This study investigated two Mid-Ordovician shale-dominated successions from the intra-shelf basin (Zhenjin section) and slope (Anye-1 core) settings of the Yangtze Sea in South China, with a novel combination of iron speciation, trace metals, bulk δ15N and pyrite δ34S (Fig. 1). And, for the first time, δ98Mo profile was produced for the Mid-Ordovician black shale in South China. The Ordovician is a critical transition for the coevolution of life and environments, as it witnessed stepwise rise of atmospheric O2 and secular decline of CO2, as well as the blooming of marine fauna and the colonization of early land plants. Herein the rapid increase in diversity and complexity of ecosystem was defined as “Great Ordovician Biodiversification Event” (GOBE), for which several triggers have been proposed including climatic cooling, atmospheric oxygenation, sea level rise and even asteroid breakup. However, the biotic overturn following the peak of GOBE and its causes warrant further investigation. Recent literature by Dr. ZHANG Junpeng and Prof. ZHANG Yuandong from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Prof. Timothy W. Lyons from University of Calofornia (Riverside) and Prof. Thomas J. Algeo from University of Cincinnati proposes that remarkable expansion of seafloor anoxia during the climatic cooling accounted for such profound biotic change, which has been published on the journal of Earth and Planetary Science Letters. This study investigated two Mid-Ordovician shale-dominated successions from the intra-shelf basin (Zhenjin section) and slope (Anye-1 core) settings of the Yangtze Sea in South China, with a novel combination of iron speciation, trace metals, bulk δ15N and pyrite δ34S (Fig. 1). And, for the first time, δ98Mo profile was produced for the Mid-Ordovician black shale in South China. The Anye-1 core yields a negative shift in δ15Nbulk upwards and low values ~ 1-2‰ (same for Zhenjin section) across the Darriwilian to Sandbian boundary, implying a gradual dominance of microbial N-fixation in the oceans (Fig. 1 and 2A). That consists with the moderate-high primary productivity and dysoxic-anoxic bottom-water conditions. While the iron proxy and δ34S reveal a progressive evolution of bottom-water redox conditions from oxic, ferruginous to euxinic in the slope of Yangtze Sea (Fig. 1, Interval I~IV). Similarly, the co-variation of enriched Mo and U indicates predominantly euxinic bottom-waters for the late Darriwilian to early Sandbian (Fig. 2B). Moreover, moderate Mo/TOC (~18 ppm/%) suggests semi-restricted watermass conditions for the Yangtze Sea (Fig. 2C). Thus, if the euxinic sediments of Ningkuo shale captured global seawater compositions, modeling reconstructed δ98MoSW of ~0.8-1.1‰, which is close to previous estimates for Ordovician seawater (1.1-1.3‰) and suggests that the oceans were less oxygenated, at least for Mid-Late Ordovician, than previously assumed. Notably, equivalent black shales of wide distribution on other continents include Saergan Formation in Tarim, Wulalike Formation in North China, Roadriver Group in Northwestern Laurentia and Alum Shale in Baltica. Those shales formed in the low-latitude continental basins that were easily influenced by upwelling. Similar to modern, during the climatic cooling, high-latitude deep and cold currents would have gotten strengthened and brought more nutrients into low-latitude shelves via upwelling. Under such scenario, more efficient nutrient cycling would stimulate primary production in the ocean surface and export massive organic carbon downwards to the seafloor, where the organic matter would get decomposed largely consuming dissolved oxygen and thus cause bottom-water anoxia. In pace with those environmental changes, the biodiversity yields a ~50% decline of species (South China, Fig. 3). Although the timing for the peak of GOBE is different for several continents, the overturn is considered to have appeared before the late Darriwilian. Therefore, climatic cooling and concurrent expansion of seafloor anoxia can be proposed as a fundamental trigger for the biotic crisis, which provides important evidence for the biotic overturn following the peak of GOBE and valuable implications for the link between icehouse ages and biotic extinctions in Earth history. This work is financially supported by Chinese Academy of Sciences, National Natural Science Foundation of China, Natural Science Foundation of Jiangsu Province, Ministry of Science and Technology of China, NASA Astrobiology Institute of USA. Analyses involved with this study were completed with the help of the State Key Lab, China University of Geosciences (Wuhan), Guiyang Institute of Geochemistry, Chinese Academy of Sciences and University of California (Riverside). Reference: Zhang, J.P.*, Li, C., Fang, X., Li, W.J., Deng, Y.Y., Tu, C.Y., Algeo, T.J., Lyons, T.W. and Zhang, Y.D., 2022. Progressive expansion of seafloor anoxia in the Middle to Late Ordovician Yangtze Sea: Implications for concurrent decline of invertebrate diversity. Earth and Planetary Science Letters, 598, p.117858. https://doi.org/10.1016/j.epsl.2022.117858. Fig.1 Geochemical profiles for Zhenjin section and Anye-1 core. Fig.2 Cross plots of proxies (A, B and C) and modeling results for seawater δ98Mo (D). Fig.3 Integrated framework of the change in climate, marine environment and biodiversity during Mid-Late Ordovician.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
