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
Abundant rudist bivalves have been reported from the Yigeziya Formation, most of them were considered as endemic taxa that were restricted to central Asia including Tajik, Fergana, Alai and Tarim basins. During Cretaceous to Paleogene, a shallow epicontinental sea extended across Eurasia from the Mediterranean Tethys to the southwestern Tarim Basin, and its eastern extremity being referred to as the Tarim Sea, which was commonly regarded as a branch of the Neotethys. During Late Cretaceous, two distinct transgressive events have been identified in Tarim Sea: the first is represented by the deposition of early Cenomanian to Turonian Kukebai Formation, and the second formed the Campanian to early Maastrichtian Yigeziya Formation. Abundant rudist bivalves have been reported from the Yigeziya Formation, most of them were considered as endemic taxa that were restricted to central Asia including Tajik, Fergana, Alai and Tarim basins. Biradiolites minor Pojarkova, described by Lan and Wei (1995) from the middle member of the Yigeziya Formation, is characterized by the glabrous outer shell layer except for four salient ridges on the shell margin of the right valve. This feature is inconsistent with the genus Biradiolites d’Orbigny which is normally ornamented with strongly protruding longitudinal ridges over the whole right valve. Recently, Dr. RAO Xin from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and her colleagues re-studied the species B. minor based on the published and new specimens, transferred it to the genus Glabrobournonia according to the taxonomic re-examination. Glabrobournonia is a genus of radiolitids characterized by indented radial bands, salient ridges on the shell margins and absence of fine ribs on the surface of the right valve. Apart from southwestern Tarim Basin, Glabrobournonia minor (Pojarkova) has also been recorded from the late Campanian of Fergana and Alai basins. The central Asian, late Campanian to early Maastrichtian G. minor differs from the late Campanian to Maastrichtian, eastern Arabian type species Glabrobournonia arabica Morris and Skelton in the flat left valve and an additional fourth ridge on the junction of the dorsal and posterior sides of the right valve. Biradiolites ingens (Des Moulins) could be the direct ancestor of Glabrobournonia. The paleogeographic distribution of Glabrobournonia suggests that this genus dispersed to central Asia from the late Campanian time, becoming widely distributed in the eastern Tethyan region rather than endemic to eastern Arabia. Correspondingly, specimens belonging to Gyropleura yielded from the same bed as G. minor in southwestern Tarim Basin, are similar to the specimens which were attributed to the eastern Arabian Gyropleura sp.; Campanian to early Maastrichtian Osculigera specimens described from the Yigeziya Formation are comparable with those known from the Campanian–Maastrichtian of Iran, Afghanistan and eastern Arabia. The similarity of the rudist assemblages between central Asia and eastern Arabia suggests a faunal connection and affinity between the north and south margins of the eastern Tethyan realm during Campanian to early Maastrichtian times. This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the Second Tibetan Plateau Scientific Expedition and Research, the National Natural Science Foundation of China, and the State Key Laboratory of Palaeobiology and Stratigraphy, Chinese Academy of Sciences. Reference: X. Rao, P. W. Skelton, S. Sano et al., Taxonomy and paleobiogeographic implication of Glabrobournonia Morris and Skelton (Hippuritida, Radiolitidae) from the Late Cretaceous Yigeziya Formation, southwestern Tarim Basin, Palaeoworld, https://doi.org/10.1016/j.palwor.2022.05.003. Fig. 1. (a) Map of the southwestern Tarim Basin and adjacent basins bearing Late Cretaceous rudists. (b) Geologic map showing the fossil locality in southwestern Tarim Basin. (c) Stratigraphic column of the Yigeziya section and the occurrence of Glabrobournonia minor within the section. Fig. 2. Glabrobournonia minor (Pojarkova) from the Yigeziya Formation of the Yingjisha County, southwestern Tarim Basin. Scale bar represents 10 mm. Fig. 3. Paleogeographic map of late Campanian showing the reconstructed situations of the fossil localities bearing Glabrobournonia (base map after Scotese, 2014). Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Resource pulses, occasional events of ephemeral resource superabundance, represent a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. They are widespread in extant ecosystems; however, little is known about their deep-time record. Resource pulses, occasional events of ephemeral resource superabundance, represent a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. They are widespread in extant ecosystems; however, little is known about their deep-time record. Recently, ZHANG Qianqi, a PhD student from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the supervision of Profs. WANG Bo and ZHANG Haichun, in collaboration with other researchers carried out a detailed investigation of early Mesozoic terrestrial strata in several regions in southern China. The researchers discovered abundant marine and terrestrial animal and plant fossils in the Lower Jurassic Shiti Formation in the Xiwan Basin of Hezhou City, Guangxi Province, China. Researchers report the earliest-known mayfly swarm from the Early Jurassic Xiwan biota of southern China, and the results were published in the journals Geology and Historical Biology. The Mesozoic study in the Xiwan Basin has a long history, and both Profs. SZE Hsing-Chien and ZHOU Zhiyan had ever studied the plant fossils from Xiwan, among which plenty of insect fossils from the Shitian Formation were reported by Prof. LIN Qibin. "We recently found abundant new insects, plants, and shark egg capsules from a new fossil locality. In view of the abundance of the diverse insects and plants, we propose that the fossil assemblage in the lower unit of the Shiti Formation be named the Xiwan biota, which is among the richest Jurassic biotas in China", ZHANG Qianqi says. This research team found one fossil layer with hundreds of mayflies in the lower unit of the Shiti Formation. These mayflies were classified as a new taxon, Jurassephemera zhangi Zhang et al. (2022), which is assigned to the extinct family Sharephemeridae, a stem group mayflies in terms of taxonomic position. This is the first discovery of the mayfly family in China, and is the best preserved fossil of the family. "We measured the orientations of 381 mayflies and found that these mayflies do not show any obvious directionality, although the rose diagram suggests a south westerly trend perhaps reflecting the effect of a slight movement of the bottom water after accumulation of the carcasses", says ZHANG. Furthermore, all the mayflies are complete with body, appendages, and wings attached, which, when taken with the above, indicates that the mayflies were not transported any significant distance in the water after death and were buried in a low-energy preservational environment. Extant mayflies spend most of their life in the aquatic environment as nymphs, and the adults commonly live from as little as 1–2 hours to a few days. During their short adult phase, the males form dense aggregations, and the females must find mating partners while flying in and through large swarms, wherein they copulate and ultimately locate a suitable place to deposit eggs. Mating-swarm behavior was previously known only in crown mayflies; however, our find reveals that such complex behaviors were already well established in stem-group mayflies by the Early Jurassic. "And this finding represents the earliest evidence of mating-swarm behavior in insects", ZHANG says. Using elemental energy spectroscopy and Raman component analysis, the results show that the outermost layer of the fossils of the Xiwan biota is mainly iron oxides and clay mineral residues, but the surface composition of the fossils is still dominated by carbon elements. The researchers conclude that the iron oxide covering of the fossil surface was formed during the diagenetic process later and likely formed during the weathering process. Aquatic insects play an important role in aquatic food webs, acting as consumers of aquatic plants and animals, and they are in turn consumed by fish and other predators. But aquatic insects can also be important parts of food webs on land when they emerge as adults from the water and fly to disperse and find mates. In addition to providing food bonanzas for predators, emerging insects can also have a fertilizing effect on plant communities next to lakes and streams when they die and decompose. This study shows that some Jurassic mayflies emerged all at once in large swarms, which is a “pulse” of insects moving from the water to land, probably resulting in massive ecosystem fluxes in waterside habitats with impacts on basic ecology and biogeochemical cycling. Such a mechanism that can play a substantial role in nutrient transport from aquatic ecosystems to surrounding terrestrial ecosystems, while this aquatic-terrestrial ecosystem linkage may be a key