1b in the Jiuquan Basin. Five mercury enrichment intervals in Hg/TOC ratios were recognized in the Hanxiagou Section, showing a high agreement with the previous study in the Poggio le Guaine section. This consistency indicates that mercury in both sections were probably from the same source. The volcanic eruptions of the Southern Kerguelen Plateau (119.0 –109.2 Ma) provided the Hg source and probably triggered the OAE1b (~114.5–110.5 Ma). The multiple long-term spikes observed in the Hg/TOC profile could further reflect a multiple phase emplacement of the volcanism. The Hg/TOC spikes and Carbon Isotope Excursions are not strictly at the same positions in both sections, which means a potential decoupling relationship between the global shifts in δ13C and the volcanic activity (suggested by Hg/TOC). This decoupling relationship may be resulted from another unstable and unknown carbon reservoir (not directly linked to Hg emissions) activated after the volcanism. This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the Second Tibetan Plateau Scientific Expedition and Research, and the National Natural Science Foundation of China. Reference: Zhao, X.D., Zheng, D.R., Wang, H., Fang, Y.N., Xue, N.H. & Zhang, H.C. (2021). Carbon cycle perturbation and mercury anomalies in terrestrial Oceanic Anoxic Event 1b from Jiuquan Basin, NW China. GSL Special Publications. http://dx.doi.org/10.1144/SP521-2021-149. Fig. 1 Section photograph showing boundary (red line) of Xiagou and Zhonggou formations in Hanxiagou section Fig. 2. Geochemical profiles at Hanxiagou section Fig. 3. Correlation of carbon isotopic records in Hanxiagou section (Jiuquan Basin, NW China), Poggio Ie Guaine section (Umbria–Marche Basin, Italy), a composite section (Vocontian Basin, France) and the Santa Rosa Canyon section (Mexico)
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Intensive volcanism has been considered a major driver of environmental/climatic changes throughout Earth history, including global warming due to excessive volcanogenic CO2 emission, acidification, ozone depletion etc., which in turn have been perceived important killing mechanisms of mass extinctions. However, direct evidences of the linkage between volcanism and paleoenvironmental /paleoclimatic perturbations are still lacking. Intensive volcanism has been considered a major driver of environmental/climatic changes throughout Earth history, including global warming due to excessive volcanogenic CO2 emission, acidification, ozone depletion etc., which in turn have been perceived important killing mechanisms of mass extinctions. However, direct evidences of the linkage between volcanism and paleoenvironmental /paleoclimatic perturbations are still lacking. The Triassic-Jurassic transition (~ 201 Ma) saw one of the most catastrophic volcanic eruptions during the Phanerozoic, namely the Central Atlantic Magmatic Province (CAMP) and it has been suggested to have triggered a series of environmental/climatic perturbations which eventually caused the end-Triassic mass extinction. However, due to the lack of volcanic ash sediments outside its eruption sites, the spatial extent to which the volcanism has had impact on is not well understood. Recently, researchers from China University of Geosciences (Wuhan), Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), together with other institutions from USA, have reported elevated Hg concentrations and isotopes from terrestrial sediments of two sites in the Junggar Basin and the Sichuan Basin in China, which are spatially distant from the CAMP and interpreted them as direct evidences of intense volcanism in association with CAMP. This study was published online in the journal Nature Communications. Besides, these researchers also reported pronounced elemental and clay mineralogical changes at the same level as the elevated Hg concentrations and interpreted these changes as solid signs of enhanced weathering intensity of sediment sources. Resultantly, the researchers then suggested a causal link between intensified volcanisms and chemical weathering of sediments during that time. "Our work is the first to show direct linkage between intensified volcanism and immediate weathering response outside of the CAMP sites during that critical time interval in Earth history," Prof. WANG Yongdong says. With the help of previous time framework established by astronomical cycles, the researchers found out that the impact of volcanism on weathering has lasted for ~ 2 million years, which is consistent with their modelling results. Altogether, these researchers suggested that chemical weathering of rocks on land may have been an important method Mother Earth adopted to draw down excess CO2 in the atmosphere in order to maintain relatively stable climatic conditions on the Earth surface ecosystems. Also by comparing the amplitude of the enhancement of chemical weathering conditions between the two study sites which occupied a high and a low paleolatitudes respectively, those researchers also concluded that chemical weathering responded more pronouncedly in the higher latitudes than in the low latitudes at that time during the eruption of the CAMP. Reference: Jun Shen*, Runsheng Yin, Shuang Zhang, Thomas J. Algeo, David J. Bottjer, Jianxin Yu*, Guozhen Xu, Donald Penman, Yongdong Wang*, Liqin Li, Xiao Shi, Noah J. Planavsky, Qinglai Feng, Shucheng Xie, 2022. Intensified continental chemical weathering and carbon cycle perturbations linked to volcanism during the Triassic-Jurassic transition. Nature Communications, 13, 299. https://www.nature.com/articles/s41467-022-27965-x. Fig.1 Geobal paleogeography of the Late Triassic (~200 Ma). Yellow stars represent the study sites, including The Haojiagou section (~60°N, high latitude) on the North China Craton, and the Qilixia section (~30–40°N, low/middle latitude) on the South China Craton. Circles and squares represent other marine and continental sections, respectively.
