Late Ordovocian paleogeography, showing similarity between equatorial position of South China plate to that of modern Galápagos Islands. The eastern equatorial Pacific cold tongue plays a vital influence on ocean-atmasphere CO2 exchange global climate patterns. Recently, a team from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Western University, Canada reported an equatorial cold-water tongue in the Late Ordovician on the basis of the evidence from paleontological, sedimentological and geochemical data. This research will be published on Geology lately. Recent paleogeographic reconstructions place the South China plate in paleoequatorial latitudes during the Late Ordovician. The northward drift of South China has been extrapolated based on paleomagnetic data, which point to a southern subtropical position in the Early Ordovician and equatorial latitudes by the mid-Silurian. This paleogeographic reconstruction, however, apparently contradicts sedimentary, faunal, and newly acquired δ18Oconodont-apatite data, which show an overall change from Early Ordovician warm water to Late Ordovician cool-water depositional environments. During the Early Ordovician, the carbonate facies of the Yangtze Platform have shallow and warm water characteristics, such as oolites of the Nantsinkuan and Fenghsiang Formations and Calathihum calcareous sponge reefs of the Hunghuayuan Formation. The brachiopod fauna is also characterized by the water-water taxa, such as Sinorthis, Finkelburgia and Tritoechia during the Early and early Middle Ordovician. In contrast, the Upper Ordovician sedimentary facies sedimentary facies and the benthic shelly faunas on the Yangtze Platform have characteristics of a cool-water origin. In the Upper Ordovician, the cool and deep-water Foliomena brachiopod fauna prevailed on the Yangtze Platform. Furthermore, a new stable-oxygen-isotopic curve, based on conodont apatite from the Ordovician succession of Yangtze Platform, shows an overall cooling trend through the Ordovician, implying a broad transition from a warm-water to a cool-water tropical environment, in contrast to the northward drift of South China from subtropical to equatorial latitude from Early to Late Ordovician. In the Ordovician, the long coastline of Gondwana had a geographic setting similar to that of modern Antarctica-South America. The vast Gondwana land mass was centered on the South Pole. With continued global cooling during the Late Ordovician and onset of the continental ice cap, the cold water along high-latitude Gondwana likely generated deep or intermediate flows, as well as surface cold currents similar to the modern Humboldt Current, bringing nutrient-laden cool waters to the shallow ocean surface to form the Cold Tongue. In addition, South China during the Late Ordovician was similar to the Galápagos Islands today in their position within an equatorial cold tongue. This paleogeographic setting would have promoted cool-water upwelling to promote high primary productivity, episodic eutrophication, and organic-rich deposits. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the Natural Science and Engineering Research Council of Canada. Reference: Jin, J.S., Zhan, R.B. & Wu, R.C. 2018. Equatorial cold-water tongue in the Late Ordovician. Geology. https://doi.org/10.1130/G45302.1
An international team found fossil Myrmeleontiformia fauna from mid-Cretaceous (approximately 100 million years ago) Burmese amber. Their findings show that Myrmeleontiformia did not gain considerable morphological novelty during the subsequent 100 million years, and their diversity seemed to result from different combinations of a limited set of character traits in a complex trade-off.
Reconstruction of two lacewing larvae (Image by YANG Dinghua) Myrmeleontiformia (antlions and their relatives) are an ancient group of lacewing insects characterized by predatory larvae with unusual morphologies and behaviors. An international team led by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and two Italian researchers found fossil Myrmeleontiformia fauna from mid-Cretaceous (approximately 100 million years ago) Burmese amber. The study was published in Nature Communications on August 22, 2018. Their findings show that Myrmeleontiformia did not gain considerable morphological novelty during the subsequent 100 million years, and their diversity seemed to result from different combinations of a limited set of character traits in a complex trade-off. This morphological stasis helped in reconstructing behaviors not preserved by a trace in the fossil record. Inference of these behaviors shed light on the ecological niche and lifestyle of extinct Myrmeleontiformia. Statistical correlation analysis strongly supported a correlation between a selection of morphological traits and two hunting strategies of these ambush predators – camouflaging and fossoriality – allowing us to reconstruct habits of extinct species. The findings suggested that fossorial specializations evolved more than once across Myrmeleontiformia from arboreal ancestors. The fossorial lifestyle of antlions was certainly one of the factors leading to their success, allowing these insects to colonize and diversify in arid habitats where they survived considerable changes in terrestrial environments during the Cretaceous lineages.