How precipitation in the paleotropical belt would react to changes in paleoclimate during the late Paleozoic is not well understood. The late Paleozoic Ice Age (LPIA) was the longest-lived icehouse of the Phanerozoic and the only geological archive that recorded a permanent icehouse-to-greenhouse turnover on a planet with complex terrestrial ecosystems and metazoan life. Recently, the LPIA has been widely studied especially regarding the temporal and spatial distribution of glaciers on high-latitude regions, the causes for the onset and demise of glaciation, correlations and feedbacks among various components of the Earth system, and influences on biodiversity variations. The water cycle in response to the evolution of LPIA is, however, rarely studied, except for numerical modeling Paleoclimate simulations suggested a coupled relationship between Gandwanan ice volume and paleotropical climate dynamics on a multitude of timescales. General circulation models of the LPIA show that increased ice volume would intensify the Intertropical Convergence Zone (ITCZ) and resultant paleotropical precipitation. In contrast, climate simulations also indicate that increased precipitation in the tropical region would come along with atmospheric pCO2 and temperature rise. How precipitation in the paleotropical belt would react to changes in paleoclimate during the late Paleozoic is not well understood. The South China Block was dominated by a stable carbonate platform environment during the middle to late Paleozoic (Fig. 1). In addition, the South China Block was situated near the paleoequator in isolation during the late Paleozoic until it collided with the North China Block in the Late Permian to Early Triassic. Hence, the South China Block was free of significant tectonic activities during the late Paleozoic Recently, an integrated sedimentological and biostratigraphic study on a late Carboniferous mixed carbonate-siliciclastic succession (Fig. 2) from the southeastern South China Block is conducted by Dr. GAO Biao, Prof. CHEN Jitao, Prof. ZHENG Quanfeng, Dr. HUANG Xing, and Ph.D. student XIN Hao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with Dr. HU Keyi from Nanjing University. The study established a high-precision biostratigraphic framework and recovered the sedimentary environment and its evolution based on sedimentary petrographic analysis, and identified an enhanced water cycle event due to climate changes during the Middle-Late Moscovian. The research achievements were published in the international journal Global and Planetary Change. The conodont and fusulinid biostratigraphy indicate that the Outangdi succession formed during the middle to late Moscovian. Twelve facies and five facies associations have been recognized in the Outangdi section, which suggest an overall carbonate ramp environment episodically interrupted by siliciclastic influx of braid delta (Fig. 3). An anomalous siliciclastic deposit (with thickness of ca. 5 m) around the Podolskian substage has been recognized in the Outangdi succession. Such an abrupt siliciclastic influx event has also been recorded in the Madiyi succession in central South China, as well as other sections in the tropical peri-Paleotethys regions in the late Moscovian. This abrupt increase of siliciclastic influx reflects an enhanced water cycle in the paleotropical zone due to climate changes responding to the demise of C4 glacial interval in the late Moscovian (Fig. 4). The research is supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences. Reference: Gao, B., Xin, H., Huang, X., Hu, K.Y., Zheng, Q.F., and Chen, J.T.* (2022), A record of enhanced water cycle in the late Paleozoic icehouse, Global and Planetary Change. 218, 103957. https://doi.org/10.1016/j.gloplacha.2022.103957. Figure 1. Tectonic framework and paleogeographic map of the Cathaysia Block during the late Carboniferous and location of the study area. Figure 2. Detailed sedimentologic logging of the Outangdi section. Figure 3. Depositional model. (A) Lower Outangdi succession (from -15.9 m to -3.8 m). (B) Upper Outangdi succession (from -3.8 m to 34.0 m). Figure 4. Global correlation of stratigraphy and inferred paleoclimate events during the Moscovian. (A) Synthesis of late Moscovian sedimentary and paleoclimate records in the paleotropical zone. (B) Paleogeographic map marked with paleoclimate belts in the late Carboniferous.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China A record of enhanced water cycle in the late Paleozoic icehouse
PtilozamitesNathorst 1878 is a seed fern genus widely documented from the Early Mesozoic with over 140 years long history; but the systematic position of Ptilozamites was debated for decades. Ptilozamites Nathorst 1878 is a seed fern genus widely documented from the Early Mesozoic with over 140 years long history; but the systematic position of Ptilozamites was debated for decades. The investigation of Ptilozamitesin China had started in 1950 due to the first discovery of Ptilozamiteschinensisby Hsü in Hunan Province. However, the systematic affinity of this plant was once transferred to the genus Pseudoctenis because of the preservation of specimens with lack of cuticular structures. Recently, a new report was published in the international journal Review of Palaeobotany and Palynology by a research team led by Prof. WANG Yongdong from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS). The team members include Prof. Mihai E. Popa (University of Bucharest of Romania), Prof. Evelyn Kustatscher (Ludwig Maximulian University of Munich, Germany), Ph.D. student and palaeobotanists from NIGPAS XU Yuanyuan, Dr. ZHANG Xiaoqing, Dr. LU Ning, Dr. LI Liqin, as well as Prof. ZHANG Tingshan’s team from Southwest Petroleum University of China. The well-preserved fossil material belonging to Ptilozamiteschinensis was recently collected from the Upper Triassic Xujiahe Formation in Guangyuan City of northern Sichuan Basin and the Upper Triassic Xiaoping Formation in central Guangdong