Fig.2. Geological sections of the Haojiagou in Junggar Basin of Xinjiang (Upper) and the Qilixia in the Sichuan Basin (Lower), China
Fig. 3. Profifiles of the Haojiagou (Upper, HJG) and Qilixia (Lower, QLX) sections, showing the Organic carbon isotope (δ13Corg, ‰), Mercury concentrations (Hg, ppb), Ratios of mercury to total organic carbon (Hg/TOC, ppb/wt %), Chemical index of alteration (CIA) and clay minerals. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Angiosperms may be distinguished from their gymnosperm peers bytheir flowers,and thus a flower is a good proxy of fossil angiosperms. However, flowers and their parts are usually too frail to be preserved in the fossil record. This makes the origin of angiosperms and their flowers the foci of controversy in botany. Angiosperms may be distinguished from their gymnosperm peers by their flowers, and thus a flower is a good proxy of fossil angiosperms. However, flowers and their parts are usually too frail to be preserved in the fossil record. This makes the origin of angiosperms and their flowers the foci of controversy in botany. Eliminating such botanical controversies can only be achieved by studying related plant fossils. Recently, Prof. WANG Xin from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with scientists from South China Agricultural University, document a fossil flower bud, Florigerminis jurassica gen. et sp. nov., from the Jurassic of Inner Mongolia, China. This is the earliest fossil record of flower buds in the world so far. Their findings were published by The Geological Society of London. WANG Xin says, "this fossil includes not only a leafy branch but also physically connected fruit and flower bud." The developmentally interpolated existence of a blooming flower between the flower bud and mature fruit in Florigerminis suggests that angiosperm flowers were present in the Jurassic, in agreement with recent botanical progress. Previous plant fossils were often preserved fragmentarily, leading paleobotanists to consider them as belonging to different plants. This Florigerminis jurassica underscores the presence of angiosperms in the Jurassic and demands a rethinking of angiosperm evolution. This research was supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Da-Fang Cui, Yemao Hou, Pengfei Yin, Xin Wang, 2022. A Jurassic flower bud from China. Geological Society, London, Special Publications, 521, https://doi.org/10.1144/SP521-2021-122.
Florigerminis jurassica gen. et sp. nov and its details
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Alienopteridae were originally proposed as a new insect order (Alienoptera) in 2016, and this family was considered as one of the most peculiar insects in Burmese amber. Alienopteridae were originally proposed as a new insect order (Alienoptera) in 2016, and this family was considered as one of the most peculiar insects in Burmese amber. Firstly, Alienopteridae were only discovered from mid-Cretaceous Burmese amber, but later few specimens were also reported from the Lower Cretaceous Crato Formation of Brazil and the middle Eocene Green River Formation of the USA. However, the life history, systematic position, and taxonomic status of Alienopteridae (Alienoptera) have been much disputed since the group was established. Recently, LUO Cihang, a postgraduate student, supervised by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with other scientists from NIGPAS, discovered many new specimens of Alienopteridae from the museum and/or Institute of China, Germany, USA and Slovakia. This study was published in Earth-Science Reviews on Dec. 30, 2021. The team used an array of different methods, i.e., optical microscopy, confocal laser scanning microscopy (CLSM), x-ray microcomputed tomography, geometric morphometric analysis and phylogenetic analysis to evaluate the morphology, life habits and evolutionary history of Alienopteridae. "We discovered that one alienopterid nymph is laden with gymnosperm pollen grains," WANG Bo says. Therefore, by providing the first possible direct evidence of gymnosperm pollination by a fossil dictyopteran, researchers may confirm a previously unknown gymnosperm-insect association. This is the only known fossil pollination example from the Polyneoptera, one of the major lineages of winged insects and indicated that some Mesozoic dictyopterans may have been important pollinators of gymnosperm. The order Aethiocarenodea was erected using an isolated specimen from mid-Cretaceous Kachin amber and was considered as one of the most enigmatic insects in Burmese amber. This study is based on morphological observations and summaries of a large number of specimens, confirmed that Aethiocarenodea is actually a specialized type of alienopterid nymphs, and finally