The Baoshan region (Sibumasu Terrane) of Yunnan Province, SW China, is one of the best locations to study the Wenlock to Pridoli conodonts in China. Conodont fauna of the “Lichaiba” and Niushiping formations were preliminarily reported during the IGCP 591 Field Meeting in 2014. The Baoshan region (Sibumasu Terrane) of Yunnan Province, SW China, is one of the best locations to study the Wenlock to Pridoli conodonts in China. Conodont fauna of the "Lichaiba" and Niushiping formations were preliminarily reported during the IGCP 591 Field Meeting in 2014. Recently, a more detailed analysis of conodont collections from the Silurian strata of the Laojianshan section in the Baoshan region was carried out by Dr. CHEN Zhongyang, Prof. WANG Chengyuan and their colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), together with Dr. Peep Mannik from Tallinn University of Technology. A revised dating of the section is provided based on the conodont biostratigraphy. The results have been published online in Geological Journal. In stratigraphically ascending order, the Pterospathodus amorphognathoides amorphognathoides Zonal Group, the Pterospathodus pennatus procerus Superbiozone, the Ozarkodina sagitta sagitta Biozone, the Kockelella ortus absidata Biozone, the Kockelella crassa Biozone, the Polygnathoides siluricus Biozone and the "Ozarkodina" eosteinhornensis s.l. Interval Biozone were recognized. Several landslides were also recognized, especially two major landslides which cover the base of the "Lichaiba" and Niushiping formations respectively. The conodont faunas recovered indicate that the "Lichaiba Formation" corresponds to the upper Telychian–upper Wenlock, and the Niushiping Formation to the Ludlow–Pridoli. Part of the Ireviken Event, that is, from Datum 3 to Datum 4 can be recognized from the studied section. The late Telychian conodont fauna from the Laojianshan section is characteristic of distal, open-shelf depositional environments. This research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Science and Technology Major Project of China, the State Key Laboratory of Palaeobiology and the Eesti Teadusagentuur. This is also a contribution to the IGCP Project 652 'Reading geologic time in Paleozoic sedimentary rocks'. Reference: Chen, Z.Y., Mannik, P., Wang, C.Y.*, Fang, X., Chen, T.E., Ma, X., Zhang, Y.D., Silurian conodont biostratigraphy of the Laojianshan section, Baoshan, Yunnan Province, SW China. Geological Journal. https://doi.org/10.1002/gj.3813 Range chart of conodont species from the Laojianshan section Conodonts from the "Lichaiba" Formation
Among the earliest fossil ants known, haidomyrmecine ‘hell ants’ from Cretaceous amber reveal an ancient and dramatic early burst radiation of adaptive forms. These eusocial Cretaceous taxa diverged from extant lineages prior to the most recent common ancestor of all living ants and possessed bizarre scythe-like mouthparts along with a striking array of horn-like cephalic projections. Despite the morphological breadth of the fifteen thousand known extant ant species, phenotypic syndromes found in the Cretaceous are without parallel and the evolutionary drivers of extinct diversity are unknown. Among the earliest fossil ants known, haidomyrmecine ‘hell ants’ from Cretaceous amber reveal an ancient and dramatic early burst radiation of adaptive forms. These eusocial Cretaceous taxa diverged from extant lineages prior to the most recent common ancestor of all living ants and possessed bizarre scythe-like mouthparts along with a striking array of horn-like cephalic projections. Despite the morphological breadth of the fifteen thousand known extant ant species, phenotypic syndromes found in the Cretaceous are without parallel and the evolutionary drivers of extinct diversity are unknown. Now, an international research group from U.S., France, and China has proposed a mechanistic explanation for aberrant hell ant morphology, and thus providing new insight into the evolution of hell ants. The research was co-led by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology (NIGPAS) of the Chinese Academy of Sciences. Results were published in Current Biology on August 6. The researchers have provided a mechanistic explanation for aberrant hell ant morphology through phylogenetic reconstruction and comparative methods, as well as a newly reported specimen. They reported a remarkable instance of fossilized predation that provides direct evidence for the function of dorsoventrally-expanded mandibles and elaborate horns. These findings confirmed the hypothesis that hell ants captured other arthropods between mandible and horn in a manner that could only be achieved by articulating their mouthparts in an axial plane perpendicular to that of modern ants. The head capsule and mandibles of haidomyrmecines are uniquely integrated as a consequence of this predatory mode and covary across species while finding no evidence of such modular integration in extant ant groups. The results of this study suggest an extinct early burst adaptive radiation into morphospace that is unoccupied by any living taxon, triggered by an innovation in mouthpart movement and subsequent modular covariation between mandible and horn. The new results also suggest that hell ant cephalic integration – analogous to the vertebrate skull – triggered a pathway for an ancient adaptive radiation and expansion into morphospace unoccupied by any living taxon. Reference: Barden P.*, Perrichot V.*, Wang Bo* (2020) Specialized predation drives aberrant morphological integration and diversity in the earliest ants. Current Biology. https://doi.org/10.1016/j.cub.2020.06.106. Reconstructions of haidomyrmecine hell ants Phylogeny and cephalic homology of hell ants and modern lineages Morphospace and evolutionary integration of living and Cretaceous ants