Diversity of lacewing larvae in mid-Cretaceous Burmese amber. The Burmese fossils showed that debris-carrying characterized this lineage for at least 100 million years. All of these camouflaging lacewings were equipped with elongate protuberances. The strong statistical correlation between the presence of these protuberances and camouflaging behavior demonstrated that this trait is an indicator of such behavior, even when the debris covering is not directly preserved in the amber piece together with the larvae. This research also implies that camouflaging behavior arose at least three times within Myrmeleontiformia. Camouflaging and fossoriality appear widespread across the lineage, and both behaviors allowed the predatory larvae to hide from their unsuspecting prey. Reference: Badano D.*, Engel M.S., Basso A., Wang Bo*, Cerretti P.* (2018) Diverse Cretaceous larvae reveal the evolutionary and behavioural history of antlions and lacewings. Nature Communications, DOI: 10.1038/s41467-018-05484-y
Plant-insect interactions form one of the critical bedrocks for modern ecosystems, either as pollination associations or relating to herbivory. A new mid-Cretaceous (99-million-year-old) boganiid beetle with specialized pollen feeding adaptations was reported in Current Biology on August 16, 2018. This suggests an ancient origin of beetle pollination of cycads long before the rise of flowering plants. Cycad pollen grains associated with C. cycadophilus (Image by NIGPAS) Plant-insect interactions form one of the critical bedrocks for modern ecosystems, either as pollination associations or relating to herbivory. A new mid-Cretaceous (99-million-year-old) boganiid beetle with specialized pollen feeding adaptations was reported in Current Biology on August 16, 2018. This suggests an ancient origin of beetle pollination of cycads long before the rise of flowering plants. Plant-insect interactions are largely dominated by insect-angiosperm relationships owing to the hegemony enjoyed by flowering plants since the Late Cretaceous. Gymnosperm-insect interactions, on the other hand, are far less known, particularly in terms of pollination modes. Nonetheless, insect-mediated pollination in gymnosperms and potentially prior to the rise of flowering plants is critical for understanding not only the complex biology of these plants today but also the ecology of pre-angiospermous ecosystems and the history of pollination specializations on gymnosperms. Phylogenetic analyses of the beetle and associated pollen grains conducted by Dr. CAI Chenyang from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and colleagues indicate that it was probably a pollinator of early cycads. Unlike modern wind-pollinated conifers and Ginkgo, cycads are unusual in that they are an ancient group of gymnosperms pollinated by insects, such as beetles and rarely thrips. Little is known about the early evolution of their pollination mode before the rise of angiosperms, or flowering plants, although cycads are well documented from the mid-Mesozoic. The researchers discovered a new genus and species of boganiid beetle, named Cretoparacucujus cycadophilus Cai and Escalona, 2018, preserved with many tiny cycad pollen grains and possessing specialized mandibular patches for the transport of cycad pollen. Most importantly, morphology-based phylogenetic placement of the species reveals it belongs to a clade of relict surviving genera with a disjunct distribution encompassing southeastern Africa and southwestern Australia who are also specialist pollinators of the same clade of modern cycads. Thus, both morphological and phylogenetic evidence support the determination of the fossil as a cycad-associated insect species. Ecological reconstruction of the mid-Cretaceous C. cycadophilus (Image by NIGPAS) The fossil represents the earliest definitive fossil evidence for cycad-insect interactions, and illuminates the ancient history of the establishment of complex entomophily in cycads. It also indicates a probable ancient origin of beetle pollination of cycads at least in the early stage of the Jurassic, some 176 million years ago, long before flowering-plant dominance and the radiation of their pollinators such as bees and butterflies later in the Cretaceous. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, and the Natural Science Foundation of Jiangsu province. Reference: Chenyang Cai*, Hermes E. Escalona, Liqin Li, Ziwei Yin, Diying Huang, Michael S. Engel (2018) Beetle pollination of cycads in the Mesozoic. Current Biology, DOI: 10.1016/j.cub.2018.06.036
In the past years, research groups from NIGP, Chinese Academy of Sciences have made detailed investigations for the amber sites in Myanmar. Recently, one of the groups found a new amber biota—Tilin amber biota (~72 .1Ma) from Tilin, Gangaw district, Magway region of central Myanmar. This research was published in Nature Communications on August 9, 2018.