novelty in Mesozoic lacustrine ecosystems. "Therefore, our finding highlights the underappreciated ecological significance of insects in short-lived feeding bonanzas and mass mortalities in deep-time lacustrine ecosystems." ZHANG added. This research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Zhang Qianqi, Wang Bo*, Zheng Daran, Li Jiahao, Wang Xueheng, Jarzembowski E.A., Xu Chunpeng, Li Ting, Zhang Haichun, Engel M.S. 2022. Mayflies as resource pulses in Jurassic lacustrine ecosystems. Geology. https://doi.org/10.1130/G50055.1. Zhang Qianqi*, Zheng Daran, Jarzembowski E.A., Wang Xueheng, Li Jiahao, Engel M.S. 2022. The first Sharephemeridae (Insecta: Ephemeroptera) from the Jurassic Shiti Formation of South China. Historical Biology. https://doi.org/10.1080/08912963.2022.2077649. Figure 1: Three pieces of fossil surface with mayfly swarms from the Shiti Formation in southern China. All are the same scale and orientation. Figure 2: Sedimentology (A–D) and taphonomy (E–L) of the fossil-bearing layer from the Shiti Formation in southern China. Figure 3: Reconstruction of the Early Jurassic ecosystem of the Xiwan Basin (designed by YANG Dinghua, NIGPAS).
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
What would happen in the near future with continued global warming? What environmental conditions would the life on Earth most likely confront? The episodes of climate changes in the Earth’s deep past, similar to the current global warming, may provide valuable clues to these questions. What would happen in the near future with continued global warming? What environmental conditions would the life on Earth most likely confront? The episodes of climate changes in the Earth’s deep past, similar to the current global warming, may provide valuable clues to these questions. A recent study led by scientists from China, U.S., and New Zealand reveals that an abrupt warming linked to massive carbon emission during an icehouse climate state caused approximately 20% of anoxic areal extent of the seafloor, and significant biodiversity drop. The finding was published by the Proceedings of the National Academy of Sciences of the United States of America on May 2, 2022. As is known, we are currently living under the Cenozoic icehouse climate that has started since 34 Myr ago. However, global temperature rises rapidly under this icehouse over a couple of centuries, in tandem with accelerated ablation of polar glaciers, rising sea-level, and aggravating marine de-oxygenation, and undoubtedly leading to a significant drop in biodiversity. Where would the global warming lead us to in the future? There are substantial uncertainties regarding the modeling results based on current observations, which drive the current focus on understanding past episodes of carbon emission and ocean deoxygenation, particularly under an icehouse climate state. The Late Paleozoic Ice Age (LPIA, between 360 and 280 million years ago) is the longest-lived and the only icehouse that recorded the transition from icehouse to greenhouse climate states since the occurrence of advanced plants and terrestrial ecosystem. The LPIA is also the only geological period that is featured by low atmospheric CO2 and high O2 concentrations, highly comparable to those of the modern day. It is, therefore, critical to study carbon emissions and their consequences during the LPIA for better understanding the processes and feedbacks of the icehouse Earth system, and thus for more precisely predicting the future environmental and biodiversity changes. A international research team led by Dr. CHEN Jitao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Dr. WANG Xiangdong from the Nanjing University, and Dr. Isabel P. Montanez from the University of California, Davis studied the Carboniferous strata from the southern China for over 10 years, with respect to sedimentology, stratigraphy, paleontology, and geochemistry. The Naqing and Narao sections from the Luodian region, Guizhou Province crop out continuous Carboniferous carbonate successions that register geochemical signal of sea water. Scientists collected samples by every 20 cm for over 40-m-thick strata from the two sections and carried out carbon and uranium isotopes to explore the global carbon cycling and marine anoxia. "We utilized global carbon cycle model (LOSCAR) and paleo carbon dioxide concentrations to simulate a total amount of 9,000 Gt C emitted over 300 kyr, causing an increase in sea-surface temperature by ~4℃", CHEN says. "We also modelled an increase in areal extent of the anoxic seafloor from 4% to 22%, causing a dramatic decrease