Known as the third pole of the earth, the magnificent Qinghai-Xizang plateau used to be a vast ocean millions of years ago and its vicissitudes have become one of the hotspots of the geological research. Stratigraphy is the basis for diachronic reconstruction of this process, with biostratigraphy the most fundamental method and fossils often the most reliable evidence for the age of strata. However, due to extreme natural conditions and intense tectonic deformation and metamorphism, fossil collection and biostratigraphic research in the Qinghai-Xizang plateau are very difficult and the progress has been very slow. The Neo-Tethys realm in southern Xizang, as represented by the Yarlung Zangbo Suture Zone, is such a prominent sample where the Mesozoic and Cenozoic strata bear many problems and arguments, which has already become a restrict to other researches. Known as the third pole of the earth, the magnificent Qinghai-Xizang plateau used to be a vast ocean millions of years ago and its vicissitudes have become one of the hotspots of the geological research. Stratigraphy is the basis for diachronic reconstruction of this process, with biostratigraphy the most fundamental method and fossils often the most reliable evidence for the age of strata. However, due to extreme natural conditions and intense tectonic deformation and metamorphism, fossil collection and biostratigraphic research in the Qinghai-Xizang plateau are very difficult and the progress has been very slow. The Neo-Tethys realm in southern Xizang, as represented by the Yarlung Zangbo Suture Zone, is such a prominent sample where the Mesozoic and Cenozoic strata bear many problems and arguments, which has already become a restrict to other researches. Recently, Professor LI Jianguo and his colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) established a new integrated biostratigraphic framework for the Triassic–Paleogene strata in Neo-Tethyan realm in southern Xizang based on a combination of their own material and progress and other previous researches. The results have been published online in the Journal of Asian Earth Sciences, an international comprehensive journal of geology. Many blanks in biostratigraphy got filled in this framework and much progress has been made for fossils that were never or weakly studied in the past, particularly microfossils such as conodonts, radiolarians, and miospores. For those well-studied fossils, essential supplement or improvement has been made. The new framework is improved by a series of new biostratigraphic zones, many of which are well correlated with the international standard, such as those of Lower Triassic conodonts and ammonites, uppermost Triassic–Lower Jurassic ammonites, and Upper Cretaceous planktonic foraminifers and calcareous nanofossils. A total of four integrated biostratigraphic charts are compiled in units of period, all consisting of key fossils for stratigraphic division and correlation of that period, such as ammonites, conodonts, bivalves, radiolarians, foraminifers and calcareous nanofossils. Based on these biostratigraphic advances, the authors also discussed and clarified some questions or arguments on the definition, division, correlation and age of some Triassic to Paleogene strata in southern Xizang. The duration of the new integrated biostratigraphic framework is roughly the time that the Neo-Tethys Ocean evolved from its opening by the rifting of Lhasa-Gondese block from the northern margin of Gondwana to its closure as a consequence of the Indian–Eurasian collision. In this respect, this research will provide as an important stratigraphic reference for the study of the evolution of Neo-Tethys and other geological researches on the Qinghai-Xizang Plateau. The relevant research was supported by the Second Tibetan Plateau Scientific Expedition and Research, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Jianguo Li*, Miaoqin Lin, Yixiao Wu, Hui Luo, Jungang Peng, Lin Mu, Bo Xu, Chao Zhang, 2020. New biostratigraphic framework for the Triassic–Paleogene in the Neo-Tethys realm of southern Xizang (Tibet), China. Journal of Asian Earth Sciences, https://doi.org/10.1016/j.jseaes.2020.104369. The new integrated biostratigraphic charts of the Triassic-Paleogene strata in the studied area
