Recently, Associate Professor LI Tao from Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), in collaboration with researchers from University of Bristol, University of St Andrews, and Nanjing University carried out a high-resolution deep-sea coral 234U/238U records from the Drake Passage in the Southern Ocean to track subglacial discharge from the AIS. The findings provide an important reference for predicting possible future changes in the Antarctic ice sheet. The related research results were published in Nature Communications on November 13, 2023. Subglacial discharge from the Antarctic Ice Sheet (AIS) likely played a crucial role in the loss of the ice sheet and the subsequent rise in sea level during the last deglaciation. However, no direct proxy is currently available to document subglacial discharge from the AIS, which leaves significant gaps in our understanding of the complex interactions between subglacial discharge and ice sheet stability. Recently, Associate Professor LI Tao from Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), in collaboration with researchers from University of Bristol, University of St Andrews, and Nanjing University carried out a high-resolution deep-sea coral 234U/238U records from the Drake Passage in the Southern Ocean to track subglacial discharge from the AIS. The findings provide an important reference for predicting possible future changes in the Antarctic ice sheet. The related research results were published in Nature Communications on November 13, 2023. The uranium isotopic composition of seawater is a potential tracer for subglacial discharge and thus ice-sheet stability in the past. Due to the relatively mobile nature of 234U induced by a-recoil effects, 234U is preferentially released and transported to the ocean via riverine input, resulting in an enrichment of 234U relative to 238U in modern seawater. Within debris-laden basal ice and subglacial sediments, however, recoil rejection of 234U is maintained in either basal ice or subglacial waters, thus leading to a 234U-enriched reservoir beneath the ice sheets. Given the widespread presence of subglacial lakes beneath AIS, the pool of excess 234U is expected to be considerable, and may have significantly impacted local seawater δ234U if it was released into the Southern Ocean during episodes of AIS retreat during the last deglaciation. Our findings reveal distinctively higher seawater 234U/238U values from 15,400 to 14,000 years ago, corresponding to the period of the highest iceberg-rafted debris flux and the occurrence of the meltwater pulse 1A event. This correlation suggests a causal link between enhanced subglacial discharge, synchronous retreat of the AIS, and the rapid rise in sea levels. “We further demonstrated that the enhanced subglacial discharge and subsequent AIS retreat appear to have been preconditioned by a stronger and warmer Circumpolar Deep Water”, says LI. In the study, deep-sea coral samples recovered from seamounts in the Drake Passage, including two sites to the north of the Polar front (PF) (Cape Horn and Burdwood Bank), one site aligning with PF (Sars Seamount), and two sites to the south of the PF (Interim Seamount and Shackleton Fracture Zone) (Fig.1), were precisely dated by isotope dilution U-Th disequilibrium. This comprehensive geographic coverage allowed them to investigate a range of oceanographic conditions and potential sources of δ234U anomalies. We analyzed 38 new samples from Sars Seamount 695 to 981 m, and integrated these data with 335 existing U-Th measurements to investigate the presence of δ234U anomalies in the Southern Ocean at the highest possible temporal resolution. The results reveal a general increase in Southern Ocean seawater δ234U from the last glacial period to the early Holocene, with a glacial low of ~144.0‰ (~20 ka) to a value of ~148.9‰ during the early Holocene (~10 ka), followed by a gradual decreasing trend towards a modern value of 146.8‰ (Fig.2). This deglacial increase of seawater δ234U reflects the input of excess 234U relative to 238U to the global ocean, which has been linked to the intensified physical weathering resulting from the rapid retreat of ice sheets during the last deglaciation. Superimposed on the general deglacial trend is a remarkable spike in δ234U reaching up to ~155‰ from ~15.4 to 14 ka (Fig.2). LI says, “we argued that this high δ234U signal cannot be fully explained by the advection of 234U-enriched water from other ocean basins for several reasons and is most likely caused by enhanced subglacial discharge from the AIS during this time period.” We further demonstrated that this discharge occurred synchronously with the peak in iceberg-rafted debris originating from the Weddell Sea sector of the AIS and meltwater pulse 1A (MWP-1A, ~14.65 to 14.3 ka), which provides direct evidence supporting an Antarctic contribution to MWP-1A during the last deglaciation. By comparing their deep-sea coral δ234U record with several climate proxies, we underscored that a stronger and warmer Circumpolar Deep Water may have preconditioned this rapid AIS retreat and the release of meltwater (Fig.3), thus underscoring the critical role of oceanic heat in driving major ice sheet retreat. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences. Reference: Li, T.*, Robinson, L.F., MacGilchrist, G.A., Chen, T., Stewart, J.A., Burke, A., Wang, M., Li, G., Chen, J., Rae, J.W.B. Enhanced subglacial discharge from Antarctica during meltwater pulse 1A. Nature Communications 14, 7327 (2023). https://doi.org/10.1038/s41467-023-42974-0. Fig.1 Locations of deep-sea coral samples. Fig.2 Comparison of Southern Ocean seawater δ234U record with other paleoclimatic records. Fig.3 Schematic of changes in ocean circulation, subglacial meltwater plume, and AIS.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
