• An endoparasitic marine tapeworm trapped in Cretaceous amber
    Cestoda, commonly known as tapeworms, is a large class of the platyhelminth phylum with about 5000 species described to date. Recently, LUO Cihang, a PhD candidate, supervised by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), collaborated with other scientists from Yunnan University, and Germany, UK, , Myanmar, reported an enigmatic fossil from mid-Cretaceous Kachin amber (about 100 million years ago), on Geology on March 22, 2024.
      Cestoda, commonly known as tapeworms, is a large class of the platyhelminth phylum with about 5000 species described to date. Recently, LUO Cihang, a PhD candidate, supervised by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), collaborated with other scientists from Yunnan University, and Germany, UK, , Myanmar, reported an enigmatic fossil from mid-Cretaceous Kachin amber (about 100 million years ago), on Geology on March 22, 2024.
      This study thus probably provides not only the first partial body fossil of a tapeworm, but also arguably the most convincing body fossil of a flatworm, providing new evidence for the early evolution of tapeworm.
      Cestoda infect all major groups of vertebrate animals including humans and livestock, and can be found in almost all marine, freshwater, and terrestrial ecosystems. Their size is variable, ranging from less than 1 millimetre to more than 30 meters in length. Tapeworms are usually characterized by adults with a scolex (grasping head), a short neck, and a segmented body formed of multiple sets of genital organs (proglottids). Their scolex typically has hooks, suckers, or hooked tentacles, which can help them clung to the alimentary tract of their hosts. Most tapeworms have an obligatory parasitic life cycle involving two or three hosts. They have no mouth and digestive tract, and absorb nutrients directly from the gut of their hosts.
      The Order Trypanorhyncha is the most speciose tapeworm group in the marine realm, and it comprises one of the most ubiquitous and readily recognized parasites of marine fish. Trypanorhynch tapeworms are characterized by a scolex bearing 2 or 4 bothria, and a unique tentacular apparatus with four evaginable tentacles adorned with hooks as extensions of tentacle sheaths inside the scolex. Their larvae infect a wide variety of marine invertebrates (like crustaceans), as well as teleosts, and their adults are found in the stomach and intestine of sharks and rays.
      Molecular clock analyses calibrated by means of host fossil data estimate that trypanorhynch tapeworms had probably originated around the Triassic/Jurassic boundary (about 200 million years old), but their own fossils have never been found. In summary, the fossil records of tapeworms are extremely sparse due to their soft tissue and endoparasitic habitats, which greatly hampers our understanding of their early evolution.
      This fossil displays unique external (armature pattern) and internal (partially invaginated tentacle and rootless hooks) features which are most consistent with the tentacles of extant trypanorhynch tapeworms that parasitize marine elasmobranchs (mainly sharks and rays). Remarkably, nearly all extant trypanorhynchs are endoparasites of marine elasmobranchs, thus our study provides an exceptional example of a marine endoparasite trapped in amber, and sheds new lights on the taphonomy of amber.
      WANG says, “we reported the first body fossil of a tapeworm.” Tapeworms are thought to originate from the mid-Paleozoic based on their molecular framework, but their fossil record is extremely scarce due to their endoparasitic lifestyle. Although supposed tapeworm eggs were reported from a Carboniferous shark coprolite, the only widely accepted fossil record before the Quaternary is restricted to eggs discovered in a shark coprolite from the Permian, suggesting that the relationship between tapeworms and elasmobranch vertebrates was established at least by then. Although a tapeworm embryo was reported inside an egg, but it is putative due to the lack of confirmed characters. The new fossil is most consistent with the tentacle anatomy of a trypanorhynch tapeworm including the hook morphology, and thus represents the first body fossil of a tapeworm from the geological past.
      The new fossil presented the most convincing body fossil of a platyhelminth. Body fossils of the platyhelminth phylum are rare, with only a few examples. The oldest putative record comes from the Devonian of Latvia: circlets of hooks with sucker discs were found on placoderm and acanthodian fish. Although the arrangement of hooks is consistent with extant monogeneans, no other body structure was found. Two cysts that resemble trematode metacercariae were reported from mid-Cretaceous Kachin amber, however, no valid morphological details were given to support this. Lastly, the body fossil of Rhabdocoela discovered in Eocene Baltic amber has been plausibly reinterpreted as air bubbles. Therefore, this find represents the most convincing body fossil of a platyhelminth that has yet been found.