Reefs are the most complicated and diverse ecosystems in the ocean, with highest levels of species diversity, habitat diversity, community structure and functional diversity. Therefore, they represent one of the most significant genetic treasures in the evolution of Earth life. Metazoan reef ecosystem reached its Phanerozoic acme in Givetian (Middle Devonian), however, detailed studies on the reef biodiversity, ecological interactions and community composition of Givetian reefs are still lacking, limiting our further understanding of the palaeobiodiversity change pattern and evolutionary model of reef ecosystem in critical geological time intervals. Reefs are the most complicated and diverse ecosystems in the ocean, with highest levels of species diversity, habitat diversity, community structure and functional diversity. Therefore, they represent one of the most significant genetic treasures in the evolution of Earth life. Metazoan reef ecosystem reached its Phanerozoic acme in Givetian (Middle Devonian), however, detailed studies on the reef biodiversity, ecological interactions and community composition of Givetian reefs are still lacking, limiting our further understanding of the palaeobiodiversity change pattern and evolutionary model of reef ecosystem in critical geological time intervals. Recently, a systematic study of the Givetian reef biodiversity was carried out by an international research group led by Assoc. Profs. QIE Wenkun and LIANG Kun, Mater HUANG Jiayuan from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and collaborators from Brunel University, Guizhou University and Wuhan Center of Geological Survey, China Geological Survey. Related paper has been published online in Palaeogeography, Palaeoclimatology, Palaeoecology. The team focuses on the detailed palaeontological and palaeoecological analysis of a Givetian reef located in Dushan Formation, Dahekou section, Guizhou Province, South China. In this study, 665 samples were collected in-situ in 7 m2 by 28 quadrats (50í50 cm) of the vertical reef outcrop, with 2804 thin sections being made and 10823 fossils being described. Detailed statistics of biodiversity and community paleoecology were carried out based on these large amounts of systematic data. As so far, a total of 83 species belonging to 44 genera of 8 phyla were identified within 7 m2 of the Jiwozhai patch reef, including rugose corals (29 species, 9 genera), stromatoporoids (16 species, 10 genera), tabulate corals (13 species, 9 genera), brachiopods (16 species, 8 genera), Bryozoans (4 species, 4 genera), calcified cyanobacteria (3 species, 3 genera), chaetetids (1 species, 1 genera) and tubeworms (1 species, 1 genera). Among them, stromatoporoids (N=755), tabulate corals (N=630), rugose corals (N=198) and chaetetids (N=144) are the most common organisms. Consistent with the densely distributed species at Jiwozhai, complex ecological relationships, including extensive encrustations (N=716), spatial competition (N=35) and symbiosis (N=58) have also been found among different organisms. The in-situ collection of fossils and the sketch of the reef outcrop with high density clarify the spatial distribution characteristics of the reef organisms in Middle Devonian, which shows the stability of the spatial distribution of the main reef-building organisms while the discrepancy between the secondary reef-building organisms and the reef-dwelling organisms. This study would provide important reference for the further correlation of global paleogeography and interpretation of the evolution and distribution patterns of the reef diversity during geological time. This work is financially supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences, National Natural Science Foundation of China and Geological Survey Projects of China Geological Survey. Reference: Huang, J., Liang, K.*, Wang, Y., Liao, W., Guo, W., Kershaw, S., Jeon, J., Qiao, L., Song, J., Ma, J., Li, Y., Tu, B., Tian, Y., Wang, Y., Wang, Y., Ma, J., Luo, M., Qie, W.*, 2020. The Jiwozhai patch reef: A palaeobiodiversity hotspot in middle Givetian (Devonian) of South China. Palaeogeography, Palaeoclimatology, Palaeoecology, https://doi.org/10.1016/j.palaeo.2020.109895 The Givetian Jiwozhai patch reef of Middle Devonian in Dushan, Guizhou Stromatoporoids and chaetetids in the Jiwozhai patch reef Biotic interactions among the reef organisms in the Jiwozhai patch reef Statistics of biodiversity and abundance (Frequency) of Jiwozhai reef
The Sichuan Basin is one of the most gas-productive continental basins in China, especially with the giant gas fields recently discovered in Puguang and Guang’an regions in the Sichuan Province. The terrestrial coals and mudstones of the Upper Triassic Xujiahe Formation and the Lower Jurassic Zhenzhuchong Formation represent one of the most significant hydrocarbon source rocks within the basin, especially in the western, central, and southern Sichuan Basin. In the northeastern Sichuan Basin, diverse and abundant fossils have been reported from the Xujiahe and Zhenzhuchong Formations, however, paleoenvironment and hydrocarbon significances of these fossils are still less documented, and petroleum studies and exploration of these successions remain limited. The Sichuan Basin is one of the most gas-productive continental basins in China, especially with the giant gas fields recently discovered in Puguang and Guang’an regions in the Sichuan Province. The terrestrial coals and