Province. The detailed morphology and anatomy of these materials were studied and a neotype and an emended diagnosis for Ptilozamiteschinensis were proposed. The pinnule apex of Ptilozamiteschinensis are truncate or tipped with 2–4 mucrones, which is regarded as a kind of intraspecific morphological variability (Figs. 1-2). The stomata are haplocheilic, with obviously sunken guard cells surrounded by 4–7 subsidiary cells (Fig. 3). The systematic investigation of the cuticular and the macro-morphological characters supports the assignment of the species to the genus Ptilozamites rather than to the previous proposal to genus Pseudoctenis. A comparison with the previously documented specimens of Ptilozamiteschinensis suggests a different overall morphology during the developmental process of this plant. The palaeogeographic distribution of Ptilozamiteschinensis indicates a preference for hot and humid habitats during the Late Triassic of the Southern Floristic Province, and can be considered as an important marker for the Rhaetian (Fig. 4). Its short stratigraphic range in the Southern Floristic Province (with no fossil record in the Northern Floristic Province) indicate that this taxon most likely lived in humid and hot environments and its final extinction after the Triassic/Jurassic boundary may represents an ecological response to the regional climate change. This study was co-sponsored by the National Natural Science Foundation of China, Strategic Priority Research Program (B) of the Chinese Academy of Sciences, the State Key Laboratory of Palaeobiology and Stratigraphy and Natural Science Foundation of Jiangsu Province, China. Reference: Yuanyuan Xu, Mihai E. Popa*, Xiaoqing Zhang, Evelyn Kustatscher, Ning Lu, Liqin Li, Jianli Zeng, Tingshan Zhang, Yongdong Wang*, 2022. Ptilozamiteschinensis (Pteridospermopsida) from the Late Triassic of South China with considerations on its intraspecific variability and palaeoenvironmental preferences. Review of Palaeobotany and Palynology, 304: 104727. https://doi.org/10.1016/j.revpalbo.2022.104727. Fig. 1.New material and cuticles of Ptilozamiteschinensis Hsu, 1950 from the Upper Triassic of South China. Fig. 2.Representative material of Ptilozamiteschinensis Hsu, 1950 from the Upper Triassic of South China, showing denticulate and rounded apices of pinnules. Fig. 3.Cuticles of Ptilozamiteschinensis Hsu, 1950 from the Upper Triassic of China, showing details of stomatal apparatus. Fig. 4.Palaeogeographic and geographical distribution of the outcrops yielding Ptilozamiteschinensis during the Late Triassic in China. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
An international research team led by Dr. ZHANG Huaqiao from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has used hundreds of new fossil specimens to clarify the anatomy and evolutionary affinity of Saccorhytus, originally thought to be a deuterostome. An international research team led by Dr. ZHANG Huaqiao from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has used hundreds of new fossil specimens to clarify the anatomy and evolutionary affinity of Saccorhytus, originally thought to be a deuterostome. The study was published in Nature on Aug. 17. Dr. LIU Yunhuan from Chang'an University, Dr. XIAO Shuhai from Virginia Tech, Dr. Philip C. J. Donoghue and Miss Emily Carlisle from the University of Bristol, and Dr. Michael Steiner from Shandong University of Science and Technology were also involved in the study. Saccorhytus, which was originally described in 2017, was discovered from the Cambrian Fortunian Zhangjiagou section of southern Shaanxi Province, China. It was interpreted to be an ancestral deuterostome. It is microscopic in size—about a millimetre in diameter—and resembles a spiky, wrinkly sack. Its mouth is surrounded by radial folds, nodes, and holes that were originally interpreted as pharyngeal openings—a primitive feature of deuterostomes. However, the evidence supporting Saccorhytus being a deuterostome was always very weak. Were those holes around the mouth really pharyngeal openings? To address this question, the research team collected hundreds of new Saccorhytus specimens from the Cambrian Fortunian Zhangjiagou and Shizhonggou sections of southern Shaanxi Province. Many of the specimens were much better preserved than any seen before, thus providing new information about the anatomy and evolutionary affinity of Saccorhytus. Based on these discoveries, the anatomy of Saccorhytus is now clear. Saccorhytus has a millimetric, ellipsoidal body, with one half slightly wider than the other half. Its integument is two-layered and non-ciliated. The mouth is situated terminally, and is surrounded by radial folds, one circlet of circumoral protuberances, and one to five large protuberances on one side of the body; all protuberances have a central main spine flanked by two lateral spines with a closed tip. Four to eight pairs of body cones are bilaterally arranged around the oral-aboral axis, each with an expanded conical base that is ornamented with longitudinal folds and supports an apical spine with a closed tip. Many nodes occur on the same side of the body as the large protuberances. In addition, many small, sharp-tipped spines are positioned on the aboral side of the body. No internal biological structures are preserved and the anus is absent. The team interpreted the integument as cuticle rather than epidermis. This is because cuticle contains multiple sub-layers (i.e., epicuticle, exocuticle, and endocuticle), whereas epidermis contains a single, very thin layer of epithelial cells. Furthermore, cuticle is decay-resistant and has relatively high fossilization potential, whereas epidermis is soft and decays quickly after