      The research indicated amber can preserve the internal structure of helminths. Using high resolution micro-CT, this study discovered that inside the fossil is a folded longitudinal structure appearing to run in a spiral around the longitudinal axis and it extends to the anteriormost part. This is in accordance with the invaginated tentacle of a trypanorhynch. Meanwhile, the rootless hooks are also the same as those of trypanorhynchs. Previous research has indicated that the internal structure can be preserved intact as in extant forms, but these studies are all focused on arthropods. “Our results highlight that amber can preserve the internal structure of helminths like tapeworms on geologic time scales”, says WANG.
      The research results provided a remarkable example of a marine endoparasite trapped in amber. Some gleicheniacean trichomes and one scale insect nymph are preserved together with the partial worm fossil in the same amber specimen, clearly indicating a terrestrial or onshore environment at the time of entrapment in resin. Moreover, there are many sand grains uniformly distributed inside the amber, implying that entrapment of the fossil occurred in a sandy environment. Furthermore, previous evidence shows that Kachin amber was deposited in a near-shore environment.
      Therefore, a possible scenario can be proposed: the elasmobranch host of the tapeworm was stranded by a tide or storm, for example. The trypanorhynch had an extruded tentacle in the dying host, and its host was bitten by a higher-level terrestrial predator or scavenger; when the host was ingested by the predator, the tentacle was pulled apart from the trunk, dislodged from the intestine and came stuck to some nearby resin. “Our study further supports the hypothesis that Kachin amber was probably deposited in a paralic paleoenvironment, and also highlights the importance of amber research in paleoparasitology”, add WANG.
      This research was supported by the National Natural Science Foundation of China, the Second Tibetan Plateau Scientific Expedition and Research, and the Deep-time Digital Earth (DDE) Big Science Program.
      Reference: Luo Cihang, Palm H.W., Zhuang Yuhui, Jarzembowski E.A., Nyunt T.T., Wang Bo, 2024. Exceptional preservation of a marine tapeworm tentacle in Cretaceous amber. Geology. https://doi.org/10.1130/G52071.1.
      The fossil tapeworm from mid-Cretaceous Kachin amber (~99 Ma; million years ago) and the comparison with the tentacle of an extant trypanorhynch tapeworm. (A) Microscopic image of fossil tapeworm. (B) Micro-CT image of fossil tapeworm. (C) Scanning electron microscopy image of an extant trypanorhynch tapeworm.
      The comparison of the internal structure of the fossil (A) with the tentacle of an extant trypanorhynch tapeworm (B). Abbreviation: ivt—invaginated tentacle.
      A hypothetical ecological reconstruction of the fossil trypanorhynch tapeworm (drawn by YANG Dinghua.
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2024-03-25
  • New advances about the frequent combustion events on land during the Permian–Triassic transition in Northwest China
    Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and researchers from Nanjing University confirmed the occurrence of high-temperature wildfire events and enhanced soil erosion associated with intense volcanism during the P–T transition based on the PAHs and Hg contents at the Dalongkou section in the northern mid-latitude Northwest China, which provides important evidence for understanding the evolution of terrestrial ecosystems during the P–T transition. The results were recently published on Palaeogeography, Palaeoclimatology, Palaeoecology.
      The Permian–Triassic (P–T) mass extinction was the most severe mass extinction event of the Phanerozoic and caused catastrophic changes in the marine and terrestrial ecosystems. This environmental deterioration has been triggered by emissions of massive greenhouse and poisonous gases from the Siberian Traps large igneous province and intensive large-scale continental arc volcanism. However, the response of terrestrial ecosystems in different regions to the P–T mass extinction remains unclear.
      Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and researchers from Nanjing University confirmed the occurrence of high-temperature wildfire events and enhanced soil erosion associated with intense volcanism during the P–T transition based on the PAHs and Hg contents at the Dalongkou section in the northern mid-latitude Northwest China, which provides important evidence for understanding the evolution of terrestrial ecosystems during the P–T transition. The results were recently published on Palaeogeography, Palaeoclimatology, Palaeoecology.
      This study leveraged a combined approach to report a multi-proxy geochemical study of combustion-related PAHs and Hg concentrations in sedimentary rock samples from the classic and well-studied P–T terrestrial Dalongkou section. PAH records re?ect an obvious vegetation changeover accompanied by frequent high-temperature combustion events and enhanced soil erosion, the Hg enrichments and organic carbon-isotope provide robust evidence for volcanic activities during the P–T transition.