in biodiversity" CHEN Added, "and finally, we performed climate model simulations using the fully coupled Community Earth System model (CESM) to explore the potential mechanisms for the marine anoxia, which are linked to enhanced thermocline stratification and increased nutrient fluxes during the warming." The study further finds that warming-induced marine anoxia may be more pronounced in a glaciated than in an unglaciated period. Reference: Chen, J.T., Montanez, I.P., Zhang, S., Isson, T.T., Macarewich, S.I., Planavsky, N.J., Zhang, F., Rauzi, S., Daviau, K., Yao, L., Qi, Y.P., Wang, Y., Fan, J.X., Poulsen, C.J. Anbar, A.D., Shen, S.Z., Wang, X.D., 2022. Marine anoxia linked to abrupt global warming during Earth’s penultimate icehouse, PNAS, https://doi.org/10.1073/pnas.2115231119. Fig. 1. An abrupt global warming occurred at ~304 Ma under the Carboniferous icehouse climate state, consistent with doubling of atmospheric carbon dioxide, significant negative excursion in carbon isotopes, sea-surface temperature increase, and drop in biodiversity. Fig. 2. Carbon and uranium isotopes recorded in the Naqing section, Guizhou Province, southern China, showing remarkable negative excursions across the Kasimovian-Gzhelian boundary. Modeling results suggest a distinct perturbation in global carbon cycle and an increase in marine anoxia. Fig. 3. Comparison between the KGB warming event during the late Carboniferous icehouse and greenhouse C-perturbation events over the last 300 Myr, indicating that the KGB warming had a more extreme impact on the marine redox landscape relative to its rate of C injection and SST increase than the other events. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Assembly of Gondwana commenced in the Neoproterozoic with final disassembly of the supercontinent completed by the Cretaceous. The configuration of major continental blocks (e.g., India, Australia, East Antarctica, and Africa) of Gondwana has been well reconstructed. However, paleopositions of some small continental fragments along the periphery of Gondwana are still in controversy. Assembly of Gondwana commenced in the Neoproterozoic with final disassembly of the supercontinent completed by the Cretaceous. The configuration of major continental blocks (e.g., India, Australia, East Antarctica, and Africa) of Gondwana has been well reconstructed. However, paleopositions of some small continental fragments along the periphery of Gondwana are still in controversy. The Baoshan, Tengchong, Lhasa, South Qiangtang, and Sibumasu terranes were located along the northern margin of Gondwana before late Early Permian rifting. A substantial amount of work has been carried out, aiming at reconstructing the paleopositions of these terranes from various disciplines such as sedimentary provenance, paleomagnetism, and paleobiogeography. These studies led to various paleogeographic models of northeastern Gondwana. Recently, a paleogeographic study based on detrital zircon U-Pb ages and Hf isotopic values from Paleozoic strata of northeastern Gondwana, which is conducted by GAO Biao, his advisor Prof. CHEN Jitao, and Prof. QIE Wenkun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with the scientist Prof. WANG Xiangdong from Nanjing University. Primary component analysis (PCA) was used to visualize the relative relationship between these terranes and East Gondwana, in addition with the glacier distribution pattern on northeastern Gondwana in the late Paleozoic. The research achievements were published in the international journal Sedimentary Geology. Based on a total of 8209 detrital zircon U-Pb ages and 1606 zircon Hf isotopic values from Paleozoic strata of northeastern Gondwana, a new paleogeographic model has been reconstructed. It indicates that the South Qiangtang, Baoshan, and part of Sibumasu were outboard of the northern margin of Indian Gondwana during the Paleozoic, whereas the Lhasa and Sumatra terranes were located along the northern margin of Australia. Based on provenance shifts of late Paleozoic glaciogenic sedimentary rocks in northeastern Gondwana, two main ice sheets are hypothesized to have developed during the late Paleozoic. This study further confirms the model of a multicenter glacier distribution pattern on Gondwana during the late Paleozoic ice age from a perspective of provenance. The research is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Second Tibetan Plateau Scientific Expedition and Researh Program. This is a contribution to IGCP 700 and DDE (Deep-time Digital Earth) projects. Reference: Gao, B.*, Chen, J.T.*, Qie, W.K., Wang, X.D., 2022. Revisiting the paleogeographic framework of northeastern Gondwana in the late Paleozoic: implications from detrital zircon analysis. Sedimentary Geology. Available online 11 April 2022. https://doi.org/10.1016/j.sedgeo.2022.106144. Schematic geological map of Southeast Asia and detrital zircon samples locations Primary component analysis (PCA) of detrital zircon characteristic age population