In the past ten years, many important discoveries have been reported from Burmese amber. The well-known Burmese amber, also called Kachin amber, was from Kachin area of north Myanmar, with a geological age of ~98.8 Ma. However, very few geological investigations has been carried out for Kachin amber due to various reasons. In the past years, Dr. ZHWNG Daran and Prof. WANG Bo from the ‘Modern terrestrial ecosystem origin and early evolution’ group of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences have made detailed investigations for the amber sites in Myanmar. Recently, this group cooperated with researchers from Hong Kong, England, France and India found a new amber biota—Tilin amber biota (~72 .1Ma) from Tilin, Gangaw district, Magway region of central Myanmar. This research was published in Nature Communications on August 9, 2018.
Geology of Tilin amber In Tilin, more than 30 pits distribute along the hill baron and a typical pit is generally 1 m wide and 10–20 m deep to reach amber-bearing layers. The amber samples are preserved in coal seams beneath a grey tuff and above a yellow sandstone intercalated by conglomerates near mine surface. One tuff sample was collected just above the amber-bearing layers for LA-MC-ICP-MS U-Pb dating. Most zircon grains separated from tuff exhibited euhedral morphologies and oscillatory zoning patterns, indicating an igneous origin and no obvious sedimentary transport. A total of 15 zircons (concordance > 98%) were analyzed. Ten analyses provide the youngest age at 72.1 ± 0.3 Ma (MSWD = 0.6), which is near the Campanian-Maastrichtian boundary, and indicates a latest Campanian age for the underlying amber-bearing layers. Besides, some ammonites were found preserved in nodules of brown sandstone underlying the amber layer. They belong to the genus Sphenodiscus, which was considered to be originated from Campanian and restricted to the Maastrichtian, providing a late Campanian to Maastrichtian lower constraint for Tilin amber. Together with the radio-isotopic age for the upper constraint, Tilin amber should be within the latest Campanian age. As such, Tilin amber is at least 27 million years younger than Kachin amber.
Photograph of Tilin amber outcrop The Tilin amber fragments were analyzed using Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC-MS). Tilin amber is diagenetically altered, with diagnostic biomarkers degraded. The major pyrolysis products are aromatic compounds clearly indicating a gymnosperm origin. Although Tilin was close to Kachin in West Burma block during Cretaceous, Tilin amber is chemically clearly distinct from Kachin amber, which supposedly originated from araucarian or pinaceous trees. Angiosperms explosively diversified in mid-Cretaceous time, and became dominant in forests worldwide by the Maastrichtian. However, the gymnosperm-derived Tilin amber suggests that gymnosperms were still abundant in the latest Campanian equatorial forests. Nowadays, the forests of Southeast Asia are dominated by dipterocarps (Dipterocarpaceae, a family of angiosperm), and dipterocarp fossils and resins are present in India and Southeast Asia by the Eocene. As such, the replacement of gymnosperms by dipterocarps in Southeast Asian forests most likely occurred from the Maastrichtian to Paleocene.