death. This interpretation is consistent with the abundance of Saccorhytus specimens in the studied rocks, indicating that they have relatively high preservation potential. It is also consistent with experimental taphonomy on ecdysozoans, which shows that ecdysozoan epidermis, muscles, and visceral organs decay very quickly after death, leaving only cuticular structures and intestines. The researchers found that the circumoral/large protuberances, body cones, and small spines are all spinose structures with closed, sharp tips. Since the body cones have no openings, they cannot be interpreted as possible pharyngeal openings. The integument represents cuticle, with no trace of cilia, implying that the underlying epidermis is non-ciliated. The mouth has now been reinterpreted as terminal rather than ventral. Saccorhytus has three body axes. The terminal mouth defines the oral-aboral axis; the distribution of body cones defines the left-right axis; whereas the polarized distribution of nodes and large protuberances defines the third axis. Thus, Saccorhytus belongs to Bilateria and the three body axes represent the anterior-posterior axis, left-right axis, and dorsal-ventral axis, respectively. Saccorhytus is different from any known bilaterians in general morphology and body plan, but the research team have been able to find four key characteristics that help address the affinity of Saccorhytus, including a terminal mouth, the presence of cuticle, non-ciliated epidermis, and the presence of radially arranged circumoral structures. This suite of characteristics generally occurs in ecdysozoans. In particular, radially arranged circumoral structures are common to Cambrian and extant ecdysozoans. In other words, evidence pointed to Saccorhytus being an ecdysozoan. In order to test the ecdysozoan hypothesis, the research team conducted a comprehensive morphology-based phylogenetic analysis along with several experiments to test different possibilities. In all tests, results supported the hypothesis that Saccorhytus belongs to the total-group Ecdysozoa; conversely, the deuterostome and cnidarian hypotheses were not supported. Saccorhytus now represents one of the earliest known ecdysozoans. Although the exact position of Saccorhytus within the total-group Ecdysozoa is unclear, the sac-like body of Saccorhytus challenges the traditional worm-like body of ecdysozoans. It also implies that the ancestor of the ecdysozoans may not be worm-like. All in all, the origin of the ecdysozoan body plan awaits further study of the interrelationships among the earliest known ecdysozoans in the Cambrian Fortunian Age. SEM images of Saccorhytus coronarius Artistic reconstructions and phylogenetic position of Saccorhytus coronarius. A, anterior view; B, left view; C, posterior view; D, Saccorhytus is a total-group ecdysozoan Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Parental care refers to the protection, care and feeding of eggs or offspring by parents, is considered as a significant behavioural adaptation in life-history traits. It has evolved independently multiple times in animals, e.g. mammals, birds, dinosaurs and arthropods, especially various lineages of social insects. Parental care refers to the protection, care and feeding of eggs or offspring by parents, is considered as a significant behavioural adaptation in life-history traits. It has evolved independently multiple times in animals, e.g. mammals, birds, dinosaurs and arthropods, especially various lineages of social insects. Brood care is a form of uniparental care where parents carry eggs or juveniles after oviposition and provide protection, enhancing offspring fitness and survival. However, very few fossil insects directly document such an ephemeral behaviour. Among Mesozoic insects, the only two direct fossil cases of brooding ethology are from the Early Cretaceous Jehol biota and mid-Cretaceous Burmese amber. In recent years, a research group led by Prof. HUANG Diying of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) systematically studied the water boatman Karataviella popovi, a representative insect from the Middle–Late Jurassic Daohugou biota of northeastern China. Of the 157 examined K. popovi fossils, 30 adult females were preserved with a cluster of eggs anchored on their left mesotibia. Various analytical technologies and methods have been used in this study, and a comprehensive analysis of functional morphology revealed the unique egg carrying behaviour of the Jurassic water boatman. The discovery represents the earliest direct evidence of brood care among insects, indicating that relevant adaptations associated with maternal investment of insects can be traced back to at least the Middle Jurassic, pushing back by approximately 40 million years. The relevant results were published online in Proceedings of the Royal Society B on July 13th. The true water bug superfamily Corixoidea, commonly known as the water boatman, is a common aquatic Hemipteran insect, occurs in various freshwater ecosystems worldwide. Extant water boatmen commonly deposit eggs on various subaquatic substances such as leaves or stems of aquatic vegetation, stones, and even on snail shells, carapaces of terrapins, and the exoskeletons of crayfish. The Jurassic water boatman K. popovi from the Daohugou biota bears a relatively large body, with its body length ranging from 11–15 mm. The specialized protarsi of K. popovi, combined with the five patches of setae on the head forming a trawl-like feeding apparatus, reflecting the highly specialized predatory behavior. The anostracan and the water boatman K. popovi represent the precursors and dominators in the same layer of the Daohugou beds, and they show high consistency