      Prof. ZHANG Hua from NIGPAS says, “based on biostratigraphic distributions and charcoal abundance, we hypothesize that terrestrial ecosystems experienced substantial crises and changes owing to volcanism and frequent wildfire combustion events on land during the P–T transition.” Terrestrial responses were resolved in multiple intervals. These stages exhibit a close relationship between severe climatic conditions, wildfire combustion events, and floral changeover, reflecting a progressive trend toward a drier climate triggered by volcanic activities. ZHANG add, “consequently, we proposed that increased high-temperature combustion events under worse climatic conditions contributed to terrestrial vegetation change during the latest Permian.”
      This work was funded by the National Natural Science Foundation of China and the Strategic Priority Research Programs of the Chinese Academy of Sciences.
      Reference: Jiao, S. L., Zhang, H.*, Cai, Y. F., Jin, C. F., Shen, S. Z., 2024. Polycyclic aromatic hydrocarbons (PAHs) evidence for frequent combustion events on land during the Permian–Triassic transition in Northwest China. Palaeogeogr. Palaeoclimatol. Palaeoecol. https://doi.org/10.1016/j.palaeo.2024.112152.
       
      Figure 1 GC-MS chromatograms and structures of PAHs from the Dalongkou section.
       
      Figure 2 Stratigraphic variations organic carbon-isotope, Hg concentration, DBF concentration, ∑pyPAHs concentration, clumped isotope-derived paleotemperature records, charcoal abundance and reflectance, and spore-pollen in the Dalongkou section.
       
      Figure 3 Conceptual reconstruction of environment changes in terrestrial–marine systems during the end-Permian mass extinction.
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2024-03-21
  • Fossils reveal plant–insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China
    A recent investigation of fossil plants reveals the plant–insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China. This study was completed by an international research team led by Prof. WANG Yongdong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS), with collaboration with Prof. Stephen McLoughlin from the Swedish Museum of Natural History, and published in an international journal of Frontiers in Ecology and Evolution.
      A recent investigation of fossil plants reveals the plant–insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China. This study was completed by an international research team led by Prof. WANG Yongdong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science (NIGPAS), with collaboration with Prof. Stephen McLoughlin from the Swedish Museum of Natural History, and published in an international journal of Frontiers in Ecology and Evolution.
      Plants and insects are the most diverse and ecologically important organisms in the terrestrial biosphere. Their interactions are also among the richest biotic relationships, and offer significant insights into the evolution of terrestrial ecosystem complexity through the geological record.
      The fossil plants of the late Rhaetian Xujiahe Formation and the earliest Jurassic Zhenzhuchong Formation floral assemblages provides the first data on foliar herbivory generated by terrestrial arthropods across the Triassic–Jurassic transition in the eastern Tethys (East Asia) region.
      “The damage types from the two studied fossil assemblages are collectively attributed to seven functional feeding and egg-laying categories (i.e., hole feeding, margin feeding, surface feeding, skeletonization, piercing and sucking, oviposition, and galling)", says XU Yuanyuan from the research team. Most feeding strategies are spread across the major plant groups and persist through theTriassic–Jurassic boundary, with the exception of skeletonization (a category of external foliage feeding), which was restricted to the latest Triassic within dipteridacean ferns.
      The survey reveals that the respective frequency and diversity of interactions between plants and insects prior to and following the end-Triassic mass extinction event are almost the same, despite a substantial turnover of floral components. This suggests that insect herbivores were largely able to transfer to alternative (but commonly related) plant groups during the dramatic floristic turnover and environmental changes at the end of the Triassic.
      Sporadic occurrences of foliar modifications, such as marginal cusps on pinnules of Pterophyllum and prominent ridges on the rachises of some ferns and bennettites are interpreted as adaptations for defense against insect herbivores. XU says, “A few differences in taxonomic composition and herbivory representation between the latest Triassic Xujiahe flora and the earliest Jurassic Zhenzhuchong flora are more likely to be related to collection and preservational biases rather than reflecting palaeoecological changes”.
      This preliminary assessment of herbivory across the Triassic–Jurassic boundary requires complementary studies within the Sichuan Basin, South China, to verify the regional patterns of vegetation and herbivory change in the subtropics of East Asia, and also encourage equivalent investigations from other parts of the world to clarify the global patterns of plant–insect interactions and floristic change across this major event in Earth’s history.
      This study is financially supported by the National Natural Science Foundation of China, the Swedish Research Council and CSC.