U-Pb geochronology for Tilin amber Tilin amber is frequently translucent and reddish or yellowish in color. The amber pieces are usually small and seldom longer than 10 cm. A total of 52 arthropod and plant inclusions were found in 5 kg of amber. The insect fauna is composed of 12 families of eight orders, including Hymenoptera, Diptera, Hemiptera, Psocoptera, Coleoptera, Blattaria, Mantodea, and Neuroptera, and is dominated by Hymenoptera and Diptera (80% of all insects). A notable discovery is six worker ants belonging to three unknown genera of the extant subfamily Dolichoderinae, as well as a dealate female likely of the Ponerinae. The ants from Tilin amber are one of the earliest records of crown group ants, as only two Cretaceous species have been definitively assigned to extant subfamilies until now. All other ants recorded earlier in the Cretaceous belong to extinct subfamilies. Our findings provide reliable evidence for the Late Cretaceous radiation of crown group ants, and the apparent absence of sphecomyrmines suggests that the turnover from stem-groups to crown groups had already begun by the latest Campanian.
Fig. 4 Photographs of ants in Tilin amber Despite the large number of Cretaceous and Cenozoic insect faunas to date, there is a 24-million-year gap spanning from the early Campanian to the early Eocene, which dramatically hinders our understanding of the reorganization of terrestrial ecosystem and the impact of the K-Pg extinction event on the evolution of insects. Tilin amber biota yields the latest known diverse insect assemblage in the Mesozoic, and provides a unique window into a vanished tropical forest. The age, chemical components, and inclusions of Tilin amber are different from those of Kachin amber in northern Myanmar, showing a biotic change from mid-Cretaceous to Late Cretaceous. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, and the HKU Seed Funding Program for Basic Research, Reference: Zheng Daran, Chang Su-Chin*, Perrichot V., Dutta S., Rudra A., Mu Lin, Kelly R.S., Li Sha, Zhang Qi, Zhang Qingqing, Wang Jun, Wang He, Fang Yan, Zhang Haichun, Wang Bo * (2018). A Late Cretaceous amber biota from central Myanmar. Nature Communications, DOI: 10.1038/s41467-018-05650-2.
We are currently living in an icehouse world with continental glaciation in Earth’s poles that initiated at ~34 Ma. The Late Palaeozoic Ice Age (LPIA, ~340–285 Ma) is one of two major icehouses of the Phanerozoic and records the only greenhouse gas forced transition from an icehouse with complex terrestrial ecosystems to a fully greenhouse world. It was a time of low atmospheric pCO2 and high pO2, comparable to Today’s atmospheric composition, formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater 87Sr/86Sr through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the Late Palaeozoic seawater 87Sr/86Sr record remain relatively low. Recently, a new study by a team from NIGPAS and University of California–Davis presents a high-temporal-resolution and high-fidelity record of Carboniferous–early Permian seawater 87Sr/86Sr based on conodont bioapatite from an open-water carbonate slope succession in South China. The new data define a rate of long-term rise in 87Sr/86Sr (0.000035/m.y.) from ca. 334–318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in 87Sr/86Sr (0.000043/m.y.), following a prolonged plateau (318–303 Ma), is constrained to ca. 303 Ma. A major decoupling of 87Sr/86Sr and pCO2 during 303–297 Ma, coincident with the Palaeozoic peak in pO2, widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO2 from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean. The new Sr data also provide an important tool for precise stratigraphic correlation of the Carboniferous successions worldwide, which is critical to the “GSSP” works on the four Carboniferous stages. Reference: Jitao Chen*, Isabel P. Monta？ez, Yuping Qi, Shuzhong Shen, Xiangdong Wang, 2018. Strontium and carbon isotopic evidence for decoupling of pCO2 from continental weathering at the apex of the late Paleozoic glaciation. Geology, 46, 395–398. DOI:10.1130/G40093.1.