mudstones of the Upper Triassic Xujiahe Formation and the Lower Jurassic Zhenzhuchong Formation represent one of the most significant hydrocarbon source rocks within the basin, especially in the western, central, and southern Sichuan Basin. In the northeastern Sichuan Basin, diverse and abundant fossils have been reported from the Xujiahe and Zhenzhuchong Formations, however, paleoenvironment and hydrocarbon significances of these fossils are still less documented, and petroleum studies and exploration of these successions remain limited. Recently, Dr. LI Liqin, Prof. WANG Yongdong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS), and Prof. Vivi VAJDA from the Swedish Museum of Natural History, Sweden, reported palynofacies analysis results for the first time in the Sichuan Basin, combining with thermal alteration index and geochemical data, interpreted the paleoenvironment and hydrocarbon potential of the Upper Triassic Xujiahe Formation and the Lower Jurassic Zhenzhuchong Formation in the northeastern Sichuan Basin. This result was recently published online an Elsevier international journal Palaeoworld. The palynofacies analysis results showed that, the Upper Triassic and Lower Jurassic sediments in the Sichuan Basin were dominated by phytoclasts, with less abundant palynomorphs and sparse amorphous organic matters (AOMs). Four palynofacies assemblages were identified, reflecting deposition settings in a general proximal and oxic fluvial-deltaic environment, with two distal–proximal sedimentary cycles. The prominent dominance of opaque phytoclasts within the lower Zhenzhuchong Formation may be related to frequent wildfires across the Triassic–Jurassic transition. Palynofacies data (especially the abundance of opaque phytoclasts) may reflect 400 kyr eccentricity cyclicity pattern. The periodic abundance of opaque particles in the studied section may have been caused by increased runoff in the fluvial-delta environment under obliquity cycle-controlled monsoon climate. The present study suggests high potential of palynofacies analysis for cross-regional correlation for the Mesozoic sequences. However, higher resolution palynofacies data are needed in the future, to test the mechanism how orbital cyclicity controls terrestrial sedimentary environment. The palynofacies and thermal alteration index (TAI), combined with geochemical data indicated the presence of type III kerogen in mature to post-mature phases, suggesting gas potential of the Xujiahe and Zhenzhuchong formations in the northeastern Sichuan Basin. This study provides significant implications for better understanding the paleoenvironment variations during the Triassic–Jurassic transition and the future gas exploration in this area. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, the State Key Laboratory of Palaeobiology and Stratigraphy, and the Swedish Research Council. Reference: Li L., Wang Y., Vajda V., 2020. Palynofacies analysis for interpreting paleoenvironment and hydrocarbon potential of Triassic–Jurassic strata in the Sichuan Basin, China. Palaeoworld. https://doi.org/10.1016/j.palwor.2020.04.007. Lithology, sampled horizons and palynofacies data for the Xujiahe and lower Zhenzhuchong formations at the Qilixia section in the Sichuan Basin APP ternary plots for the analyzed sediments from the Xujiahe and Zhenzhuchong formations at Qilixia Section in the Sichuan Basin
The Triassic–Jurassic (T–J) transition interval (ca. 200 Ma) is characterized by a major mass extinction, one of the five largest Phanerozoic extinctions in Earth history. Major biotic turnover occurred in both marine and terrestrial realms. Much emphasis has been placed on the marine Triassic–Jurassic successions, however, studies on the terrestrial response to this event is still limited, especially in the eastern Tethys region of eastern Asia. In the northeastern Sichuan Basin of South China, the Upper Triassic and the Lower Jurassic successions are well exposed and continuously developed, yielding diverse fossil plant remains, providing important material for exploring the continental ecosystem conditions across the T–J transition in the eastern Tethys. The Triassic–Jurassic (T–J) transition interval (ca. 200 Ma) is characterized by a major mass extinction, one of the five largest Phanerozoic extinctions in Earth history. Major biotic turnover occurred in both marine and terrestrial realms. Much emphasis has been placed on the marine Triassic–Jurassic successions, however, studies on the terrestrial response to this event is still limited, especially in the eastern Tethys region of eastern Asia. In the northeastern Sichuan Basin of South China, the Upper Triassic and the Lower Jurassic successions are well exposed and continuously developed, yielding diverse fossil plant remains, providing important material for exploring the continental ecosystem conditions across the T–J transition in the eastern Tethys. In recent decade, a research team leading by Prof. WANG Yongdong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS) has conducted a series investigations in this region. Recently, Dr. LI Liqin, Prof. WANG Yongdong from NIGPAS, Prof. Wolfram M. Kürschner from the