revised the systematic position of Aethiocarenodea. The researchers also carried out a phylogenetic analysis based on a matrix with 56 characters and 39 terminals, which evaluated the phylogenetic placement and evolution history of Alienopteridae. There have robust evidences that the Alienopteridae is a specialized taxon of Dictyoptera, sister to Umenocoleidae, and Alienopteridae alone should not be ranked as a separate order. Hence, the two families should be combined as clade Alienoptera and placed as sister to Mantodea. They probably arose before the J/K boundary and their common ancestor may have occurred in the Late Jurassic. "We also reported an alienopterid nymph fell prey to a lacewing larva." WANG says, "these discoveries provide direct evidence for us to reconstruct the Cretaceous terrestrial ecosystem and further confirm that insects already evolved complex behaviors during the Cretaceous." This research was supported by the Chinese Academy of Sciences, Ministry of Science and Technology of China and National Natural Science Foundation of China. Reference: Luo Cihang, Beutel R.G., Engel M.S., Liang Kun, Li Liqin, Li Jiahao, Xu Chunpeng, Vr？ansky P., Jarzembowski E.A., Wang Bo, 2021. Life history and evolution of the enigmatic Cretaceous–Eocene Alienopteridae: A critical review. Earth-Science Reviews. https://doi.org/10.1016/j.earscirev.2021.103914.
alienopterid nymphs and gymnospermous pollen grains Monosulcites
Phylogeny of Alienopteridae (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
Myrmecomorphy is a phenomenon in which some animals mimic ants morphologically and behaviorally, and belongs to a special kind of anthropomorphic behavior, which is very widely distributed in nature. Myrmecomorphy is a phenomenon in which some animals mimic ants morphologically and behaviorally, and belongs to a special kind of anthropomorphic behavior, which is very widely distributed in nature. Recently, LUO Cihang, a postgraduate student, supervised by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), collaborated with other scientists from NIGPAS, discovered a new type of alienopterid nymphs from mid-Cretaceous Burmese amber. The discovery indicated that the earliest ant mimicry has already existed in mid-Cretaceous, thereby extending its geological range by approximately 50 million years. This study was published in Earth-Science Reviews on Dec. 30, 2021. More than 2000 living species of insects and spiders, representing 11 different arthropod orders, has evolved at least 30 times among arthropods. However, the fossil record of myrmecomorphy is extremely sparse and researchers know little about its origin and evolution. By using quantitative geometric morphometric analysis, researchers discovered that the body shape of these alienopterid nymphs is very close to sphecomyrmine ant (a kind of extinct ants). Moreover, the shape of the antennae and legs of these alienopterid nymphs and ants are close and the ratios of the antennae and legs to the body length are approximately the same as in some sphecomyrmine ants. "We discovered a new type of alienopterid nymphs and provided new evidence for the early evolution of ant mimicry." WANG says, "we also concluded that these nymphs adults were likely wasp mimics, therefore, we provided the first fossil record of transformational mimicry." In addition, the main progress and significances of this study also confirm wasp mimicry present in Alienopteridae adults and to report the first fossil record of transformational mimicry. Researchers confirmed that thoraco-abdominal waist-like constrictions of some alienopterid adults (adults of those ant mimics) resemble Hymenoptera. Additionally, the strongly shortened forewings of some alienopterid adults closely resemble the tegulae of Hymenoptera and the hind wing structurally similar to hymenopteran wings. Moreover, the body shape and size of some alienopterid adults are similar to some large aculeate Hymenoptera from the same deposit, especially ampulicid wasps. Interestingly, the nymphs and adults of the mid-Cretaceous alienopterid imitate entirely different hymenopteran models, and therefore probably provide the first fossil record of transformational mimicry (mimicking different organisms during their postembryonic development). This research was supported by the Chinese Academy of Sciences, Ministry of Science and Technology of China and National Natural Science Foundation of China. WU Suping from NIGPAS provided technical support for Micro-CT. We also thank Mr. HUANG Yiren and Mr. XIA Fangyuan for providing part of specimens. Reference: Luo Cihang, Beutel R.G., Engel M.S., Liang Kun, Li Liqin, Li Jiahao, Xu Chunpeng, Vr？ansky P., Jarzembowski E.A., Wang Bo, 2021. Life history and evolution of the enigmatic Cretaceous–Eocene Alienopteridae: A critical review. Earth-Science Reviews. https://doi.org/10.1016/j.earscirev.2021.103914 Fig. 1 Representative taxa of Alienopteridae and Umenocoleidae. Fig. 2 Reconstruction drawings of Alienopteridae (Image by LI Jiahao). Fig. 3 Alienopterid nymphs and ants, ants marked with M (Image by NIGPAS). Fig. 4 Ecological reconstruction of Alienopteridae (Image by YANG Dinghua). A: Ecological reconstruction of alienopterid nymphs; the brown insect at left with two cerci are alienopterid nymphs, the other three brown insects are ants. B: Ecological reconstruction of alienopterid adults.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