As one of the important innovation events in the course of life evolution, plant terrestrialization has profoundly affected and changed the Earth's ecosystem. Recently, the Early Land Plant Evolution working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe, made new progress in the field of morphology and biogeography of early terrestrial plants, based on systematic study on plant fossils from the Pridoli (late Silurian) of western Junggar, Xinjiang and global Silurian plant fossil occurrence data. The research result was published in Palaeogeography, Palaeoclimatology, Palaeoecology. As one of the important innovation events in the course of life evolution, plant terrestrialization has profoundly affected and changed the Earth's ecosystem. Recently, the Early Land Plant Evolution working group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe, made new progress in the field of morphology and biogeography of early terrestrial plants, based on systematic study on plant fossils from the Pridoli (late Silurian) of western Junggar, Xinjiang and global Silurian plant fossil occurrence data. The research result was published in Palaeogeography, Palaeoclimatology, Palaeoecology. The dispersal and biogeographic differentiation of early terrestrial plants is a part of the macroevolution of organisms, which is of great significance to understand the evolution of global ecosystems. Analysis of the fossil specimens and big data provides insights into this topic. The earliest macro-plants were reported in the Wenlockian strata of the Silurian and subsequently spread to major paleo-blocks around the world. Global Silurian plants were mainly reported from Czech Republic, Britain, Australia, South China and Xinjiang. The well-developed late Silurian strata in the Junggar Basin of Xinjiang, with abundant plant fossils, provide irreplaceable data for the study of macroevolution of early terrestrial plants. In this study, the research team had established morphological measurement criteria for early terrestrial plants, extracted morphological data using geometric morphometry, and carried out quantitative analysis and comparison of early plants. The conclusion shows that the Aberlemnia junggaria which were found in Xinjiang, despite its simple structure, but they has unique characteristics that are significantly different from other plants, for example, the terminal branches of the Aberlemnia junggaria are more sparse and narrower. This is one of the applications of morphometrics in the study of early terrestrial plants. Additionally, the research team summarized the global Silurian plant occurrence data, reconstructed the spatio-temporal distribution of Silurian plants, and recognized the global biogeographic zonation evolution through clustering, network and other analysis methods. It is concluded that two phytogeographic realms, the West Junggar-Vietnam and Laurussia-North Gondwana realms, were formed during the Pridoli Epoch. “Global phytogeographic zonation might have an earlier onset considering the widespread microfossil evidence”, says XU. This study was supported by National Key R&D Program of China and the Chinese Academy of Sciences. This study is one of series contributions to the Deep-time Digital Earth Big Science Program. Reference: Liu B.C., Zong R.W., Wang K., Bai J., Wang Y., Xu H.-H. 2024. Evolution of Silurian phytogeography, with the first report of Aberlemnia (Rhyniopsida) from the Pridoli of West Junggar, Xinjiang, China. Palaeogeography, Palaeoclimatology, Palaeoecology. 633. 111903. https://doi.org/10.1016/j.palaeo.2023.111903. . Fig.1 The holotype of new species of Aberlemnia junggaria from the Pridoli of West Junggar, Xinjiang, and morphometric parameters of the early land plants Fig.2 Box plots of morphometrical results of Aberlemnia junggaria, A. caledonica, and Renalia hueberi. Fig.3 Diversity curves of land plant (A) and macroplant phytogeographic network graphs during the Silurian (B). Spatio-temporal distribution of megaplants in the Pridoli (C).
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The systematic taxonomy of Late Carboniferous plants in China has been understudied due to the poor state of fossil preservation and the lack of in-depth research. Recently, researchers from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in cooperation with a research team from Missouri University of Science and Technology (MUST), conducted an in-depth systematic taxonomic and palaeoecological study on pemineralized fossil trunks from the Benxi Formation in Yangquan City, Shanxi Province, North China. The research results were published in the international academic journals Review of Palaeobotany and Palynology and Palaeoworld. The systematic taxonomy of Late Carboniferous plants in China has been understudied due to the poor state of fossil preservation and the lack of in-depth research. Recently, researchers from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in cooperation with a research team from Missouri University of Science and Technology (MUST), conducted an in-depth systematic taxonomic and palaeoecological study on pemineralized fossil trunks from the Benxi Formation in Yangquan City, Shanxi Province, North China. The research results were published in the international academic journals Review of Palaeobotany and Palynology and Palaeoworld. The Pennsylvanian Benxi Formation constitutes the oldest deposits of the upper Palaeozoic in the central North China Craton (NCC). Following uplift and erosion from the late Ordovician to Mississippian, crustal subsidence and sea-level rise in the Pennsylvanian enabled sediments accumulation on the NCC, the region became habitable for coastal plants. Therefore, fossil plants from the Benxi Formation represent the oldest vascular vegetation that we have known on the central NCC. The Benxi Flora is thus proposed to represent an early evolutionary stage of the Cathaysian Flora. About sixty fossil trunks with anatomical features are discovered and described from the Pennsylvanian Benxi Formation in Yangquan City. They are allochthonously preserved in fluvial channel deposits or lagoonal environment and classified into three types based on the anatomy. The first type is characterized by a solid and heterocellular pith, endarch primary xylem and pycnoxylic secondary xylem with araucarian radial tracheidal pits and araucarioid cross-field pitting. The second type contains a septate pith and a pycnoxylic secondary xylem which is comparable to that of the first type. Primary xylem is absent in the second type. The third is composed of solenoid pith, endarch primary xylem, and Agathoxylon-type secondary xylem. They are named as Damudoxylon meii Wang et Wan sp. nov., Agathoxylon leei (Sze) Wang et Wan comb. nov., and Parnaiboxylon wangi Wang et al. sp. nov. respectively. The diameter of these trunks ranges from 0.11 m to 0.55 m. The largest tree is estimated to be 29.96 m high using an allometric approach. The trunks represent the oldest and largest trees from the NCC during the Pennsylvanian due to the absence of Silurian, Devonian, and Mississippian there. The fossil evidence shows that cordaitaleans were large arborescent trees growing on clastic substrates in the Cathaysia during the Pennsylvanian. Their occurrence from the