University of Oslo, Dr. Micha Ruhl from the University of Dublin and Prof. Vivi Vajda from the Swedish Museum of Natural History, published a new study in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, which reported about palaeovegetation and palaeoclimate changes across the Triassic–Jurassic transition in the Sichuan Basin, China. A detailed palynological study was performed from the Qilixia section in Xuanhan County of the Sichuan Basin, China, spanning the Upper Triassic (Norian–Rhaetian) (Xujiahe Formation) to the Lower Jurassic (Hettangian–Sinemurian) (lower Zhenzhuchong Formation). Five palynological assemblages were identified, in combination of Principal Components Analysis (PCA) and Sporomorph EcoGroup (SEG) model, they reveal significant ecosystem fluctuations across the Triassic–Jurassic transition. The palynological analysis indicates a lowland fern flora and a warm and humid climate in the Late Triassic (Norian to Rhaetian), interrupted by a cooler interval at the Norian–Rhaetian transition, and followed by a mixed mid-storey forest under cooler and drier condition in the latest Rhaetian. This is followed by a fern-dominated lowland vegetation and a warmer and drier climate during the Triassic–Jurassic transition, and a flora with abundant cheirolepid conifers in the Hettangian–Sinemurian. Most interestingly, the significantly dominant fern vegetation at the Triassic–Jurassic transition interval is similar to the changes reported from geographically widespread sites. The short cooling at the end Triassic and preceding a period of warmer condition at the Early Jurassic, is comparable with records from the western Tethyan realm. It likely reflects (global) vegetation turnover and climatic fluctuations at this time. This global response in vegetation and climate may suggest that, the CAMP emplacement, with a significant influx of SO2 and sulphate aerosols into atmosphere, causing an initial cooling at the latest Triassic. It was later outpaced by global warming from elevated CO2 release in the Triassic–Jurassic transition interval. This study represents the best and higher resolution palynological records of the Triassic and Jurassic transition in siuthern China, providing important evidence for terrestrial ecosystem response to the Triassic–Jurassic event from the eastern Tethys area. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, the State Key Laboratory of Palaeobiology and Stratigraphy, and the Swedish Research Council. Reference: Li L., Wang Y*., Kürschner, W.M., Ruhl, M., Vajda V.*, 2020. Palaeovegetation and palaeoclimate changes across the Triassic–Jurassic transition in the Sichuan Basin, China. Palaeogeography Palaeoclimatology Palaeoecology. https://doi.org/10.1016/j.palaeo.2020.109891. Late Triassic spores and pollen representative taxa from Xuanhan of Sichuan Basin Early Jurasic spores and pollen representative taxa from Xuanhan of Sichuan Basin Late Triassic–Early Jurassic palynological assemblages and palaeovegetation reconstruction of the Sichuan Basin
Late Triassic–Early Jurassic palynoflora and palaeoclimate implications for the Sichuan Basin
The cephalopod Sinoceras chinense (Foord) is regarded as the index fossil of the Upper Ordovician Pagoda Formation on the Yangtze Platform of South China, with a likely age of early Katian. S. chinense was previously only known from the Upper Ordovician of Chinese blocks/terranes, including South China, Tarim, Tibet (Xizang) and western Yunnan. The cephalopod Sinoceras chinense (Foord) is regarded as the index fossil of the Upper Ordovician Pagoda Formation on the Yangtze Platform of South China, with a likely age of early Katian. S. chinense was previously only known from the Upper Ordovician of Chinese blocks/terranes, including South China, Tarim, Tibet (Xizang) and western Yunnan. During January 2020, an international research team lead by Dr. FANG Xiang from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and Prof. Clive BURRETT from Mahasarakham University conducted a Sino-Thai joint field trip in western Thailand. During the fieldwork, the first identification of S. chinense is confirmed. This work has been published online in Palaeoworld. These specimens were recorded in a geoconservation named “Nautiloid Site”, located in Si Sawat county of Kanchanaburi Province, western Thailand. Previously, these specimens were wrongly identified as actinocerids, which results in the misjudgments on geological time of the upper part of Tha Manao Formation. The exact identification of S. chinense suggests the upper part of Tha Manao Formation age of early Katian of Late Ordovician, providing evidence for the stratigraphic correlation between the upper part of the Tha Manao Formation in Thailand and the Pagoda Formation (and contemporaneous units) in China. Western Thailand, combined with Baoshan region of western Yunnan, was located on Sibumasu Terrane during the Early Palaeozoic. The confirmed identification of S. chinense in Thailand is the first record in Thailand and alsothe first report in a region outside of China.Moreover, the discovery of the species in the Sibumasu Terrane provides strong support for the palaeogeographic reconstruction and pronounced palaeobiogeographic changes from the Middle to Late Ordovician among the peri-Gondwanan regions. This research has been supported by CAS Strategic Priority Research Program, The Second Tibetan Plateau Scientific Expedition and Research, State Key Laboratory of Palaeobiology and Stratigraphy, Ministry of Nature and Resources of China, and Mahasarakham University. Reference: Fang, X., Li, C., Li, W.J., Burrett, C., Udchachon, M., Zhang, Y.D., 2020. Sinoceras chinense (Foord, 1888) in western Thailand: first identification outside China. Palaeowolrd. https://doi.org/10.1016/j.palwor.2020.06.004 Sinoceras chinense, collected from Si Sawat county of Kanchanabura Province, western Thaialand Distribution of S. chinense in the northeastern peri-Gondwana region