      Reference: Yuanyuan Xu, Yongdong Wang*, Liqin Li, Ning Lu, Yanbin Zhu, Zhuanli Huang, & Stephen McLoughlin*, 2023. Plant-insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China. Frontiers in Ecology and Evolution, 11: 1338865. https://doi.org/10.3389/fevo.2023.1338865.
      Figure 1. Diversity of damage types among the various plant groups and the proportion of functional feeding groups represented within the uppermost Triassic and Lower Jurassic assemblages.
      Figure 2. Examples of various damage types on different plant groups from Member VII of the Xujiahe Formation.
      Figure 3. Examples of various damage types on different plant groups from the Bed 2 of the Zhenzhuchong Formation.
      Figure 4. Examples of physical defenses on some leaf fragments. (A, B) Showing prominent teeth on the apices of pinnules of Pterophyllum ctenoides. (C) Showing obvious thickening ridges (wrinkles) on the rachis of Pterophyllum ctenoides.
       
       
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2024-02-04
  • Fossils from North China indicate eukaryotes first acquired multicellularity by at 1.63 billion years ago
    On January 24, 2024, a research team led by Professor ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NGIPAS), published their latest research finding of ~1.63-billion-year-old multicellular fossils from North China, on the prestigious journal Science Advances.
      On January 24, 2024, a research team led by Professor ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NGIPAS), published their latest research finding of ~1.63-billion-year-old multicellular fossils from North China, on the prestigious journal Science Advances.
      These exquisitely preserved microfossils were considered as currently the oldest record of multicellular eukaryotes. The study is another breakthrough after their finding of decimeter-sized eukaryotic fossils in the Yanshan area, North China, and extends back the emergence of multicellularity in eukaryotes by about 70 million years.
      All complex life on Earth, including diverse animals, land plants, macroscopic fungi and seaweeds, are multicellular eukaryotes. Therefore, multicellularity is key for eukaryotes to acquire organismal complexity and large size, and often regarded as one major transition in Earth’s life history by scientists. However, it is still poorly understood when eukaryotes first evolved this innovation in their deep evolutionary history.
      Fossil records with convincing evidence show that eukaryotes with simple multicellularity already appeared at 1.05 billion years ago, including red and green algae, and putative fungi. Older records claimed to be multicellular eukaryotes, but most of them are controversial due to their simple morphology and lack of cellular structure.
      “The newly discovered multicellular fossils are from the late Paleoproterozoic Chuanlinggou Formation of ~1635 million year old. They are unbranched uniseriate filaments made up of two to more twenty large cylindrical or barrel-shaped cells, with diameter of 20-194 μm, and incomplete length up to 860 μm. These filaments show a certain degree of complexity based on their morphological variation”, says MIAO Lanyun from theresearch team.
      Filaments can be constant or tapering throughout the entire length, or only tapering at one end. Morphometric analyses demonstrate their morphological continuity which suggest they should represent a single biological species, instead of discrete species. They are named as Qingshania magnifica, 1989, a form taxon with similar morphology and size, and also described from the Chuanlinggou Formation.
      One particularly important feature of Qingshania, is the round intracellular structure (diameter 15-20 μm) in some cells. These structure are comparable to asexual spores known in many eukaryotic algae, indicating Qingshanialikely reproduced by spores.
      In modern life, uniseriate filaments widely occur in both prokaryotes (bacteria and archaea) and eukaryotes. The combination of large cell size, large range of filament diameter, morphological variation and intracellular spores, demonstrate the eukaryotic affinity of Qingshania, as no known prokaryotes can be such complex. Filamentous prokaryotes are commonly very small, about 1-3 μm in diameter, and distribute in more than 147 genera of 12 phyla. Some cyanobacteria and sulfur bacteria may reach large size up to 200 μm thick, but these large prokaryotes are very simple in morphology with disc-shaped cells and do not reproduce via spores.
      The best modern analogues are some green algae, although filaments also occur in other groups of eukaryotic algae (red algae, brown algae, yellow algae, charophytes, etc.), as well as fungi and oomycetes. MIAO add, “this indicates Qingshania was most likely photosynthetic algae, probably belonging to extinct stem group of Archaeplastids (a major group consisting of red algae, green algae and land plants, as well as Glaucophytes), although its exact affinity is still unclear.”