Discoveries of animal embryos have profoundly improved our understanding of the early evolution of animal development. However, the fossil record of early animal embryos is extremely rare. Recently, a team from NIGPAS and University of Southern California discovered some three-dimensionally (3-D) phosphatized animal embryos called “Archaeooides” from the basal Cambrian (about 535 million years ago) in southern Shaanxi Province, China. This research was published in Geology as a cover paper in this May. In order to reveal the morphology and internal structures of these Archaeooides fossils, the researchers applied advanced high-resolution X-ray microscopic tomography to produce 3-D reconstructions of a number of specimens. And the high quality dataset they got demonstrates that these soft-bodied fossil organisms have a thick cyst characterized by pustule-like ornaments and vesicular structures. Furthermore, a multicellular inner body undergoing palintomic cell division is enclosed by the cyst. The suite of characters, including submillimeter to millimeter scale, a palintomic pattern of cell division, and a complex cyst wall microstructure, corroborate the hypothesis that Archaeooides fossils represent the embryonic remains of animals. More specifically, the structure of the cyst wall bears close comparison to the resting cysts of living invertebrates, allowing the research to interpret Archaeooides as a diapause embryonic stage. Like the extant invertebrate diapause embryos which can survived in harsh environmental conditions, Archaeooides evolved thick, porous cyst to adapt to the temporally and spatially heterogeneous redox conditions that likely extended from the Ediacaran to the early Cambrian. The global distribution of fossil Archaeooides indicates that these environmental conditions were geographically widespread. In the light of this research, Archaeooides provides evidence of the early evolution of this metazoan life history strategy as an adaptation to adverse environmental conditions. Its widespread occurrence in both conventional and exceptional taphonomic windows provides the potential for reconstructing its embryology and, by inference, the developmental evolution of early animals and their body plans. Reference: Zongjun Yin, Duoduo Zhao, Bing Pan, Fangchen Zhao, Han Zeng, Guoxiang Li, David J. Bottjer, and Maoyan Zhu. Early Cambrian animal diapause embryos revealed by X-ray tomography. Geology, 2018.
Everyone loves a nice plate of pasta. After all, starch is the ultimate energy food. Now, we have proof that carbo-loading has been a thing for at least 280 million years. A team from NIGPAS, University of Münste, Germany and some other institutions has discovered the oldest unequivocal fossilized starch ever found, in the form of granular caps on the megaspores of a Permian-age plant called a lycopsid. The researchers also found evidence that these high energy treats may have been the power bars of early spore spreading, by attract and reward animals for megaspore dispersal. The study, published online ahead of print for the journal Geology, also provides early evidence for mutualism between plants and animals. Lycopsids were vascular plants, ancestors of modern club mosses. They thrived in the teeming swamp forests of the Permian, about 280 million years ago. The fossil megaspores of lycopsids, with remarkably well-preserved starch granule toppings, were found in Permian-age coal in northern China. Plant seeds store starch internally to nourish seedlings. But after analyzing the starch masses in the fossil megaspores using scanning electron microscopy and transmission electron microscopy, and comparing them to modern seeds, the researchers concluded that the starch caps were only outside, not inside, the megaspore. That means the starch wasn't part of the lycopsids' embryo nutrient system. Instead, the granules likely existed specifically as a spore-spreading device. Ants, birds, and mammals weren't around 280 million years ago, so the researchers speculate that snails, along with arthropods like millipedes and cockroaches, may have been the main consumers of the scrumptious starch snacks. In turn, they dispersed the lycopsid megaspores. While starch certainly existed long before the Permian, this discovery dishes up new insights into its ecological role. It can help us better understand the terrestrial animal food habit and the complexity of biotic interactions in deep geological time. Plus, it shows that starchy food was a creature comfort long before the days of fettucine. Reference: Liu, F., Bomfleur, B., Peng, H.P., Li, Q., Kerp, H. Zhu, H.C., S. 2018. 280-million-year old fossil starch reveals early plant-animal mutualism. Geology, 46(5), 423-426.