with their emergence, radiation, prosperity, decline and extinction. After analysis of more than 700 anostracan eggs, we hypothesize that the abundant seasonally produced anostracan eggs in the Daohugou biota probably are the food source of K. popovi. The egg clusters of K. popovi are compact, and arranged in approximately 5–6 staggered rows, attached to and throughout the left mesotibia of adult females by short egg stalks. As inferred from the arrangement of the eggs, each row seems to have 6–7 eggs. The diameters of egg (without stalk) range from 1.14 to 1.20 mm. This study hypothesize that due to the potential high predation risk caused by abundant salamanders in the Daohugou biota and seasonal food resources, K. popovi may have been exposed to fierce ecological pressure in the Daohugou biota. The brooding behaviour developed in K. popovi probably reflected adaptations to habitat or an evolutionary response to the ancient lake ecosystem changes. The brooding behaviour of K. popovi most likely provided effective protection for eggs, largely avoiding the risks of predation, desiccation and hypoxia, which had important effects for its evolution, development and reproductive success. However, this selfless behaviour of K. popovi incurred high ecological costs, which causes an increased risk of predation. To our knowledge, carrying a cluster of eggs on a leg is a unique strategy among insects, but is not unusual in aquatic arthropods, in which this carrying behaviour even can be traced back to the early Cambrian Chengjiang biota. The water boatman K. popovi could be viewed as a plesiomorphic relic. Our discovery highlights the existence of diverse brooding strategies in Mesozoic insects, which are helpful for understanding the evolution and adaptive significance of brood care in insects. This work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the International Postdoctoral Exchange Fellowship Program. FANG Yan and LI Yan-da provided for technical support, and SUN Jie prepared the reconstructive illustration. Figure 1. The morphological characters of Karataviella popovi. Figure 2. Brooding in Karataviella popovi. Figure 3. The specialized filter-capture apparatus in Karataviella popovi. Figure 4. Ecological reconstruction of Karataviella popovi. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Western Sichuan Basin . Scale bar = 20 μ m . Fig . 2 Carnian palynofloral composition revealing paleoclimatic setting in Jiangyou area Fig . 3 Correlation of the carbon-isotope records and palaeoclimate proxies between eastern and western Tethys during the mid-Carnian .H/X ratio : hygrophyte/xerophyte ratio . Contact : LIU Yun , PropagandistEmail : yunliu @ nigpas . ac . cnNanjing Institute of Geology and Palaeontology , Chinese Academy of SciencesNanjing , Jiangsu 210008 , China. The Late Triassic Carnian Stage witnessed major climatic changes during the mid-Carnian (Julian 2-Tuvalian 1), known as the “Carnian Pluvial Episode” (CPE). The CPE is characterized by increased rainfall, humid and warmer climate, oceanic anoxia, carbon cycle perturbations and demise of carbonate platforms. The global extent of the CPE-related humid climate and their impact on the terrestrial ecosystem are the major highlighted issues for the studies. Recently, Dr. LI Liqin, Prof. WANG Yongdong and their group from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), and Prof. Wolfram M. Kürschner from the University of Oslo, investigated the palynoflora from the Ma’antang Formation at Ma’antang section in Jiangyou area, western Sichuan Basin, and reconstructed Carnian paleovegetation and paleoclimatic setting in this area. The research results were recently published in Review of Palaeobotany and Palynology, an international journal. The Ma’antang section in the Jiangyou area is the type section the Ma’antang Formation. The previous ammonite and conodont studies have established a relatively reliable geological age frame work for this formation. Diverse and well-preserved sporomorphs were identified from the Ma'antang Formation at Ma'antang section, and two palynological assemblages were distinguished. The study reveals dominance of fern spores (represented by Dipteridaceae/Matoniaceae) in the Ma’antang palynoflora, especially in the middle part of the Ma’antang Formation. Lycopsid spores and gymnosperm pollen (including conifers, cycadophytes/ginkgophytes and seed ferns) are much less abundant. This palynofloral composition reflects a general humid climate setting in the western Sichuan Basin during the Carnian. Overwhelming predominance of wet Lowland SEG and hygrophyte elements, and increased Lowland/Hinterland as well as hygrophyte/xerophyte ratios observed in Units 2-4 of the Ma’antang Formation, suggesting intensified humidity during the Julian 2 in this area. This study correlates well with observations from North China as well as western Tethys, thus further supports a global nature of humid climate associated with the CPE. This study presents the first palynological evidence for vegetation changes and humid climate during the CPE in South China, providing important evidence for better understanding the terrestrial vegetation response to the CPE 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, and the State Key Laboratory of Palaeobiology and Stratigraphy. Reference: Li, L.Q., Kürschner, K.M., Lu, N., Chen, H.Y., An, P.C., Wang, Y.D.*, 2022. Palynological record of the Carnian Pluvial Episode from the northwestern Sichuan Basin, SW China. Review of Palaeobotany and Palynology, 304: 104704. https://doi.org/10.1016/j.revpalbo.2022.104704.
Fig. 1 Representative fossil spores from the Ma’antang Formation at Jiangyou, western Sichuan Basin. Scale bar= 20 μm.