      In addition, they have conducted Raman spectroscopic investigation to test the eukaryotic affinity of Qingshania, from the perspective of chemical composition, and used 3 cyanobacterial taxa as comparison. Raman spectra revealed 2 broad peaks characteristic of disordered carbonaceous matter, and the estimated burial temperatures using Raman parameters range from 205 to 250 °C, indicating low degree of metamorphism. Principal component of analysis (PCA) of Raman spectra sorted Qingshania and cyanobacterial taxa into two distinct clusters , indicating Qingshania has different organic matter from those of cyanobacterial fossils, further supporting the eukaryotic affinity of Qingshania.
      At present, the oldest unambiguous eukaryotic fossils are unicellular forms from late Paleoproterozoic sediments (~1.65 billion years ago) in North China and Northern Australia. Qingshania appeared only slightly later than them, indicating eukaryotes acquired simple multicellularity very early in their evolutionary history.
      As eukaryotic algae (Archaeplastids) originated after the last eukaryotic common ancestor (LECA), the discovery of Qingshania further supports the early appearance of LECA in late Paleoproterozoic (which is consistent with many molecular clock studies), rather than at late Mesoproterozoic of about 1 billion years ago, if Qingshaniawas truly algal in nature.
      Professor Andrew Knoll from Harvard University and Professor QU Yuangaofrom the Institute of Deep-sea Science and Engineering, CAS, joint the study. This study was jointly funded by the National Key Research and Development Program of China, the National Natural Science Foundation of China and the Innovation Cross-Team of the CAS.
      References:Miao, L., Yin, Z., Knoll, A.H., Qu, Y., Zhu, M.*, 2024. 1.63-billion-year-old multicellular eukaryotes from the Chuanlinggou Formation in North China. Science Advances. https://www.science.org/doi/10.1126/sciadv.adk3208.
       
      Multicellular fossil Qingshania from the Chuanlinggou Formation. Scale bar equals 100 μm for F-H and K, and 50 μm for the rest (Miao et al., 2024b).
      Multicellular fossil Qingshania with a round intracellular structure interpreted to be spore. Scale bar equals 50 μm for A, C, D and F (Miao et al., 2024b).
      Morphometric analyses of Qingshania (A-D), filament size frequency distribution (F), and comparison with modern large eukaryotic and prokaryotic filaments (A, B, E). Chaetomorpha and Urospora are green algae; Oscillatoriais a cyanobacterium; Beggiatoa and Thioploca are sulfur bacteria (Miao et al., 2024b).
      Raman analyses of Qingshania and 3 cyanobacterial taxa (Miao et al., 2024b).
      Principal component analysis (PCA) of Raman spectra of Qingshania and 3 cyanobacterial taxa (Miao et al., 2024b).
      Simplified eukaryotic tree (A) and representative early eukaryotic fossils (B). In eukaryotic tree, grey dash lines represent stem group eukaryotes. Solid lines denote crown group eukaryotes (LECA plus its descendants). Grey bars at nodes display the estimated age range of divergence of major branches from a molecular clock study (Parfrey et al., 2011, PNAS). Scale bar in the green algal fossil equals 500 μm; the rest are 50 μm (Miao et al., 2024b).
       
       
      Contact:
      LIU Yun, Propagandist
      Email:yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2024-01-25
  • The early evolution of cicadas revealed by new fossils and analyses
    Recently, Dr. JIANG Hui supervised by Professors WANG Bo and ZHANG Haichun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led a collaborative cicada study with scholars from several countries. Their research aimed to clarify the early evolutionary history of Cicadoidea fossils, the phylogenetic relationships between Mesozoic fossils and extant Cicadoidea, the macroevolution of body structure adaptations, and their relationship with environmental changes. The related findings were recently published in Nature Communications.
      Recently, Dr. JIANG Hui supervised by Professors WANG Bo and ZHANG Haichun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led a collaborative cicada study with scholars from several countries. Their research aimed to clarify the early evolutionary history of Cicadoidea fossils, the phylogenetic relationships between Mesozoic fossils and extant Cicadoidea, the macroevolution of body structure adaptations, and their relationship with environmental changes. The related findings were recently published in Nature Communications.
      Cicada, here referring to the superfamily Cicadoidea, is well-known for its evolution of sound production system, exceptional long-term subterranean habits, and symbolic attributes and utility in research that widely exists in culture, life, and science. Extant Cicadoidea includes the globally widespread Cicadidae, commonly known as true/singing cicadas, and relictual Tettigarctidae, found only in Australia and colloquially known as hairy cicadas.