During the Late Permian to Early Triassic, benthic marine redox conditions in the Shangsi area varied on both short-term and long-term time scales. This study has scientific implications for revealing the spatial and temporal distribution of anoxic events, and the importance of oceanic anoxia in the end-Permian mass extinction (EPME). During the Late Permian to Early Triassic, benthic marine redox conditions in the Shangsi area varied on both short-term and long-term time scales. This study has scientific implications for revealing the spatial and temporal distribution of anoxic events, and the importance of oceanic anoxia in the end-Permian mass extinction (EPME). About 252 million years ago, more than 81 percent of animal life in the oceans and 89 percent of animal life on land went extinct. Extensive volcanism (the Siberian large igneous province magmatism and felsic volcanism in South China) is the most probable trigger of this life crisis. Oceanic/marine anoxia triggered by volcanisms is the most plausible killing mechanism for the EPME in the marine realm. Although a wealth of studies had supported the latest Permian-Griesbachian extreme anoxia, there is some opposite evidence indicating the occurrence of oxic benthic marine conditions during the Permian-Triassic interval. In addition, it has been reported that the deterioration of the marine environment was probably before the EPME. However, compared to a vast number of studies on the Permian-Triassic interval, only a few studies focusing on the paleo-oxygen levels during the Late Permian have been conducted. Therefore, further work needs to be carried out on the benthic marine redox conditions before and during the EPME. Recently, Dr. ZHENG Quanfeng, Prof. ZHANG Hua, WANG Yue, and CAO Changqun from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NGIPAS), collaborating with researchers from China University of Mining and Technology and Nanjing University, made high-resolution sedimentological and ichnological studies to reveal benthic marine redox conditions and driving mechanisms from Late Permian to the earliest Triassic at Shangsi, South China. This study was published in Earth-Science Reviews on Dec. 20. "We found that high-frequency (centimeter- to decimeter-scale) and secular (meter- to tens of meters-scale) benthic oxygen-level variations were developed at Shangsi", Dr. ZHENG says. The high-frequency variations were mostly local signals generated by transient episodic mixing and ventilation by storms and turbidity currents. While the secular variations were regional or global signals caused by regional factors and global climate changes. Anoxic/euxinic benthic marine conditions prevailed throughout the middle Wuchiapingian to the early Changhsingian at Shangsi, which persisted for 3.9 Myr (256.974–253.073 Ma). This long-term Wuchiapingian anoxia event can be correlated both regionally and globally, and was caused by paleogeographic restrictions, relative high sea levels, high marine productivities, and possible global climate changes. "In addition, we found a long-term global oxygenation event occurred during the Changhsingian, which initiated at ~253.513 Ma, followed by a major oxygenation pulse at 253.073 Ma, and further intensified at 252.739 Ma at Shangsi." This Changhsingian global oxygenation event was probably triggered by an early Changhsingian global cooling event, during which the average surface ocean temperature declined ~6 ℃, and the cold climate persisted during most of the Changhsingian. This research was supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Zheng, Q.F.*, Zhang, H., Yuan, D.X., Wang, Y., Wang, W.Q., Cao, C.Q., Shen, S.Z., 2022. High-resolution sedimentology, ichnology, and benthic marine redox conditions from Late Permian to the earliest Triassic at Shangsi, South China: Local, regional, and global signals and driving mechanisms. Earth-Science Reviews, 225: https://doi.org/10.1016/j.earscirev.2021.103898. Table 1 Summary of characteristics used to define redox conditions during deposition Conditions MBD (mm) ii Sedimentary fabric Oxygen (ml/l) Euxinic/anoxic 0 1 Well laminated; no sighs of biogenic structures. 0 (H2S) suboxic 0-5 2-4 Well to faintly discontinuously laminated; partly bioturbated. 0-0.15 Lower dysoxic 0-5 5-6 Completely bioturbated or homogenized. 0.15-0.5 Upper dysoxic/oxic 5-10 5-6 Completely bioturbated or homogenized. ≥0.5 Oxic ≥10 5-6 Completely bioturbated or homogenized. ≥2.0