Reconstruction of northeastern Gondwana with regional ice centers during the late Paleozoic ice age Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The rapid appearance of major animal groups and complex marine communities during the Cambrian explosion is recorded in large part in Burgess Shale-type lagerst？tten. Nevertheless, most of the well-known Cambrian lagerst？tten are restricted to a few terranes, with most of them occurring in South China (Epoch 2) or Laurentia (Miaolingian). The large tempo-spatial discrepancy of distribution of the soft-bodied fossil lagerst？tten limits our understanding of the Cambrian explosion of animals on earth. The rapid appearance of major animal groups and complex marine communities during the Cambrian explosion is recorded in large part in Burgess Shale-type lagerstatten. Nevertheless, most of the well-known Cambrian lagerstatten are restricted to a few terranes, with most of them occurring in South China (Epoch 2) or Laurentia (Miaolingian). The large tempo-spatial discrepancy of distribution of the soft-bodied fossil lagerstatten limits our understanding of the Cambrian explosion of animals on earth. Named the Linyi Lagerstatte (ca. 504 mya), a new middle Cambrian lagerstatte from the Zhangxia Formation in Shandong Province, North China, provides a new window into the morphological disparity, community structure, and paleogeographic distribution of marine faunas following the Cambrian explosion. A research team from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) reports online April 5 in National Science Review. The limited known spatial distribution of Cambrian lagerstatten thus underscores the importance of the newly discovered Miaolingian Linyi Lagerstatte. The new assemblage contains a variety of well-preserved soft-bodied fossils, among which the non-trilobite arthropods, particularly the mollisoniids and radiodonts, are the most important groups. The Linyi Lagerstatte is remarkable for its excellent preservation of arthropod limbs, eyes, and guts, these well-preserved fossils promise to yield new anatomical data bearing on the early evolution of animals. "The close similarity in taxonomy between the Linyi Lagerstatte of North China and those of Laurentian lagerstatten suggests that North China may have provided a biogeographic link between East Gondwana and Laurentia" Prof. ZHAO Fangchen says. North China is now an important region for investigating the early evolution of middle Cambrian animals, and its Miaolingian deposits have great potential for yielding additional exceptional biotas. Since the discovery of the Chengjiang biota in 1984, South China has gradually become the principal area for the study of early Cambrian Lagerstatte. The discovery of the Linyi Lagerstatte may also open a new chapter in the study of middle Cambrian BST deposits in North China. Reference: Sun, Z.X., Zhao, F.C.*, Zeng, H., Luo, C., Van Iten, H., Zhu, M.Y., 2022. The middle Cambrian Linyi Lagerstatte from the North China Craton: a new window on the Cambrian evolutionary fauna. National Science Review, https://doi.org/10.1093/nsr/nwac069. Fig. 1. Spatial and temporal distribution and taxonomic diversity of 16 major Cambrian lagerst？tten, and the position of the Linyi Lagerstatte Fig. 2. Representative fossils from the Linyi Lagerstatte. A. Thelxiope spinosa; B. Mollisonia symmetrica; C. Monospecific cluster of the sponge Diagoniella sp; D. Thelxiope tangi sp. nov; E, Oral cone of ; Cordaticaris striatus F, Changqingia puteata; G, Worm-like animal; H, Frontal appendages of Cordaticaris striatus; I. Frontal appendage of an amplectobeluid Fig. 3. Biogeographic comparisons of Cambrian lagerstatten and the position of the Linyi Lagerstatte. (A) Ordination plot of non-metric multidimensional scaling (nMDS) analysis. (B) Cluster analysis. (C) Bipartite network analysis Fig. 4. Life on the platform margin of the Miaolingian sea, North China. Based on data from the Linyi Lagerstatte. Drawing by Dinghua Yang Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Insects are today the most diverse group of organisms on Earth and are responsible for a wide array of ecosystem services. They are important components in modern terrestrial