upper Pennsylvanian in North China Block suggests that the previously reported diversity of cordaitaleans, which were estimated based on impressions, is a gross underestimate. The absence of growth rings in the trunks and co-occurrence of arborescent lycopsids in the same interval, together with coal seams and bauxite around the fossil-bearing horizons, indicate that the trees grew under perhumid tropical conditions. Fallen logs acting as a seedbed for trees to aid the regeneration of vegetation is a common ecological strategy in modern forests. However, the origin, occurrence, and evolution of this nurse log strategy in the geological time is unclear. A ca. 310-million-year-old permineralized cordaitalean tree trunk from the Pennsylvanian Benxi Formation in Yangquan City, Shanxi Province, North China, with evidence of probable cordaitalean rootlets growing inside the trunk. The specimen is interpreted as a nurse log for regeneration of cordaitaleans in coastal lowlands. It provides the first glimpse of plant-plant facilitative interaction between Pennsylvanian cordaitaleans in Cathaysia. We interpret that the Pennsylvanian cordaitalean seedlings preferentially established on the fallen log owing to the ability of the rotting wood to store fresh water. The nurse log provided a stable substrate in an environment with episodic salinity and/or water table variations. In combination with previous records, it is suggested that a sophisticated terrestrial ecosystem with multiple interactions between plants and other organisms have developed on the central North China Craton no later than the Middle Pennsylvanian. This study was supported by the National Key R&D Program of China, National Natural Science Foundation of China, Youth Innovation Promotion Association, Chinese Academy of Sciences, and State Key Laboratory of Palaeobiology and Stratigraphy. References: Wang K., Huang, X., Yang W., Wang J., Wan M.*, 2023. A new gymnospermous stem from the Moscovian (Carboniferous) of North China, and its palaeoecological significance for the Cathaysian Flora at the early evolutionary stage. Review of Palaeobotany and Palynology, 311, 104858. https://doi.org/10.1016/j.revpalbo.2023.104858. Wang K., Huang, X., Yang W., Wang J., Wan M.*, 2023. First record of plant-plant facilitative interaction from the Moscovian (Pennsylvanian, upper Carboniferous) of North China. Palaeoworld. https://doi.org/10.1016/j.palwor.2023.08.002. Wang K., Yang W., Li D., Wang J., Wan M.*, 2022. Anatomically preserved cordaitalean trees from the Pennsylvanian of Yangquan City, Shanxi Province, and their implication for a perhumid climate in North China Block. Palaeoworld, 31, 294–310. https://doi.org/10.1016/j.palwor.2021.07.004. Fig.1. The column of the Upper Carboniferous and Permian in Yangquan City, Shanxi Province, and the fossil trunks in the field. Fig.2. Anatomical features of Parnaiboxylon wangi Wang et al. sp. nov., and fungal hyphae and coprolites. Fig.3. Anatomical features of Agathoxylon leei (Sze) Wang et Wan comb. nov., and the rootlets invade into the wood vertically (nurse log).
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The movement reconstruction of extinct vertebrate animals has been extensively studied, such as the gait of dinosaurs and the movement patterns of other extinct quadrupeds. How about the invertebrate animals such as extinct ants? Recently, a team led by Prof. WANG Bo from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS) proposed a set of universal research methods for reconstructing the movement of invertebrate animals. Their findings were recently published in the journal National Science Review. The movement reconstruction of extinct vertebrate animals has been extensively studied, such as the gait of dinosaurs and the movement patterns of other extinct quadrupeds. How about the invertebrate animals such as extinct ants? Recently, a team led by Prof. WANG Bo from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS) proposed a set of universal research methods for reconstructing the movement of invertebrate animals. Their findings were recently published in the journal National Science Review. In comparison to vertebrate animals, research on the movement reconstruction of extinct invertebrate animals has been limited. This is primarily due to challenges related to the preservation of invertebrate exoskeletons (which are not as easily preserved), a lack of soft tissue data, and the complex nature of appendage structures. To address this research gap, Prof. WANG Bo collaborated with Prof. WU Jianing and Dr. BAO Tong from Sun Yat-sen University, chose to focus on the movement reconstruction of the extinct hell ants from the mid-Cretaceous period. Hell ants, which lived approximately 100 million years ago, represent some of the earliest known ants. They have no apparent close relatives among modern ants and are particularly known for their unique head structures, including prominent horn-like structures and sickle-shaped mandibles. The researchers selected one species of hell ant, known as the sickle mandible ant, for their study. The movement characteristics of the sickle mandible ant's mandibles had not been extensively studied. Based on previous anatomical data from hell ant fossils, it was hypothesized that Hell ants might have used their mandibles to capture prey by moving them vertically along the horizontal plane, in coordination with their horn-like structures. However, this hypothesis had uncertainties and was based on static information, necessitating validation through the acquisition of dynamic information. To address this issue, the researchers reconstructed the movement of the sickle mandible ant's mandibles in five steps. First, they selected two different amber fossils with distinct mandible spatial configurations. Second, they created three-dimensional models of the mandibles from the fossils, accurately reconstructing the mandibles' three-dimensional shapes and anatomical structures, resulting in two high-quality 3D models. Third, based on the 3D models, the researchers detected and digitized the hidden movement clues within the fossils by comparing the 3D models of the sickle mandible ant’s mandibles in different spatial positions, quantitatively analyzing the mandibles’ three-axis movement characteristics. Fourth, they validated the kinematic feasibility through biomechanical and robotic experiments, concluding that three-axis rotation was more suitable for improving the success rate of prey capture in hell ants. Fifth, they reconstructed the predatory