      Currently, the earliest fossil of Cicadoidea was found in the Triassic. All Mesozoic (approximately 252 to 66 million years ago) Cicadoidea fossils have traditionally been classified into Cicadidae and Tettigarctidae based on a few distinct and conservative morphological features. However, this direct assignment of Mesozoic fossils to modern taxa may overlook the role of unique and transitional features provided by fossils in tracking their early evolutionary paths.
      This study explores the phylogenetic relationships of fossil and extant Cicadoidea groups for the first time. It reveals that Mesozoic Cicadoidea fossils include stem cicadoids, stem tettigarctids, and stem cicadids. Some Mesozoic fossils previously classified as Tettigarctidae might actually be closer to modern Cicadidae phylogenetically. The clades of Cicadidae and Tettigarctidae might have diverged at or by the Middle Jurassic. Due to preservation issues, the classification of insect fossils often relies on the preserved partial morphological features.
      This study conducted a morphological analysis of the partial structures of adults and nymphs, such as wings, non-wing body parts, and nymphal legs, to compare subtle continuous morphological changes with classification and phylogenetic outcomes. The research found that specialized homologous structures in insect fossils might contain previously overlooked identifiable transitional variations.
      An in-depth examination of these continuous morphological changes can provide a more precise understanding of the impact of spatiotemporal changes on morphological evolution and further clarify patterns of macroevolution. For example, changes in the head and labium might reflect resistance adaptations due to feeding pressures from host plant changes. Additionally, changes in the thoracic notum, and alterations in wing venation and outline, may indicate the evolution of flight muscles and capabilities. Changes in the head and thorax can also be quantified and compared.
      Producing sounds is a vital communication method for many animals. Modern Cicadidae species can produce the loudest sounds among insects, reaching nearly 120 decibels via tymbal mechanisms. In contrast, Tettigarctidae communicate with subtler vibrational signals transmitted through the substrate, lacking the ability to produce loud sounds. The varied sound-producing mechanisms between Cicadidae and Tettigarctidae ignite curiosity about the initial evolution of their acoustic structures and behaviours.
      In this study, tymbals were identified in all Mesozoic cicadoid stem groups, preserved in both male and female specimens. This is the first identification of tymbal structures in Cicadoidea fossils, capturing this communication method in the fossil record. The majority of relatively intact fossils lacked elements for intricate sound production and auditory systems, suggesting mid-Cretaceous cicadoids may have relied on substrate-transmitted vibrations for communication, rather than producing or perceiving high-decibel songs.
      Additionally, there are instances where the discovery of tymbal muscles and an abdominal cavity in a fossil, alongside preserved tracheae, flight muscles, and Marplesian tubes, suggests the possibility of an inherent abdominal cavity and resonating abilities similar to those found in the abdomens of modern singing cicadas. Consequently, the study posits another hypothesis: certain mid-Cretaceous Cicadoidea groups may have generated sounds louder than substrate-transmitted vibrations. Anyway, compared to modern singing cicadas, the species of Cicadoidea might have been relatively silent for the majority periods of Mesozoic.
      This study also reports the oldest known Cicadoidea nymph and exuviae fossils from mid-Cretaceous Kachin amber. The prominently powerful fossorial forelegs of these nymphal fossils, akin to modern cicadas, suggest similar behaviours and robust capabilities for digging, soil transportation, and subterranean living. Cicada nymph and adult fossils show distinct ecological niches and survival strategies, with a notable shift from underground root feeding to above-ground stem feeding.
      Evidence of root feeding is infrequently found in fossils. However, cicada nymph fossils with specialized digging forelegs suggest this behaviour. This subterranean lifestyle presumably conferred a survival benefit, enabling extended underground habitation for cicada nymphs.
      This study also examines the occurrence of root feeding among arthropods in the fossil record. Given the adult and nymph Cicadoidea fossils from Kachin amber and the multitude of adult fossils from the Middle Jurassic Daohugou deposit, it's evident that mid-Mesozoic Cicadoidea demonstrated distinct life stage niches, facilitated biomass transfer from underground to above-ground, and influenced ecosystems in a manner akin to their modern cicadas.
      This work is jointly funded by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
      Reference: Jiang Hui, Szwedo J., Labandeira C.C., Chen Jun, Moulds M.S., Mahler B., Muscente A.D., Zhuo De, Nyunt T.T., Zhang Haichun, Wei Cong, Rust J., Wang Bo (2024) Mesozoic evolution of cicadas and their origins of vocalization and root feeding. Nature Communications, 15: 376. https://doi.org/10.1038/s41467-023-44446-x. 