ecosystems, and commonly influence ecosystem cycling of carbon and nutrients by modulating the quality and quantity of resources. Understanding the evolution of insects and their roles in deep-time terrestrial ecosystems are key to decoding the rise of modern terrestrial ecosystems. Insects are today the most diverse group of organisms on Earth and are responsible for a wide array of ecosystem services. They are important components in modern terrestrial ecosystems, and commonly influence ecosystem cycling of carbon and nutrients by modulating the quality and quantity of resources. Understanding the evolution of insects and their roles in deep-time terrestrial ecosystems are key to decoding the rise of modern terrestrial ecosystems. Recently, Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), synthesized the fossil record of Mesozoic holometabolous insects and explored fossil evidence for the evolution of key ecological interactions in terrestrial environments. This study was published in Trends in Ecology & Evolution on March 11, 2022. The Mesozoic is a key era for the rise of the modern insect fauna. Among the most important evolutionary events in Mesozoic insects are the radiation of holometabolous insects, the origin of eusocial and parasitoid insects, diversification of pollinating insects, and development of advanced mimicry and camouflage. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecospaces. During the past two decades, there has been enormous progress in our understanding of these events due to the discovery of new fossils and lagerst？tten, which also provide robust evidence for insect-plant and insect-insect ecological interactions. The fossil record of insects contains larger geographic, temporal and taxonomic gaps than the fossil record of vertebrates and of some marine invertebrates. In fact, more than half of all described insect occurrences in the fossil record come from major Lagerst？tten. Due to the depauperate and uneven fossil record, the estimates of insect paleodiversity is mainly restricted to higher-level taxa and the detailed ecological response of insects to several key environmental events is still unclear. Furthermore, there is a preservational bias toward medium-size insects for compression–impression fossil deposits. Although amber can preserve minute insects, before the widespread occurrence of amber with insect inclusions, the fossils mainly showed the patterns of diversity of medium-size insects. This reminds us that the currently-known evolutionary history of some insect interactions may be incomplete. Recent work on the paleobiology, phylogenetics, taphonomy, and other related fields has facilitated novel understanding of important evolutionary events in Mesozoic entomology and opened up new perspectives. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecological niches entailing closer associations with various plants and animals. Mesozoic insects no doubt played a key ecological role in reconstructing and maintaining terrestrial ecosystems. Nonetheless, the potential ecological roles of these insects are not yet fully explored and their importance warrants more detailed paleoecological study. Many extant terrestrial insects are undergoing dramatic declines in abundance and diversity largely due to anthropogenic deforestation and global warming. Although the phylogenetic landscape was distinctly different in the geological past from that of the present day, a greater understanding of the history of insects could make it possible to formulate broader ecological predictions and policies for the future. "We need to understand particularly their pioneering ecological roles in deep-time terrestrial ecosystems and their response to extreme environmental events." Prof. WANG says, "in particular, paleobiological research provides empirical evidence of how insect communities were shaped by natural climatic events of the past, especially global warming in the Mesozoic." Examining changes in taxonomic diversity, morphological disparity, and ecological shift of insects in concert can provide a more comprehensive view of the evolutionary trajectory and could illuminate underlying evolutionary processes without resort to ‘just-so’ stories. Such studies as discussed above may help to mitigate future changes in insect diversity and abundance faced with accelerating global environmental change. 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: Wang Bo, Xu Chunpeng, Jarzembowski E.A. (2022) Ecological radiations of insects in the Mesozoic. Trends in Ecology & Evolution, https://doi.org/10.1016/j.tree.2022.02.007.