scenarios of the hell ants through ecological restoration. This study proposed a comprehensive approach for animating invertebrate fossils through movement reconstruction. This method, demonstrated through robotics, provides insights into the kinematics of ancient ecosystems, catalyzing the integration of paleontology with other disciplines and opening doors for a multidimensional understanding of invertebrate paleobiology. The research was support from the National Natural Science Foundation of China and Chinese Academy of Sciences. Reference: Wang Zixin, Zhang Wei, Li Jiahao, Ji Wang, Yang Yunqiang, Bao Tong*, Wu Jianing*, Wang Bo*, 2023. Animating fossilized invertebrates by motion reconstruction. National Science Review, nwad268, https://doi.org/10.1093/nsr/nwad268. Figure 1. Two amber specimens of hell ants with different mandible state Figure 2. Three-dimensional models of different spatial forms Figure 3. The triaxial motion characteristics of the mandibles were obtained by quantitative analysis Figure 4. Robotic ant head featuring triaxial rotation and its predation performance Figure 5. The predatory scenarios of the hell ants through ecological restoration
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
In many blocks on the Earth, the boundary between the Phanerozoic and Precambrian is consistently characterized by a huge sedimentary gap—the Great Unconformity. Recently, researchers from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), carried out a synthetic geochronological study for the late Ediacaran to early Cambrian strata on the southern North China craton, which provides a new perspective on the origin of the Ediacaran–Cambrian unconformity. In many blocks on the Earth, the boundary between the Phanerozoic and Precambrian is consistently characterized by a huge sedimentary gap—the Great Unconformity. Recently, researchers from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), carried out a synthetic geochronological study for the late Ediacaran to early Cambrian strata on the southern North China craton, which provides a new perspective on the origin of the Ediacaran–Cambrian unconformity. The relevant research was recently published in the international geological journal Earth and Planetary Science Letters. While this long-drawn exhumation has been argued to trigger the initiation of modern plate tectonics, the oxygenation of the ocean and atmosphere, and the Cambrian explosion. According to the thermochronologic and stratigraphic studies, the Great Unconformity has been confirmed to consist of one denudation before the Cryogenian and two exhumations during the Snowball Earth and the Ediacaran–Cambrian transitional period. While the major erosional processes before and during the Cryogenian were suggested to be associated with the Rodinia supercontinent cycle and the “Snowball Earth” event, respectively, the origin of the relatively shorter Ediacaran–Cambrian unconformity is still elusive. Multiple geological events have been proposed to be associated with the Ediacaran–Cambrian unconformity, including the final break-up of the Rodinia supercontinent, plume activity associated with the continental-scale rifting, tectonic response to the assembly of Gondwana, as well as other regional plate tectonics. However, it is still unclear how different tectonics could produce the widely comparable Ediacaran–Cambrian unconformity in different blocks. The Great Unconformity occurs widely in the North China Craton (NCC), recent studies suggested it is composed of a prolonged sedimentary break from late Paleoproterozoic/early Neoproterozoic to late Ediacaran and a short one between late Ediacaran and early Cambrian, which resembles the development pattern of the typical Great Unconformity in North America and Qaidam. In this regard, the NCC would provide us with an opportunity to understand the mechanism of the widespread exhumation that occurred from late Ediacaran to early Cambrian. Detrital zircon ages for the late Ediacaran–early Cambrian strata in the southern, western, and southeastern margins of North China craton show great similarities, with predominant age clusters peaking at ～1800 Ma and ～2500 Ma. The geochronological study reveals an apparent absence of synsedimentary zircons in the latest Ediacaran to earliest Cambrian strata, suggesting a significant tectonic quiescence in NCC. Similar situation also occurs in blocks outside the Gondwanaland in the late Neoproterozoic, indicating that the contemporaneous erosion represented by the widespread Ediacaran–Cambrian unconformity may have been dominated by a global sea-level fall, rather than regional tectonics. “However, our result does not preclude the influence of tectonism on the manifestation of the Ediacaran–Cambrian unconformity in other blocks, especially those that make up the Gondwanaland”, says SUN, “the late Neoproterozoic global sea-level fall was possibly associated with the assembly of the Gondwanaland”. This research was supported by the National Key Research and Development Program of China, the Chinese Academy of Sciences, and National Natural Science Foundation of China. Reference: Yunpeng Sun, Qing Ouyang, Xianguo Lang, Ke Pang, Chengxi Wu, Zhe Chen, Chuanming Zhou*. 2023. Global sea-level fall triggered Ediacaran–Cambrian unconformity in North China craton. Earth and Planetary Science Letters, 622: 118411. https://doi.org/10.1016/j.epsl.2023.118411. Fig.1. Outcrop photographs and representative fossils of the Ediacaran to Cambrian strata in the southern NCC. Fig.2. (A) Comparison of the Precambrian unconformities in different regions of NCC; (B) Simplified late Ediacaran to middle Cambrian paleogeographic maps of NCC. Fig.3. Hypothesized erosional history of the Great Unconformity.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