Fig. 2 Carnian palynofloral composition revealing paleoclimatic setting in Jiangyou area
Fig. 3 Correlation of the carbon-isotope records and palaeoclimate proxies between eastern and western Tethys during the mid-Carnian. H/X ratio: hygrophyte/xerophyte ratio.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Triprojectacites is an extinct fossil pollen group characterized by three projections at the equator, which mainly thrived during the Late Cretaceous. The Northern Hemisphere palynofloras during the Late Cretaceous can be divided into a Normapolles province and an Aquilapollenites province, the latter of which is represented by the existence of Triprojectacites. Triprojectacites is an extinct fossil pollen group characterized by three projections at the equator, which mainly thrived during the Late Cretaceous. The Northern Hemisphere palynofloras during the Late Cretaceous can be divided into a Normapolles province and an Aquilapollenites province, the latter of which is represented by the existence of Triprojectacites. Northeast China constitutes an important part of the Aquilapollenites Provincein yielding abundant fossils of this special pollen group. This pollen group is of great significance in the study of stratigraphic division and correlation of the Upper Cretaceous, palaeoecology and palaeoclimate during that timefor its unique morphology, high diversity, short distribution, and rapid evolution. However, due to the complexity in morphology, it is hard to be correctly observed, described and measured, resultingin a mess of its systematic classification and identification, which then has seriously hindered its scientific applications. Recently, WU, Yixiao, a Ph.D. candidate in Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), with her supervisor, Prof. LI, Jianguo, and others, carried out a detailed research on the morphology, systematics, geological distribution, and evolution of Triprojectacites based on the material froma scientific drilling well, SK-1, in the Songliao Basin. A series of results has been approached and published in international journals Grana and Cretaceous Research. The SK-1 well in the Songliao Basin is ideal for the study of Triprojectacites for its highly detailed research, particularly the high-precision chronological framework. A total of 101 samples have been checked from the well to observe pollen morphology under optical, scanning electron, and transmission electron microscopes using single-grain technology. The morphological features of Triprojectacites have been clarified, including its shape, polarity, aperture, ornamentation and wall structure. A standardized morphological terminology and measuring method have been proposed. Finally, eight genera were screened out from the thirty-nine genera that have been proposed in relation with Triprojectacites. A classification system at generic level of Triprojectacitesis established. The composition and distribution of generaand species of Triprojectacites was investigated through the SK-1 well, exhibiting a five-phase evolution of Triprojectacites in the Songliao Basin as occurrence, radiation, steady development, climax, and extinction. During its evolution, Triprojectacites tend to be larger in size, more robust and complicated in ornamentation, and bearingaccessory structures. These research advances have laid a solid foundation for the research andapplication of Triprojectacites in species classification and evolution, and will promote its use in the study of global division and correlationof terrestrial Cretaceous strata, palaeoecology, and palaeogeography as well. These studies were jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Rereference: Wu, Y., Li, J., 2022. Genus classification of Triprojectacites Mtchedlishvili, 1961 emend. Stanley 1970. Grana, 61(3): 161–181. https://doi.org/10.1080/00173134.2022.2050804. Wu, Y., Li, J., Lin, M., & Koppelhus, E., 2022. Triprojectacites in the Songliao Basin, Northeast China: Systematics, biostratigraphy and evolution. Cretaceous Research, 135: 105193. https://doi.org/10.1016/j.cretres.2022.105193. Figure 1 SEM, TEM images of major ornamentationtypes in Triprojectacites Figure 2 Genera and species diversity of Triprojectacites in the Songliao Basin Figure 3 Evolution of each genera and species of Triprojectacites in the Songliao Basin
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The reconstructed complex ecosystem based on the present Liexi fauna provides new evidence for the significant biotic turnover from Cambrian to the Palaeozoic evolutionary faunas, by showing a mixture of Cambrian relics, and the Ordovician new arrivals. In the 1980s, the famous palaeontologist Prof. Sepkoski proposed the diversity curve of the marine animal, recognized three evolutionary faunas, and proposed the concept of Ordovician radiation. From the beginning of the Ordovician, marine life started its great radiation, as manifested by the rapid appearance of new orders, families, and genera, together with the replacement of existing groups. The Great Ordovician Biodiversification Event (GOBE) constructed the essential framework of the Palaeozoic Evolutionary Fauna, while the Cambrian faunas dominated by the arthropods were replaced by the Palaeozoic faunas represented by the filter feeders and reef-forming organisms. GOBE was primitively studied and defined with the skeletonized taxa, rather than the non-mineralized taxa. The exceptionally preserved Lagerstatten have been assessed as reflecting the living community, providing new evidence to know the Ordovician marine world. However, only several Ordovician Lagerst？