Fossil woods preserved in deposits through the process of permineralization play a crucial role in reconstructing the floristics aspects of ancient forest ecosystems and climatic conditions in deep time. Fossil woods have been widely discovered in terrestrial ecosystems from the dinosaurs ages in the Jurassic and Cretaceous. In China, the fossil woods are mainly documented in the northern China region; however, the records in southern China are relatively poor. Fossil woods preserved in deposits through the process of permineralization play a crucial role in reconstructing the floristics aspects of ancient forest ecosystems and climatic conditions in deep time. Fossil woods have been widely discovered in terrestrial ecosystems from the dinosaurs ages in the Jurassic and Cretaceous. In China, the fossil woods are mainly documented in the northern China region; however, the records in southern China are relatively poor. Recently, a new extinct species of conifer wood dated over 100 million years, i.e. Brachyoxylon zhoui was reported by a research team lead by Prof. WANG Yongdong at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and Dr. JIANG Zikun at the Chinese Academy of Geological Sciences, in conjunction with the other researchers at the Zhejiang Museum of Natural History, Shenyang Normal University, and University of Bonn in Germany. This finding was recently published in the international journal Historical Biology. The fossil wood specimen was found in the Early Cretaceous Guantou Formation (about 110 Ma) in Yongkang City of Zhejiang Province, which is anatomically different from any reported fossil woods in Zhejiang. Based on comparisons between the present fossil wood material and other relative fossil woods worldwide, a new species of the morphogenus Brachyoxylon, i.e. Brachyoxylon zhoui was established by the research team. The specific name zhoui is dedicated to Prof. ZHOU Zhiyan from Nanjing for his contributions to Palaeonbotany. The terrestrial sediments, largely deposited during the Early Cretaceous in Zhejiang, contain vertebrate fossils, such as dinosaur bones and eggs, and additionally yield abundant fossil woods. The new fossil wood material is silicified and part of the secondary xylem of the tree. The new species is characterized by distinct growth rings, a mixed type of radial tracheary pitting, araucarioid cross-field pitting, high uniseriate rays, and traumatic resin canals. The quantitative analysis of the growth ring was carried out by researchers, indicating that the forest composition was evergreen with a Leaf Retention Time (LRT) of 3–15 years. Combined with the analysis of sedimentology, palynology and paleosols, researchers assume that the Zhejiang region was dominated by a subtropical to tropical and relatively semiarid climate during the Early Cretaceous. The discovery of Brachyoxylon zhoui not only enriches the understanding of the fossil forest composition and paleoclimate but also provides the essential evidence to reconstruct the paleohabitats of dinosaurs in the Early Cretaceous of Zhejiang Province. The study was co-corresponded by Dr. JIANG Zikun at the Chinese Academy of Geological Sciences and Prof. WANG Yongdong at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, other co-authors include Dr. WU Hao at the Zhejiang Museum of Natural History, Associate Professor TIAN Ning at the Shenyang Normal University, and Ph.D. candidate XIE Aowei at the University of Bonn in Germany. This research was co-supported by the National Natural Sciences Foundation of China, the Strategic Priority Program (B) of CAS, the State Key Program for Basic Research & Development of Ministry of Science & Technology of China and the State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS). Reference: Jiang Zikun*, Hao Wu, Ning Tian, Yongdong Wang*, Aowei Xie, 2020. A New Species of Conifer Wood Brachyoxylon from South China and its Palaeoclimatic Implications. Historical Biology, https://doi.org/10.1080/08912963.2020.1755282 The anatomical structures of growth rings, radial tracheary pitting in fossil conifer wood Brachyoxylon zhoui from the Early Cretaceous in Zhejiang Province of China The anatomical structures of cross-field pitting and xylem rays in fossil conifer wood Brachyoxylon zhoui from the Early Cretaceous in Zhejiang Province of China The quantitative analysis of the growth ring and paleoclimate of fossil conifer wood Brachyoxylon zhoui from the Early Cretaceous in Zhejiang Province of China