We reported the discovery of extraordinary early Cambrian (ca. 535 million years old, or Ma) microfossils that preserved the introvert musculature of cycloneuralians, a group of animals that include roundworms, horsehair worms, mud dragons, and many other creatures. The discovery added fleshy insights into early Cambrian cycloneuralians, which are closely related to arthropods, the most successful animals on Earth. An international research team led by Prof. ZHANG Huaqiao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), reported the discovery of extraordinary early Cambrian (ca. 535 million years old, or Ma) microfossils that preserved the introvert musculature of cycloneuralians, a group of animals that include roundworms, horsehair worms, mud dragons, and many other creatures. The discovery added fleshy insights into early Cambrian cycloneuralians, which are closely related to arthropods, the most successful animals on Earth. The study was published in Proceedings of the Royal Society B (Biological Sciences) on Oct. 11th. Dr. XIAO Shuhai from Virginia Tech, Dr. ERIKSSON Mats E. from Lund University, Dr. DUAN Baichuan from the First Institute of Oceanography, Ministry of Natural Resource, and Dr. MAAS Andreas from Germany were also involved in the study. The Ecdysozoa represents the most diverse bilaterally symmetric animals. It contains the Scalidophora (Kinorhyncha, Loricifera, Priapulida), Nematoida (Nematoda, Nematomorpha), and Panarthropoda (Tardigrada, Onychophora, Arthropoda). The Scalidophora and the Nematoida constitute the Cycloneuralia, whose monophyly is debated. Molecular clock estimates indicate that the Ecdysozoa may have diverged in the Ediacaran Period, but unambiguous ecdysozoan body fossils first appeared in the early Fortunian Age (ca. 535 Ma) and are represented by the total-group ecdysozoan taxon Saccorhytus and several crown-group cycloneuralian species. However, the preservation of Fortunian ecdysozoans is limited to cuticular integuments, with no labile internal tissues (e.g., muscles or nerve tissues) preserved, hampering further understanding of their functional morphology and evolutionary significance. The authors described three phosphatized and millimeter-sized specimens from the early Fortunian Kuanchuanpu Formation (ca. 535 Ma) of China. Among them, one specimen (NIGP179459; Fig. 1) is better preserved and consists of five successively larger rings that are interconnected with 19 radial and 36 longitudinal structures. The rings were compressed to certain degrees, implying that they were pliable when alive. The first ring is separate from the remaining four larger rings by a gap, and is located almost co-planarly at the center of, or slightly apical to, the second ring. The radial structures connect the first ring with the third ring, whereas the longitudinal structures extend from the third ring to beyond the fifth ring. Some longitudinal structures become more fibrous in textural appearance toward the abapical end. In the reconstruction (Fig. 2), the second to fifth rings are coaxially stacked and constitute an apically truncated cone, with hexaradially arranged internal longitudinal structures. Based on their patterns of arrangement, the fibrous texture, and the inferred pliability, the rings as well as the radial and longitudinal structures were interpreted as fossilized muscles. The preserved musculature consists of four groups of muscles, i.e., an inner circular, four outer circular, 19 radial, and 36 longitudinal muscles. This complex topology differs from that of the body-wall musculatures of basal animals such as cnidarians or ctenophores, and instead it likely represents musculature of bilaterian animals. The hexaradial symmetry imparted by the arrangement of the longitudinal muscles invites a comparison with scalidophorans, whose introvert exhibits radial symmetry both externally (i.e., longitudinal rows of scalids are radially disposed) and internally (i.e., longitudinal muscles are radially arranged). With a scalidophoran affinity, the authors interpreted specimen NIGP179459 as the anterior introvert musculature (Fig. 3a, b). The authors interpreted the second to fifth rings as body-wall circular muscles, and the 36 longitudinal structures as body-wall longitudinal muscles. The body-wall circular and longitudinal muscles constitute a muscular grid. Since similar body-wall muscular grid is present in priapulans (Fig. 3c, d) but absent in loriciferans (Fig. 3e) or kinorhynchs (Fig. 3f), specimen NIGP179459 was proposed to belong to priapulans. Considering that the priapulan-like introvert may have characterized the last common ancestor of the Scalidophora, it is also possible that specimen NIGP179459 belongs to total-group Scalidophora (Fig. 4). The total-group scalidophoran affinity of NIGP179459 is further supported by the first ring and radial structures. The authors interpreted the first ring as an introvert circular muscle, and the 19 radial structures as introvert circular muscle retractors. Introvert circular muscle is present in loriciferans (Fig. 3e), kinorhynchs (Fig. 3f), and hatching larvae of priapulans (Fig. 3d), whereas introvert circular muscle retractors are present in kinorhynchs (Fig. 3f) and hatching larvae of priapulans (Fig. 3d). Furthermore, specimen NIGP179459 lacks mouth cone and scalid associated muscles, but these muscles are common in loriciferans (Fig. 3e) and kinorhynchs (Fig. 3f). Thus, the total evidence supports a total-group scalidophoran affinity, possibly related to the priapulans (Fig. 4). Scalidophorans as represented by specimen NIGP179459 may be millimeter-sized and have an introvert with hexaradially arranged scalids, which correspond to the hexaradially arranged body-wall longitudinal muscle bundles inside. This musculature may have controlled the inversion of the introvert, and thus facilitated locomotion and feeding. The absence of long introvert retractors indicates that the animals may have very limited ability to retract their introvert, differing from modern scalidophorans that have long introvert retractors and thus can completely retract their introvert. To sum up, this paper reported for the first time the extraordinary preservation of introvert musculature of early Fortunian cycloneuralians. This work underscores the significance of internal soft anatomy in resolving the affinities of the Cambrian cycloneuralians, and supports the evolution of scalidophoran-like or priapulan-like introvert musculature in cycloneuralians at the beginning of the Cambrian Period. Reference: Huaqiao Zhang*, Shuhai Xiao*, Mats E. Eriksson, Baichuan Duan, Andreas Maas, 2023. Musculature of an early Cambrian cycloneuralian animal. Proceedings of the Royal Society B (Biological Sciences), https://dx.doi.org/10.1098/rspb.2023.1803. Figure 1. SEM images of NIGP179459 (image credited to Dr. ZHANG Huaqiao) Figure 2. Reconstructions of NIGP179459 (image credited to Dr. ZHANG Huaqiao) Figure 3. Schematic representation of scalidophoran musculatures (image credited to Dr. ZHANG Huaqiao) Figure 4. Phylogenetic position of scalidophorans represented by NIGP179459 (image credited to Dr. ZHANG Huaqiao)