An international research team from China and US reported the fossil footprints for animal appendages in the Ediacaran Period (about 635–541 million years ago) from China, which was considered as the earliest footprint fossil record of animal.The research was published in Science Advances on June 6, 2018. Trackways and burrows excavated in situ from the Ediacaran Dengying Formation (Image by NIGP) On July 20, 1969, Neil Armstrong put the first footprint on the moon. But when did animals leave the first footprint on Earth? Recently, an international research team reported discovering fossil footprints for animal appendages in the Ediacaran Period (about 635–541 million years ago) in China. This is considered the earliest animal fossil footprint record. The research was published in Science Advances on June 6, 2018. Bilaterian animals such as arthropods and annelids have paired appendages and are among the most diverse animals today and in the geological past. They are often assumed to have appeared and radiated suddenly during the "Cambrian Explosion" about 541–510 million years ago, although it has long been suspected that their evolutionary ancestry was rooted in the Ediacaran Period. Until the current discovery, however, no fossil record of animal appendages had been found in the Ediacaran Period. Researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Virginia Tech in the United States studied trackways and burrows discovered in the Ediacaran Shibantan Member of the Dengying Formation (551–541 million years ago) in the Yangtze Gorges area of South China. The trackways are somewhat irregular, consisting of two rows of imprints that are arranged in series or repeated groups. The characteristics of the trackways indicate that they were produced by bilaterian animals with paired appendages that raised the animal body above the water-sediment interface. The trackways appear to be connected to burrows, suggesting that the animals may have periodically dug into sediments and microbial mats, perhaps to mine oxygen and food. These trace fossils represent some of the earliest known evidence for animal appendages and extend the earliest trace fossil record of animals with appendages from the early Cambrian to the late Ediacaran Period. The body fossils of the animals that made these traces, however, have not yet been found. Maybe they were never preserved. The study entitled "Late Ediacaran trackways produced by bilaterian animals with paired appendages" was published in Science Advances. The research was supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China, the U.S. National Science Foundation, and the National Geographic Society. Reference: Z. Chen, X. Chen, C. Zhou, X. Yuan, S. Xiao, Late Ediacaran trackways produced by bilaterian animals with paired appendages. Sci. Adv. 4, eaao6691 (2018).
Stratigraphic logs of the Nantuo Formation from South China The Cryogenian Marinoan glaciation (~650 to 635Ma) is the most severe icehouse event that our planet ever experienced. In South China, the Marinoan glaciation is represented by Nantuo Formation. Geological and paleomagnetic evidences indicate that ice sheets have extended to low latitude areas during this glaciation, inspiring a hard “Snowball Earth” hypothesis. The “Snowball Earth” hypothesis proposed that the Earth’s surface was completely frozen during the Cryogenian global glaciations. Global freezing resulted in the stagnation in hydrological cycle, leading to a weak continental weathering and negligible marine sedimentation. The Earth remained completely frozen until a catastrophic meltdown of the global glaciation at 635 Ma ago, resulting a rapid deposition of glacial diamictite. On the contrary, climate model proposed that surface temperature decline would enhance the rate of dissolved organic matter remineralization in deep anoxic ocean, which would increase the atmospheric CO2 concentration in turn and prevent a whole frozen Earth, leading to the “Slushball Earth” hypothesis. The Slushball Earth hypothesis postulates that ice-free ocean must exist during the Marinoan glaciation, providing a favorable condition for active hydrological cycle and marine sedimentation. Up to date, contradictions between these two hypotheses still exist. The root cause of this problem is less sedimentological study of the global glaciation. Recently, Dr. LANG Xiantuo from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, together with Prof. SHEN Bing from Peking University, carried out detailed sedimentological study of the Nantuo Formation in South China. On the basis of detailed sedimentary observations of 4 field