Trace fossils are the behavioural records of ancient organisms, representing the archives of the interactions between organisms and their living substrates. As a special kind of fossil types, trace fossils may include trails, tracks, burrows and feces excreted by animals (coprolites). Trace fossils are the behavioural records of ancient organisms, representing the archives of the interactions between organisms and their living substrates. As a special kind of fossil types, trace fossils may include trails, tracks, burrows and feces excreted by animals (coprolites). The trace makers may include both skeletonized as well as soft-bodied organisms. Soft bodied organisms normally are seldom to be preserved as fossils. Hence trace fossils potentially provide more complete records of both infaunal and epifaunal organisms, thus facilitating the study of community structures and composition of ancient ecosystems. These characteristics make trace fossils as ideal agents to explore the evolution of early life on Earth, infaunal responses to environmental extremes during mass extinctions, palaeoenvironmental interpretations, and characterization and recognition of significant stratigraphical boundaries in petroleum geology. Recently, Dr. LUO Mao from Nanjing Institute of Geology and Palaeontology , Chinese Academy of Sciences (NIGPAS) collaborated with Prof. SHI Guangrong and Dr. Lee Sangmin from University of Wollongong, Australia, had discovered a new trace fossil assemblage dominated by a potential bivalve trace (Parahaentzschelinia) from the Lower Permian Snapper Point Formation, which records deposition in a storm-influenced delta front environment. Related research results have been published in Palaeogeography Palaeoclimatology Palaeoecology. The dense populations of Parahaentzschelinia trace occurred in two sections, forming stacked Parahaentzschelinia ichnofabrics. Researchers interpreted these ichnofabrics as equilibrium structures, which reflect the trace maker actively adjust their living positions in response to the shifted sediment-water interface, in seeking to remain in an optimal (equilibrium) living position with the local hydrodynamic and depositional conditions (e.g., increased sedimentation or periodic erosion). The trace Parahaentzschelinia is an irregular, funnel-shaped burrow with multiple mud and sand-filled tubes radiating vertically or obliquely upward to the sediment surfaces. Distinct meniscate fills composed of alternating sand and mud laminae are characteristic of nearly all tubes, which are superimposed laterally and vertically. These dense, irregular funnel-shaped burrows may be produced by tellinid-like bivalves based on observations on the metabolic behaviour and burrow morphologies of modern tellinids. According to Dr. LUO Mao, the meniscate fills in Parahaentzschelinia isp. may be the result of successive movements of the siphons, leaving alternating sand and mud laminae. Statistical analysis of burrow lengths and numbers of burrow adjustments suggests up to seven sequences of sediment accumulation events, supplying 3–13 cm thick clastic deposits at each time. A conservative sedimentation rate of 0.24 cm/year was estimated on the basis of two stacked Parahaentzschelinia ichnofabrics and the probable maximum lifespan of modern tellinid genus. This rate is generally comparable to those derived from modern deltaic environments, lending further support to the interpretation that the ichnofabrics were formed in and characteristic of a deltaic setting. The research highlights the utility of stacked equilibrium structures as a sensitive indicator of certain depositional regimes, and its applicability for assessing sedimentation rates as well as depositional conditions in the geological past. The research has been jointed supported by the Strategic Priority Research Program of Chinese Academy of Sciences, the CAS Talents Program, the National Natural Science Foundation of China, and an Australian Research Council. Reference: Luo M*., Shi, G.R*., Lee, S., 2020, Stacked Parahaentzschelinia ichnofabrics from the Lower Permian of the southern Sydney Basin, southeastern Australia: Palaeoecologic and palaeoenvironmental significance. Palaeogeography, Palaeoclimatology, Palaeoecology 541, 109538. doi.org/10.1016/j.palaeo.2019.109538 Intergated section logs of the studied sections at Pretty Beach south (left) and O’Hara Island (right), which both represent the lower part of the Snapper Point Formtion in the southern Sydney Basin Densely occurred Parahaentzschelinia from the section at O’Hara Island. A, Parahaentzschelinia isp. recording sequence of event sedimentation layers. Black arrows indicate individual Parahaentzschelinia isp.. B, Schematic artwork showing the re-adjustments of Parahaentzschelinia to episodic sediment deposition in A