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, researchers conducted phylogenetic reanalyses of the previously published anchored hybrid enrichment datasets, and solved the evolutionary relationships of extant weevil families. Weevils (superfamily Curculionoidea) represent a hyperdiverse and globally distributed group of phytophagous beetles, with approximately 62 000 described species in 5800 genera. Recently, Professor CAI Chenyang from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with colleagues, conducted phylogenetic reanalyses of the previously published anchored hybrid enrichment datasets, and solved the evolutionary relationships of extant weevil families. The result has been recently published in a Royal Society journal Biology Letters. The vast majority of weevils have a forward-facing rostrum that resembles an elephant's trunk, hence the name weevil. Weevils are divided into eight extant families, i.e. Cimberididae, Nemonychidae, Anthribidae, Belidae, Attelabidae, Caridae, Brentidae and Curculionidae. The evolutionary relationships among the families are largely resolved, with the Attelabidae, Caridae, Brentidae, and Curculionidae constituting a monophyletic group (ACBC clade), while the Cimberididae, Nemonychidae, and Anthribidae are basal lineages. However, the systematic position of Belidae is somewhat controversial, and most studies based on morphological and molecular data generally consider it as the sister group of the ACBC clade. However, a recent Anchored Hybrid Enrichment (AHE)-based phylogenomic study suggests that Belidae is sister to Nemonychidae and Anthribidae. In recent years, Prof. CAI's group has devoted itself to the research of molecular phylogenetics and timetree of insects, and used innovative methods in data curation and model selection to construct evolutionary relationships and time frameworks of several key insect lineages. Previously, the team used genome-scale data and site-heterogeneous models to construct a supertree of beetle evolution, and combined with a newly vetted set of fossil calibrations to build a more accurate beetle timetree (Cai et al. 2022). After its publication, it received extensive attention from the academic community, and is now indexed as ESI highly-cited papers and hot papers. Recently, under the supervision of Prof. Cai, Mr. LI Yanda, a doctoral student at the University of Bristol, in collaboration with colleagues from the American Museum of Natural History and the University of Bristol, compared different data filtering methods, different evolutionary models and different tree building strategies on the tree topology. Studies have shown that when appropriate data filtering is used to remove incorrectly aligned gene sequences, or when a more appropriate site-heterogeneity evolutionary model is taken, or the coalescent strategy is properly used, Belidae are always resolved as sister groups of the ACBC clade. “This result is fully consistent with the phylogenetic relationship based on morphological evidence”, CAI says, “weprovide a consistent and robust backbone phylogeny of weevils.” “More important, our analyses emphasize the significance of data curation and modelling compositional heterogeneity of molecular data in today’s phylogenomic studies”, says CAI. Financial support was provided by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the China Scholarship Council. Reference: Li, Y.-D., Engel, M.S., Tihelka, E. & Cai, C.* (2023) Phylogenomics of weevils revisited: data curation and modelling compositional heterogeneity. Biology Letters, 19, 20230307. https://doi.org/10.1098/rsbl.2023.0307 Cai, C., Tihelka, E., Giacomelli, M., Lawrence, J.F., Slipiński, A., Kundrata, R., Yamamoto, S., Thayer, M.K., Newton, A.F., Leschen, R.A.B., Gimmel, M.L., Lü, L., Engel, M.S., Bouchard, P., Huang, D., Pisani, D. & Donoghue, P.C.J. (2022) Integrated phylogenomics and fossil data illuminate the evolution of beetles. Royal Society Open Science, 9, 211771. (Google Scholar, 115 citations) Figure 1. Backbone phylogeny of weevils based on AHE amino acid dataset. Figure 2. Comparison among tree topologies generated with different models and datasets. Topology D is our preferred topology for weevil phylogeny.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Associate Research Professor LI Lixia and her collaborators from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and University of Gottingen, Germany have conducted detailed studies on taxa of important evolutionary significance of the Beigong Biota. Beigong Biota is the first unusual deep-water sponge fauna across the Ordovician-Silurian boundary in the world. It contains abundant and diverse siliceous sponges that perfectly preserved with a nearly complete sponge skeleton. In general, this sponge fauna is a mixture of “old” Cambrian type as well as quite modern ones, showing characteristics of transitional groups. Moreover, it was found in the crucial interval of sponge evolution just between the Cambrian and the Devonian. Thus, further studies about this fauna is super important to reveal a more complete picture of the origin and evolution of Phanerozoic sponges. Recently, Associate Research Professor LI Lixia and her collaborators from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and University of Gottingen, Germany have conducted detailed studies on taxa of important evolutionary significance of the Beigong Biota. Two new sponge taxa, Turgidaspongia porosa gen. et sp. nov. (Hexactinellida) and Ptilospongia hemisphaeroidalis gen. et sp. nov. (Demospongiae) were first reported from the Beigong Biota. The researchers also explored the biological, palaeoecological and macro evolutionary implications of the new taxa. The research articles were published inHistorical Biology and Estonian Journal of Earth Sciences. A new stiodermatid (Hexactinellida, Porifera) from the latest Ordovician Beigong Biota Stiodermatids are a group of hexactinellid sponges with rigid dermal layer, including 13 genera at present with the range extended from the Cambrian to Permian. It should be noted that most of the genera in Stiodermatidae were known from the Carboniferous to Permian. The specimens found earlier than the Carboniferous are mainly preserved as isolated spicules, almost no articulate specimens have been found. As for the Ordovician, even no definite isolated spicules have been reported till now. Due to the sparse fossil record, it is highly debatable that whether there is an evolutionary gap in the lineage of stiodermatids during the Ordovician. The new stiodermatid discovered from the Beigong Biota strongly suggests that there is no evolutionary gap in the lineage of stiodermatids during the Ordovician, filling