Fig. 1. Lithofacies, microfacies, and storm-induced structures (A, C-E) from the top Wuchiaping Formation (A and B) and the basal Talung Formation (C-G). (Image by NIGPAS) Fig. 2. Late Permian to the earliest Triassic stratigraphic distribution of conodont zones (CZ), ichnocoenoses (Ichnoc.), sedimentological log, U–Pb ages, ichnofabirc index (ii), maximum burrow diameter (MBD), redox interval (RI), redox-condition column (RC), secular ichnofabric index (s-ii), secular maximum burrow diameter (s-MBD), secular redox-condition column (sRC), astronomical ages (AA), eccentricity cycles (E) proxied by anhysteretic remanent magnetization (ARM), and relative sea level (RSL) at the Shangsi section. The U–Pb ages are from Shen et al. (2011); the ARM data is from Wu et al. (2013). (Image by NIGPAS) Fig. 3. Driving factors for the evolution of benthic-marine redox conditions at Shangsi from the Lopingian to the earliest Triassic. (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
The Lantian biota, discovered from the Ediacaran basinal-facies deposition of the Lantian Formation near Lantian Town of the Anhui Province, South China, yields an assemblage representing one of the oldest known complex macrofossils. These fossils are preserved on the bedding surface of black shales in the middle part of the Lantian Formation, and their age was estimated at approximately 600 Ma. The Lantian biota, discovered from the Ediacaran basinal-facies deposition of the Lantian Formation near Lantian Town of the Anhui Province, South China, yields an assemblage representing one of the oldest known complex macrofossils. These fossils are preserved on the bedding surface of black shales in the middle part of the Lantian Formation, and their age was estimated at approximately 600 Ma. The Chuaria fossils usually with spheroidal or disk-like shapes, are the most common macrofossils in the Lantian biota. Although great majority of the Lantian Chuaria fossils are preserved as carbonaceous compressions, Chuaria has been reported to be commonly preserved as pyritization enveloped by aluminosilicate minerals in the upper Member II of the Lantian Formation. The outer minerals that envelope the pyrite layer have been assigned to quartz or aluminosilicate clay minerals. However, their exact mineral compositions as well as whether these minerals have contributed to the exceptional preservation of Ediacaran Lantian Chuaria remain unclear. Dr. WANG Wei and her research group from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) employed light microscopy, field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and Raman spectroscopy techniques to revisit the preservation of pyritized Chuaria from the Lantian biota. "Our taphonomic experiments show Chuaria fossil pyritization occurs at early fossilization process and has contributed to the soft-tissue preservation." Wang says. "The pyritization process is probably divided into at least two stages, which are characterized by distinct pyrite crystal morphologies." The pyritized Chuaria fossils are enveloped by platy minerals that are a complex mixture of quartz and magnesium-rich aluminosilicates. Integrated mineral and structural pattern analyses show that these quartz and clay minerals are both secondary overgrowth on Chuaria internal mold, which probably formed as a diagenetic product concurrent with carbonate dissolution in the Lantian black shales. Their formation is probably regulated by local micro-environment near the Chuaria bodies. These enveloped minerals may facilitate preservation and identification of Chuaria fossils, but they are probably not involved in the initial fossilization process as the early diagenetic pyritization has done. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Science and Technology Research Project for the Research Institute of Petroleum Exploration and Development, CNPC. Reference: Wang Wei*, Guan Chengguo, Zhao Xianye, Fang Yan, Zhou Chuanming, Yuan Xunlai (2022) Taphonomic study of Chuaria fossils from the Ediacaran Lantian biota of South China. Precambrian Research, 369: 106529. https://doi.org/10.1016/j.precamres.2021.106529. Fig. 1 Images of the Chuaria fossils
Fig. 2 Elemental mapping and Raman spectroscopic investigations on platy minerals Fig. 3 A simplified cartoon showing Chuaria fossilization process
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