Figure 1. The origins of some key insects and plants according to fossil evidence.
Figure 2. Geological range of insect mimesis, debris-carrying camouflage, and eusocial behavior.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Inclusions in amber can preserve organisms’ organs, tissues and cells in high fidelity, and are known as “exceptionally preserved” fossils. Inclusions in amber can preserve organisms’ organs, tissues and cells in high fidelity, and are known as “exceptionally preserved” fossils. Amber inclusions are commonly thought to be mummified remains or hollow moulds, and the body cavities and walls of the moulds are mainly thought to be filled with carbonaceous material. However, this pattern may not apply to all amber inclusions. Recently, JIANG Hui, the postgraduate supervised by Profs. WANG Bo and ZHANG Haichun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, along with their collaborators from University of Bonn, Cornell College and other institutions, have proved the widespread mineralization of amber insects in Kachin amber and further reconstructed the taphonomic pathways of mineralized inclusions in amber. The study was published in Geobiology on Feb. 25. By opening a few pieces of amber and applying a variety of techniques, the researchers discovered calcification and silicification of insects in amber, which are very rare processes in the insect fossil record. The analysis showed that the mineralized insects consisted of calcite, microcrystalline quartz and macrocrystalline quartz. These minerals occupied the positions of numerous tissues and substrates, occurring as replacement minerals in organic structures and void-filling cements in cavities within the insects’ bodies. "The preservation of mineralized insects is incredible, with complete calcified compound eyes, exquisite cuticle structures, as well as skin sensillae," said JIANG Hui. In the silicified specimens, fine body structures such as the trachea and fibrous structures were preserved in the form of microcrystalline quartz, and the body cavities looked like agate geodes. Insects generally do not have biomineralized tissues made of silica or calcium carbonate. "The chemical species leading to silicification and calcification of the Kachin insects were considered to come from two sources: decomposition of their tissues in response to microbial respiration and fluid from the surrounding environment," said Prof. WANG Bo. "Homogeneous minerals in amber inclusions are also precipitated in cracks in the amber matrix surrounding the inclusions. This suggests that the fluid carrying the mineralized reaction species entered the amber along the cracks and then contacted the inclusions," said Prof. ZHANG Haichun. The pyrite in the silicified insect leg may be evidence of microbial sulfate reduction. Other processes like iron reduction and methanogenesis may have also contributed to calcification and silicification. All of these processes generate HCO3- that can react with dissolved Ca2+ to precipitate as calcite. The dissolved silica may have come from volcanic vents, hydrothermal springs, or clay diagenesis. Kachin amber occurs with volcaniclastic rock, and was preserved in shallow, nearshore depositional environments, where evaporation of seawater may have affected the dissolved silica levels. Hematite and goethite form in oxidative environments, and they may suggest diagenetic pore fluids that developed during tectonism or ground water that conduced to terrestrial weathering. The presence of organic matter in inclusions may provide reactive interfaces to promote nucleation of silica and calcite films. This new discovery indicates that mineralization played an important role in the preservation of fossils in Kachin amber, and mineralization in amber is more widespread than commonly thought. The results demonstrate that resin and amber are not closed systems. Fluids (e.g., sediment pore water, diagenetic fluid, and ground water) at various burial stages may interact with amber throughout its geologic history and affect the preservational quality and fidelity of amber inclusions.
Fig. 1 Calcified and silicified grasshopper. (Image by NIGPAS)
Fig. 2 Taphonomic model for mineralized insects in Kachin amber. (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