      Adults, final instar nymph, and exuviae of Cicadoidea fossils in Kachin amber of Myanmar.
      Digital reconstructions from micro-CT data reveal a diverse array of morphologies throughout the evolution of Cicadoidea.
      Specialized fossorial forelegs of fossil and extant cicada nymphs.
      Phylogenetic and morphological analyses-based relative relationships discrimination and reconstruction.
      Life reconstruction of cicadas in the Mesozoic forest.
       
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2024-01-12
  • Reinvestigations on the unique fossil Dicksonid fern from the Jehol Biota
    The research team revised the taxonomic characteristics of Xiajiajienia based on morphological features and discussed its potential taxonomic position within the Dicksoniaceae from a phylogenetic perspective. The results of this study have recently been published in the international peer-reviewed journal Cretaceous Research.
      The family Dicksoniaceae, one of the most important floristic elements of the Mesozoic, had two flourishing periods which is in the Middle Jurassic and the Early Cretaceous. Although there are still arguments about the classification of some taxa, fossil genera that yield cup-shaped or bivalvate indusia in sori have been considered members of the family Dicksoniaceae.
      Xiajiajienia Sun, Zheng, and Mei is a unique fossil taxon within the fern family Dicksoniaceae. It was originally described by Professor SUN Ge et al. on the basis of fossils discovered in Xiajiajie, Jilin and Huangbanjigou, Liaoning provinces, leading to the establishment of a new genus. In recent years there have been few reports on Xiajiajienia due to the lack of fossil specimens. Some of the sterile organs of the fossil specimens have been assigned to Cycadophyte, specifically as part of the genus Rehezamites by Pott, McLoughlin, Lindstrom, Wu and Friis.
      Led by Professor WANG Yongdong of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), an international team recently conducted a systematic investigation on newly discovered material of the Xiajiajienia mirabila from the Jehol biota in wetsrn Liaoning Province. The research team revised the taxonomic characteristics of Xiajiajienia based on morphological features and discussed its potential taxonomic position within the Dicksoniaceae from a phylogenetic perspective. The results of this study have recently been published in the international peer-reviewed journal Cretaceous Research.
      The genus Xiajiajienia has marginal borne sori with bivalvate indusia in the fertile pinnule which were consistent with the diagnosis of Dicksoniaceae; but has unlobed drepaniform sterile pinnules, which were distinguishable from other genera in Dicksoniaceae.
      The newly found fossil specimen of Xiajiajienia was preserved as the impression with counterpart, and was collected from Huangbanjigou of Jianshangou Bed of the Jehol Biota, with fine preservation of delicate structures of sterile and fertile pinnules. The specimens provide the evidence of a "partially fertile pinna" that existed in Xiajiajienia. Fertile segments are slightly contracted and reduced. Sori are marginally borne, with distinct bivalvate indusia. Sterile pinnules are unlobed, drepaniform to long tongue-shaped, strongly decurrent.
      Based on the characteristics of the fertile pinnules, the research team discussed the phylogenetic position of Xiajiajienia using phylogenetic analysis methods combined with the constraints of the Molecular Scaffold of modern ferns and assessed its relationship to Dicksoniaceae, Dennstaedtiaceae, Lindsaeaceae, as well as other ferns with similar morphological characteristics of sorus. The results show that Xiajiajienia is more closely related to the Dicksoniaceae, and some fossil species of the genus Dicksonia L'Héritier than to the common Mesozoic fern Coniopteris Brongniart.
      In addition, based on the palaeoclimate reconstructions of the Jehol Biota in previous studies, the research team hypothesized that the growth environment preference of Xiajiajienia was a mild climate with seasonal variations, similar to that of certain modern Dicksonia species, with some regional moisture requirements.
      This work is jointly funded by the National Natural Science Foundation of China , the Strategic Priority Research Program (B) of the Chinese Academy of Sciences , the State Key Laboratory of Palaeobiology and Stratigraphy, the ICDP Integrated Understanding of the Early Jurassic Earth System and Timescale (JET) projects (IGCP 632, IGCP 655 and IGCP 739), and the China Scholarship Council.
      Reference: ZHANG, L., WANG, Y., RUHL, M., ZHU, Y. and LI, H. 2023. Re-investigations of the fossil fern Xiajiajienia mirabila (Dicksoniaceae) based on new material from the Lower Cretaceous of western Liaoning, China. Cretaceous Research, 149, 105543. https://doi.org/10.1016/j.cretres.2023.105543.