tten have been discovered before, especially in the Early Ordovician. Recently, a new Lagerstatte, Liexi fauna, was reported by the research team from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Hunan Museum and Central South University, from the Lower Ordovician of Yongshun country, Hunan Province. This work has been published online in Proceedings of the Royal Society B. The Liexi fauna has been discovered from the Madaoyu Formation of Lower Ordovician near the Liexi village, Yongshun county, Hunan Province. The conodont and graptolite assemblages indicate an age of mid-Florian, Early Ordovician, which is slightly younger than the Fezouata biota from Morocco and the Afon Gam biota from Welsh. Most of the documented fossiliferous Early Ordovician Lagerstatten globally are interpreted to occur in high latitude regions, such as the Fezouata biota near the South Pole, and the Afon Gam biota from North Wales at a palaeolatitude of 60°S. During the Early Ordovician, South China was thought to be a typical tropical palaeogeographical setting. In contrast to some other Ordovician Lagerstatten preserved in restricted or anoxic environments, the depositional environment of the Liexi fauna is interpreted to be offshore to the lower shoreface, following the palaeogeographic setting. The Liexi fauna includes up to 11 phyla of marine animals. The fauna is characterized by abundant, diverse biomineralized fossils along with the exceptional preservation of some non-mineralized tissues and groups. In addition to rich palaeoscolecidans and diverse trilobites (including the digestive tract preservation), the fauna also contains graptolites, extraordinarily complete echinoderms, exceptionally-preserved sponges, possible Ottoia, machaeridian polychaetes, and other rare biomineralized specimens, signalling a flourishing Early Ordovician marine fauna. A biologically complex and complete marine ecosystem with diverse organisms and varied lifestyles is proposed here, including endobenthic, sessile benthic, mobile benthic, nektonic, and planktic taxa. Any discoveries of Early Ordovician Lagerstatten are of significant concern for the research on the Cambrian to Ordovician faunal transition. The Liexi fauna is suggested as the age of middle Floian, probably preceding the GOBE’s primary interval of diversification by ~5–10 Myr. The reconstructed complex ecosystem based on the present Liexi fauna provides new evidence for the significant biotic turnover from Cambrian to the Palaeozoic evolutionary faunas, by showing a mixture of Cambrian relics, and the Ordovician new arrivals. This research is supported by CAS Strategic Priority Research Program (B) and National Nature Science Foundation of China. Reference: Fang, X., Mao, Y.Y., Liu, Q., Yuan, W.W., Chen, Z.Y., Wu, R.C., Li, L.X., Zhang, Y.C., Ma, J.Y., Wang, W.H., Zhan, R.B., Peng, S.C., Zhang, Y.D., Huang, D.Y.*, 2022. The Liexi fauna: a new Lagerstatte from the Lower Ordovician of South China. Proceedings of the Royal Society B, 289: 20221027. https://doi.org/10.1098/rspb.2022.1027.
Fossils from the Liexi fauna
Palaeoscolecidan worms from the Liexi fauna
Ecological reconstruction of the Liexi fauna (Drawn by J. Sun)
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The so-called Triassic-Jurassic Extinction(~202millionyearsago) killed off the big reptiles that up until then had ruled the planet, thus clearing the way for dinosaurs to take over. But why did dinosaurs thrive when other creatures died? The so-called Triassic-Jurassic Extinction(~202millionyearsago) killed off the big reptiles that up until then had ruled the planet, thus clearing the way for dinosaurs to take over. But why did dinosaurs thrive when other creatures died? Now a new study led by researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and Columbia University answers this question. It reveals that Triassic dinosaur species—then a minor group largely relegated to the higher latitudes—regularly endured freezing conditions, suggesting they were well-adapted to the cold in a way that non dinosaurian species were not. Thus, when the Central Atlantic Magmatic Province (CAMP) caused years to decades of global volcanic winter at the end of the Triassic, dinosaurs were able to survive while then-dominant reptiles could not. The study was published in Science Advances on July 2. The researchers’ conclusion relied on two key findings: First, the researchers found physical evidence of dinosaur footprints from the Junggar Basin in Xinjiang Uygur Autonomous Region of northwestern China. During the Late Triassic to Early Jurassic, this region was located at about 71 degrees north, well above the Arctic Circle. The footprints showed that dinosaurs were present along shorelines. Second, when the researchers analyzed deep lake deposits, they found abundant pebbles up to about 1.5 centimeters in diameter within normally fine sediments. Far from any apparent shoreline, the pebbles had no business being there. That left only one plausible explanation: They were ice-rafted debris (IRD). Finding evidence of IRD was crucial to the study because it provided important climate clues. IRD is created when ice abuts a coastal landmass and incorporates bits of underlying rock as it freezes. At some point the ice becomes unmoored and drifts into the adjoining water body. When it melts, the rocks drop to the bottom, mixing with normally fine sediments. Geologists have extensively studied ancient IRD in the oceans, where it is deposited by glacial icebergs, but rarely in lake beds; the Junggar Basin discovery adds to the scant record. The researchers said the pebbles were likely picked up during winter, when lake waters froze along pebbly shorelines. When warm weather returned, chunks of ice floated away with pebbles in tow and later dropped them. “This shows that these areas froze regularly and the dinosaurs did just fine,” said study co-author Dennis Kent, a geologist at Columbia University’s Lamont-Doherty Earth Observatory. The researchers then used phylogenetic bracket analysis to conclude that the dinosaurs were primitively insulated with feathers. This insulation allowed them to adapt to intense volcanic winters and cold polar conditions so they could take advantage of the Arctic’s deciduous and evergreen vegetation. “The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it got cold everywhere, they were ready, and other animals weren't,” said Paul Olsen from Columbia University. While the end of the Triassic is often associated with deadly temperature spikes due to high carbon dioxide concentrations from volcanic eruptions, those same eruptions also deflected a great deal of sunlight, leading to volcanic winters. “Severe wintery episodes during volcanic eruptions may have brought freezing temperatures to the tropics, which is where many of the extinctions of big, naked, unfeathered vertebrates seem to have occurred,” said SHA Jingeng from NIGPAS. “Where as our fine feathered friends acclimated to colder temperatures in higher latitudes did okay.” After the biological extinction event at the end of the Triassic, dinosaurs rapidly increased in size and expanded their geographic range, with the total number of dinosaurs nearly doubling. From then on dinosaurs started their135-million-year-long terrestrial domination of Earth. Fig. 1 The supercontinent of Pangaea 202 million years ago, shortly before the Triassic-Jurassic Extinction. (Image by Olsen et al.)