outcrops and 2 drill cores ranging from the open shelf to basin facies, 10 lithofacies were identified in Nantuo Formation. Guided by the glacial facies model, three facies associations were synthesized: proximal glacial marine facies association, distal glacial marine facies association and non-glacial marine facies association. The vertical stacking pattern of facies associations can be correlated among the five slope and basin sections, while their correlation with the shelf section remains obscure. Facies analysis indicate two episodes of glaciation that are separated by an interglacial interval during the Nantuo glaciation. The first glacial episode is recorded by successions of coarse-grained facies (e.g., massive diamictite) in the lower part of the Nantuo Formation. The re-appearance of massive diamictite in the middle to upper part of the Nantuo Formation indicates onset of the second glacial episode. These two glacial episodes were separated by a siltstone/shale sequence of several 10s m thick, suggesting an interglacial period with limited influence from glaciation. The top of Nantuo Formation consists of gravelly siltstone/siltstone, representing the deglacial sequence of the Nantuo glaciation. The discovery of non-glacial facies association in the top of the Nantuo Formation suggests that the melting of the Nantuo glaciation was earlier than the deposition of the Doushantuo cap carbonate. This study demonstrates that the Nantuo Formation may deposit under a cyclic cold-warm climatic condition rather than a long-lasting global glaciation with the Earth’s surface being entirely frozen. This study greatly improved the sedimentologcial resolution of the Nantuo Formation. It also helps to resolve the controversial about the climate during the Cryogenian Marinoan glaciation. Schematic diagram showing the evolution of the Nantuo glaciation This study was financially supported by Natural Science Foundation of China and the Strategic Priority Research Program (B) of Chinese Academy of Sciences. Article information: Lang, X., Chen, J., Cui, H., Man, L., Huang, K.-J., Fu, Y., Zhou, C., Shen, B., 2018. Cyclic cold climate during the Nantuo Glaciation: Evidence from the Cryogenian Nantuo Formation in the Yangtze Block, South China. Precambrian Research 310, 243–255.
Earliest known halysitid tabulate coral Catenipora tongchuanensis from the middle of the Jinghe Formation (Sandbian; early Late Ordovician) at Taoqupo, north-central China Catenipora is one of the most common tabulate coral genera in the Upper Ordovician Jinghe and Beiguoshan formations on the southern margin of the Ordos Basin, north-central China. Recently, Dr. LIANG Kun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his collegues distinguished and identified the species of Catenipora using multivariate morphometric procedures. Cluster analysis based on morphological characters of coralla yields a dendrogram showing five morphospecies. The validity and distinctiveness of the morphospecies are evaluated by discriminant analysis and non-metric multidimensional scaling. To identify the species represented by the morphospecies, type specimens of species that are morphologically similar from north-central China (Sino-Korean Block) and surrounding palaeocontinents are compared with the morphospecies by non-metric multidimensional scaling and descriptive statistics. The result indicates that one morphospecies represents C. daliangensis (Yu), another represents C. subovata Yu, and the others are considered to be new species named C. tongchuanensis, C. jingyangensis and C. tiewadianensis. Catenipora tongchuanensis from the middle of the Jinghe Formation (Sandbian; early Late Ordovician) is the earliest confirmed halysitid tabulate. Species of Catenipora in north-central China (Sino-Korean Block) show the highest morphological diversity (i.e. disparity) in terms of corallite size and shape, compared with other palaeocontinents in China. Species of Catenipora in North Qilian share more common components with those from north-central China than any other palaeocontinent in China. The different morphological characteristics in terms of corallite shape and ranks in some Katian species of Catenipora from East Junggar, Mongolia, South China and Estonia suggest that some species may have originated separately during the Great Ordovician Biodiversification Event, and Catenipora is possibly polyphyletic. Paper information: Liang, K., Elias, R.J., Lee, D.-J. 2018. The early record of halysitid tabulate corals, and morphometrics of Catenipora from the Ordovician of north-central China. Papers in Palaeontology.