      Figure 1. Three types of pinnae of Xiajiajienia mirabila, partly fertile pinna (A-B), sterile pinna (C), and fertile pinna (D), all at a scale of 1 cm; subfigs. E, F, and G are partial enlargements of the sterile pinna of Figs. A, B, and C, respectively, showing their drepaniform and unlobed morphology, at scales of 2 mm, 2 mm, and 5 mm, respectively.
      Figure 2. Fertile pinnules and sori comparisons between Xiajiajienia mirabila and modern Dicksonia (D.lanata), showing characteristics of marginal borne sori with bivalvate indusia in the fertile pinnule.
      Figure 3. Sketch reconstructions of Xiajiajienia mirabila. A, the sterile pinna; B, the sterile pinnules; C, sorus, spore, and possible sporangium; D, fertile pinna (fully); and E, fertile pinna (partly).
      Figure 4. Majority-rule consensus tree of Xiajiajienia and its related groups by a cladistic analysis of reproductive structure characters.
       
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2023-12-26
  • Earliest known fossil mosquito from Lebanon suggests males were bloodsuckers
    Dany Azar, from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS) and the Lebanese University, has reported in Current Biology on December 4, 2023, which have found the earliest known fossil mosquito in Lower Cretaceous amber from Lebanon. What’s more, the well-preserved insects are two males of the same species with piercing mouthparts, suggesting they likely sucked blood.
      Dany Azar, from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS) and the Lebanese University, has reported in Current Biology on December 4, 2023, which have found the earliest known fossil mosquito in Lower Cretaceous amber from Lebanon. What’s more, the well-preserved insects are two males of the same species with piercing mouthparts, suggesting they likely sucked blood.
      “Lebanese amber is to date the oldest amber with intensive biological inclusions and it is a very important material as its formation is contemporaneous with the appearance and beginning of radiation of flowering plants, with all what follows of co-evolution between pollinators and flowering plants” said D. Azar.
      Among modern-day mosquitos, only females are hematophagous, meaning that they use piercing mouth parts to feed on the blood of people and other animals.
      “Molecular dating suggested that the family Culicidae arose during the Jurassic, but previously the oldest record was mid-Cretaceous,” said André Nel of the National Museum of Natural History of Paris (Muséum National d’Histoire Naturelle de Paris). “Here we have one from the early Cretaceous, about 30 million years before.”
      The Culicidae family of arthropods includes more than 3,000 species of mosquitoes. Female mosquitoes are notorious for their blood-feeding ways, which has made them a major vector for spreading infectious diseases. Hematophagy in insects is thought to have arisen as a shift from piercing-sucking mouthparts used to extract plant fluids. For example, blood-sucking fleas likely arose from nectar-feeding insects. But the evolution of blood-feeding has been hard to study in part due to gaps in the insect fossil record.
      In the new study, researchers describe two male mosquitos with piercing mouthparts, including an exceptionally sharp, triangular mandible and elongated structure with small, toothlike denticles. The new findings suggest that male mosquitoes in the past fed on blood as well, according to the researchers. They also help to narrow the “ghost-lineage gap” for mosquitoes, they say.
      They report that the mosquitos’ preservation in amber extends the definitive occurrence of the mosquito family of insects into the early Cretaceous. It also suggests the evolution of hematophagy was more complicated than had been suspected, with hematophagous males in the distant past.
      In future work, Nel says they want to learn more about the 'utility' of having hematophagy in Cretaceous male mosquitos. They’re also curious to explore “why this no longer exists,” he says.
      This work was supported by the National Natural Science Foundation of China..
      Reference: Dany Azar, Andre Nel, Diying Huang, Michael S. Engel, The earliest fossil mosquito, Current Biology (2023), https://doi.org/10.1016/j.cub.2023.10.047.
      Dorsal view of male mosquito in amber.
      Detail of mouthparts using a confocal microscope; scale bar, 10 μm
      Age recovery of fossil mosquito in Lower Cretaceous amber from Lebanon
       
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2023-12-05
  • Deep-sea Coral Evidence for Enhanced Subglacial Discharge from Antarctica during Meltwater Pulse 1A
    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
    2023-11-15
  • New advances in morphology and biogeography of early terrestrial plants
    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
    2023-11-15
  • Permineralized fossil trunks reveal a complex terrestrial ecosystem in North China Block during the Pennsylvanian
    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
    2023-11-07