Fig. 2 A shale cliff in the Junggar Basin in northwestern China, where scientists found ice-rafted pebbles amid otherwise fine-grained sediments. (Image by Paul Olsen)
Story Source: Materials provided by Columbia Climate School. Original written by Kevin Krajick. Note: Content may be edited for style and length. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
A research team has now conducted a study of yunnanozoans, extinct creatures from the early Cambrian period (518 million years ago), and discovered evidence that they are the oldest known stem vertebrates. The term stem vertebrate refers to those vertebrates that are extinct, but very closely related to living vertebrates. Scientists have long puzzled over the gap in the fossil record that would explain the evolution of invertebrates to vertebrates. Vertebrates, including fishes, amphibians, reptiles, birds, mammals, and humans, share unique features, such as a backbone and a skull. Invertebrates are animals without backbones. The process that moved invertebrates toward becoming vertebrates — and what those earliest vertebrates looked like — has been a mystery to scientists for centuries. A research team has now conducted a study of yunnanozoans, extinct creatures from the early Cambrian period (518 million years ago), and discovered evidence that they are the oldest known stem vertebrates. The term stem vertebrate refers to those vertebrates that are extinct, but very closely related to living vertebrates. The research team, from Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, and the Nanjing University, published their findings in the journal Science on July 8, 2022. Across the years, as scientists have studied how vertebrates evolved, a key focus of research has been the pharyngeal arches, those structures that produce parts of the face and neck, such as the muscles, bone, and connective tissue. Researchers have hypothesized that the pharyngeal arch evolved from an unjointed cartilage rod in vertebrate ancestors, such as the chordate amphioxus, a close invertebrate relative of the vertebrates. But whether such anatomy actually existed in the ancient ancestors has not been known for certain. In an effort to better understand the role of the pharyngeal arch in ancient vertebrates, the research team studied the fossils of the soft-bodied yunnanozoans found in the Yunnan Province, China. For years, researchers have studied the yunnanozoans, with differing conclusions on how to interpret the creature’s anatomy. The affinity of yunnanozoans has been debated for around three decades, with multiple papers published supporting varying opinions, including four in Nature and Science. The research team set out to examine newly collected yunnanozoan fossil specimens in previously unexplored ways, conducting a high-resolution anatomical and ultrastructural study. The 127 specimens they studied have well-preserved carbonaceous residues that allowed the team to conduct ultrastructural observations and detailed geochemical analyses. The team applied X-ray microtomography, scanning electron microscopy, transmission electron microscopy, Raman spectrometry, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy on the fossil specimens. Their study confirmed in multiple ways that yunnanozoans have cellular cartilages in the pharynx, a feature considered specific to vertebrates. The team’s findings support that yunnanozoans are stem vertebrates. The results of their study show that the yunnanozoans are the earliest and also the most primitive relatives of crown-group vertebrates. During their study, the team observed that all of the seven pharyngeal arches in the yunnanozoan fossils are similar to each other. The all arches have bamboo-like segments and filaments. Neighboring arches are all connected by dorsal and ventral horizontal rods, forming a basket. A basket-like pharyngeal skeleton is a feature found today in living jawless fishes, such as lampreys and hagfishes. "Two types of pharyngeal skeletons—the basket-like and isolated types—occur in the Cambrian and living vertebrates. This implies that the form of pharyngeal skeletons has a more complex early evolutionary history than previously thought," said Qingyi Tian, the first author of the study, from Nanjing University and Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences. Their research provided the team with new insights into the detailed structures of the pharyngeal arches. The new anatomical observations the team achieved in their study, support the evolutionary placement of yunnanozoans at the very basal part of the vertebrate tree of life. The research team includes Qingyi Tian from Nanjing University (NJU) and Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS); Fangchen Zhao and Han Zeng from NIGPAS; Maoyan Zhu from NIGPAS and the University of Chinese Academy of Sciences; and Baoyu Jiang from NJU. The Strategic Priority Research Program (B) of the Chinese Academy of Sciences and the National Science Foundation of China funded this research. Reference: Qingyi Tian, Fangchen Zhao*, Han Zeng, Maoyan Zhu, Baoyu Jiang*, 2022. Ultrastructure reveals ancestral vertebrate pharyngeal skeleton in yunnanozoans. Science, 377(6602), https://www.science.org/doi/10.1126/science.abm2708.
Caption: Artistic reconstruction of the yunnanozoan from the Cambrian Chengjiang biota shows basket-like pharyngeal skeletons (Drawn by Dinghua Yang). Credit: Fangchen Zhao, NIGPAS
Caption: The stem vertebrate yunnanozoan. Credit: Fangchen Zhao, NIGPAS
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