the gap in the fossil records of stiodermatids during the latest Ordovician and providing a link between the Cambrian lineage and late Palaeozoic lineage. In light of the new material, all the taxa belonging to the Stiodermatidae are evaluated, combined with the restudying of its taxonomy. A large number of synonym were removed, which were previously established based on isolated spicules. The number of genera included in Stiodermatidae was reduced from 13 to 5 after reassessment. The uneven distribution of the swollen dermalia in the new species may relate to the sloughing of the dermal spicules causing by the nutrient deficiencyor seasonal development. The unique rigid skeleton structure and unusually large parietal gaps probably represent new attempts on the skeletal evolution of hexactinellids in the Palaeozoic. The earliest known fossil record of bubarids from the latest Ordovician Beigong Biota Bubarids are a popular and cosmopolitan demosponge mainly found in the modern deep-water ecosystems, reaching depths of up to 1300 meters. They are characterized by encrusting habit and a two-layer structure of choanosomal skeleton and referred to Halichondrida. At present, all the four genera included in Bubaridae are modern ones, no fossil species have ever been found. Therefore, the origin and evolution of bubarid lineage are still essentially unknown. A new halichondrid demosponge bubarid is reported from the latest Ordovician Beigong Biota. The new taxon is well-preserved with a two-layer choanosomal skeleton structure (basal layer and erect monactines layer) and three different types of megascleres (styles, strongyles, strongyloxeas), giving an excellent insight into a bubarid affinity and indicating a previously unknown group. The specimen shows almost the overall shape of the whole sponge, giving a reasonably complete knowledge of the structure of the new taxa. Thus, the new genus Ptilospongia is erected with Ptilospongia hemisphaeroidalis gen. et sp. nov as the type species. Ptilospongia probably represents the only and earliest known fossil record of bubarids, providing new information for understanding the phylogeny of bubarids, and also providing a more reliable calibration point currently available for taxonomic and molecular phylogenetic studies. The case studies mentioned above just one corner of the Beigong Biota. There are considerable number of taxa in this biota like the above two, representing numerous missing links in the evolution of the Phanerozoic sponge. So, further study on these remarkable sponges could open a new window to investigate the origin and evolution of Phanerozoic sponges This study was financially supported by the National Natural Science Foundation of China (NSFC) and Strategic Priority Research Program (B) of Chinese Academy of Sciences. Reference:Lixia Li, Joachim Reitner, Fangyi Gong, Guanzhou Yan, Rongchang Wu. 2023. A new stiodermatid (Hexactinellida, Porifera) from the latest Ordovician of Anhui, South China and its significance for searching the missing link between the Cambrian and late Palaeozoic stiodermatid lineage, Historical Biology, 35(1):116-126.https://doi.org/10.1080/08912963.2021.2024180. Lixia Li, Joachim Reitner. 2023. A remarkable new halichondrid demosponge, Ptilospongia hemisphaeroidalis, from the latest Ordovician Beigong Biota, South China. Estonian Journal of Earth Sciences, 72(1), 50–53. https://doi.org/10.3176/earth.2023.76. Fig.1 Turgidaspongia porosa gen. et sp. nov Fig.2 Reconstruction of Turgidaspongia porosa gen. et sp. nov（Image by YANG Dinghua） Fig.3 Ptilospongia hemisphaeroidalis gen. et sp. nov.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
The study reveals, although these taxa have been noted by striking similarities in reticulate venation patterns, their disparate positions on the major seed-plant phylogenies indicates, in most cases, structural similarities of meshed venation in many plant groups are likely to be superficially convergent traits adopted for similar functional benefits. A great number of fossil plant taxa are characterized by similar-shaped leaves, leaflets and anastomosing venation that have commonly been assigned to the wrong taxon where only fragmentary or ill-preserved material is available. Venation architectures and cuticular micromorphology of leaf fossils play pivotal roles in higher-level taxonomic segregation, therefore, the standardized descriptions of vein cross-connection types and stomatal features between analogical taxa are indispensable for their morphological comparisons and phylogenetic analysis. Recently, on leaf vein structure and epidermal characteristics of three morphologically similar fossil plant taxa commonly found in the Paleozoic and Mesozoic eras, which provided new insights into the systematic classification and evolutionary history of these taxa. The study provides new insights into the systematic classification and evolutionary history of these taxa. Recently, XU Yuanyuan, a PhD student at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the joint guidance of Research Professor WANG Yongdong, and Prof. Stephen McLoughlin, Swedish Museum of Natural History, carried out in-depth comparative studieds on the investigations of standardized comparisons between three morphologically similar genera, i.e., Glossopteris, Sagenopteris and Anthrophyopsis, which provided more comprehensive and new perspectives to assess whether venational pattern or stomatal characters can indicate close affinities of fossil plant taxa. This study was published in the journal of Review of Palaeobotany and Palynology. Reticulate venations occur in a broad range of plant groups dating back at least to the Pennsylvanian (Fig. 1). In many cases, anastomosing venation styles are markedly similar, and unclear whether these similarities are superficial and convergent or are genuinely homologous. Detailed observations and standardized descriptions of vein cross-connection types of Glossopteirs, Sagenopteris and Anthrophyopsis led to the functional analyses of their reticulate vein systems (Fig. 2). “Our study reveals, although these taxa have been noted by striking similarities in reticulate venation patterns, their disparate positions on the major seed-plant phylogenies indicates, in most cases, structural similarities of meshed venation in many plant groups are likely to be superficially convergent traits adopted for similar functional benefits.”, XU says. Cuticular characters, especially the stomatal complexes are arguable among the most consistent micromorphological features in