The end-Permian Mass Extinction (EPME) is widely considered to record the largest biodiversity loss coupled with the most severe ecological impact in Earth history. More than 90% of the marine species were killed in less than 200 000 years. In the aftermath of this catastrophe, the Early Triassic was characterized by large, frequent fluctuations in carbon isotopes, extremely high sea-surface temperatures, and widespread anoxic conditions, and even oceanic acidification in the global oceans. The subsequent marine biotic recovery in the Early Triassic has been delayed for a prolonged interval of around 6 million years due to persistent warming and anoxia. The end-Permian Mass Extinction (EPME) is widely considered to record the largest biodiversity loss coupled with the most severe ecological impact in Earth history. More than 90% of the marine species were killed in less than 200 000 years. In the aftermath of this catastrophe, the Early Triassic was characterized by large, frequent fluctuations in carbon isotopes, extremely high sea-surface temperatures, and widespread anoxic conditions, and even oceanic acidification in the global oceans. The subsequent marine biotic recovery in the Early Triassic has been delayed for a prolonged interval of around 6 million years due to persistent warming and anoxia. Studying the biotic recovery after the biggest mass extinction would help us understand the responses and evolutionary mechanism of ecosystems through extreme environmental changes, but also give implications to the management of modern marine ecosystems under global environmental change as those abovementioned environmental extremes are adversely affecting the livelihood of marine organisms. The impact of the EPME on behavioural aspects of the infauna, as reflected in the global abundance and diversity of trace fossils, is less explored. In many instances, trace fossils represent the behavioural records of soft-bodied organisms that have null to very limited preservation in the fossil record. They often supply vital ecological information on ancient communities not available from body-fossil documentations. In order to better understand the behavioural responses of trace makers to environmental perturbations, Dr. LUO Mao and his collaborators including Prof. Luis A. Buatois from University of Saskatchewan, Prof. SHI Guangrong from University of Wollongong, and Prof. CHEN Zhongqiangfrom China University of Geosciences (Wuhan) has compiled a global Permian？Triassic trace-fossil database. The research aims to give a comprehensive review of long-term ichnodiversity and ichnodisparity changes following the EPME, and assess how infaunal organisms behaved in response to the extinction crisis and during the biotic recovery intervals. The results have been published online in the GSA Bulletin, an international comprehensive geology journal. The study, led by Dr. LUO Mao, has depicted the global ichnodiversity and ichnodisparity change from late Permian to Middle Triassic comprising twelve time slices. Importantly, they found that global ichnodiversity and ichnodisparity maintained their pre-extinction level after the end-Permian mass extinction. In particular, late Permian global ichnodiversity and ichnodisparity maintained their level until the Griesbachian, followed by a sharp loss in the Dienerian stage. This result in diversity of trace fossils is in contrast to that of body fossils. A further analysis of the tiering composition of ichnogenera from each time slices showed that Early Triassic trace fossils are dominated by shallower tiered ichnogenera when compared with pre- and post-extinction trace fossil compositions. Furthermore, such difference in tier composition is statistically obvious. Dr. LUO Mao and his collaborators interpreted that such global ichnodiversity change might have be a taphonomic effect caused by the wide-spread occurrence of microbial mat substrate during the Early Triassic. The development of firm substrates enhanced by microbial mat enveloping, aiding the preservation of shallow-tiered trace fossils, and maintaining the high ichnodiversity level in the earliest Triassic. The dataset, and the ichnodiversity trends revealed by Dr. LUO Mao and his collaborators suggested that the high ichnodiversity and ichnodisparity in the earliest Triassic is best explained as a taphonomic artifact. The sustained high ichnodiversity in the Griesbachian, combined with the preferential occurrence of shallow-tier bioturbation structures suggests limited mixing of seafloor sediments, which have drawn parallels with substrate conditions proposed for Ediacaran-Fortunian strata. The research has been jointed supported by the Strategic Priority Research Program of Chinese Academy of Sciences, the CAS Talents Program, and the National Natural Science Foundation of China. Reference: Luo, M*., Buatois, L.A., Shi, G.R., Chen, Z.Q., 2020. Infaunal response during the end-Permian mass extinction. https://doi.org/10.1130/B35524.1. Line chart diagram summarizing variation in global ichnodiversity (a) and ichnodisparity (b) in comparison with the global generic richness of body fossils (c) Change in ichnofossil tiering levels from late Permian to Middle Triassic expressed as area plots Box plots comparing the percentage of different tiering groups between Early Triassic and pre- (late Permian) and post-extinction (Middle Triassic) intervals General trend of relative abundance of microbialites in the Lower–Middle Triassic