fossil plants. Several traditional comparative studies and phylogenetic analysis incorporating fossil seed plants have generally proposed Glossopterids (Glossopteris), Caytoniales (Sagenopteris) and Bennettitales (Anthrophyopsis) to be close relatives of angiosperms. However, Glossopteris has perigenous and monocyclic—normally stephanocytic to actinocytic—stomata commonly protected in pits or by overarching papillae; Sagenopteris has surficial anomocytic or stephanocytic stomata with weakly modified subsidiary cells; and Anthrophyopsis has distinctive paracytic stomata consistent with those of Bennettitales (Fig. 2). This study opens up new avenues for evaluating our understanding of ancient plant taxonomy and provides a foundation for future investigations in this field. In general, the findings in this study challenge some previous notion of putatively close relationship of glossopterids (Glossopteris), Caytoniales (Sagenopteris) and Bennettitales (Anthrophyopsis), and emphasize the importance of considering ecological convergence in the interpretation of ancient plant characteristics. XU says, “While leaf characteristics have historically been used for classification, the study underscores the need for greater emphasis on the examination of reproductive organs to provide a more accurate understanding of the diversity and evolutionary history of these ancient plants.” This study was co-sponsored by the National Natural Science Foundation of China, Strategic Priority Research Program (B) of the Chinese Academy of Sciences, State Key Laboratory of Palaeobiology and Stratigraphy, Swedish Research Council and CSC. Reference: Yuanyuan Xu, Yongdong Wang*, Stephen McLoughlin*, 2023. How similar are the venation and cuticular characters of Glossopteris, Sagenopteris and Anthrophyopsis. Review of Palaeobotany and Palynology, 316, 104934. https://doi.org/10.1016/j.revpalbo.2023.104934. Fig. 1. Geological range of some representative reticulate plant fossil taxa. Fig. 2. Representative leaf fragments of Glossopteris (A–D), Sagenopteris (E–G) and Anthrophyopsis (H–J), showing leaf forms and venation styles. Scale bars for A, C, E, G, H–J = 10 mm, for B, D, F = 5mm. Fig. 3. Micromorphological features of Glossopteris (A–G), Sagenopteris (H–J) and Anthrophyopsis (K–P). Scale bars for A–D, N = 100 μm, for E–G = 10 μm, for H = 100 μm, for I = 300 μm, for J, K–L = 50 μm, for J, M, O = 30 μm, P = 20 μm.
Contact: LIU Yun, Propagandist Email:yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Associate Research ProfessorLI Qijian Li and Research ProfessorLI Yue from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and their collaborators, have reported Late Ordovician sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. Ordovician strata record a unique transition from microbial-dominated towards metazoan-dominated reefs. With their first radiation of sphinctozoan sponges during the Ordovician, they occur in thrombolites in South China, representing the initial expansion of sphinctozoan-grade sponges from level bottom to reef settings. Most previous studies mainly focused on the substantial ecological changes in the reef ecosystem. However, little is known about how abiotic carbonate precipitates link to the transition in biotic composition during the Great Ordovician Biodiversification Event. Recently, Associate Research ProfessorLI Qijian Li and Research ProfessorLI Yue from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and their collaborators, have reported Late Ordovician sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. The study entitled “Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum” has been published in Palaeogeography，Palaeoclimatology，Palaeoecology. The reefs show a three dimensional skeletal framework that is mainly constructed by Corymbospongia and Amsassia. Microbes and subsequent cementation cover the primary skeletons, enhancing the stability of the framework (Fig.1). Isopachous crystalline crusts are distinct in the boundstone of the reefs (Fig.2). Submarine synsedimentary cementation is critical to stabilization of reef frameworks and to limit mechanical erosion. Large amounts of marine cements are widely developed in modern tropical reefs, while early marine cementation has been rarely reported as an important process to promote carbonate accumulation in the early Palaeozoic reefs. The skeletal-microbial-cement reefs of the Sanqushan Formation share many similarities with reefs reported from contemporaneous strata in North China and Central Nepal. The substantial synsedimentary cementation on the seafloor found in this study provide key evidence to understand the complex feedback relationships between eco-evolutionary dynamics and early diagenesis in Late Ordovician reefs during the icehouse conditions (Fig.3). Reference: Li, Q.J.*, Na, L., Yu, S.Y., Mao, Y.Y., Kershaw, S., Yue, L., 2023. Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum. Palaeogeography, Palaeoclimatology, Palaeoecology. 624(15): 111642. https://doi.org/10.1016/j.palaeo.2023.111642. Thin section photomicrographs of the Corymbospongia-Amsassia framestone. A) Overview of the framestone, showing the scaffold structure of crowded Corymbospongia (Co) and Amsassia (Am); B) Detail of the framework constructed by the intertwined Corymbospongia (Co) and Amsassia (Am), showing exaulos tubes (red arrows) of sphinctozoans and a few small cavities (yellow triangles); C) Close-ups of the framestone showing the details of sphinctozoan chambers (yellow triangles) and exaulos tubes (Ex). Note that red triangles indicate isopachous cements in the chambers, while red triangles indicate a small cavity; D) Allonema (Al) encrusts skeletons of Corymbospongia (Co). Yellow triangles indicate the wall of a chamber. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Details of abiotic cements, taken under (A & C) stereomicroscope and (B & D) cathodoluminescence microscope. 1: isopachous cement, 2: the second generation of cement, 3: the third generation of cement, Mi: microbial fabrics. Yellow triangles show matched points between stereomicroscope and cathodoluminescence photos. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) The principal types of reefs in Ordovician (A-C). Category C possesses a macroskeletal framework. In category B, the skeletal forms are locally juxtaposed. Category A is the microbial reefs; D-E) Microscopic textures of the reefs, showing the changes in early diagenesis from Early Ordovician to Mid-Late Ordovician reefs.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
