The Helmetiids is a group of weakly sclerotized Cambrian arthropods that have aroused interest on account of their trilobite affinities. Because of edge-to-edge tergite articulations and the supposed shared derived character of dorsoventral mismatch, they are considered closely related with trilobites as their possible sister taxon. The first species to be described was Helmetia expansa Walcott, 1918 from the middle Cambrian Burgess Shale Biota, but details of the ventral morphology of this species are still poorly known. Among exceptionally well-preserved arthropods from the Chengjiang Biota, Helmetiids are represented with five species: Kuamaia lata Hou, 1987; Kuamaia muricata Hou and Bergstr？m, 1997; Rhombicalvaria acanthi Hou, 1987; Saperion glumaceum Hou, Ramsk？ld and Bergstr？m, 1991, and Skioldia aldna Hou and Bergstr？m, 1997. Together these six species comprise a substantial proportion of the taxon Helmetiida. Recently, Dr. ZHAO Fangchen from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues described a new helmetiid arthropod, Haifengella corona n. gen. n. sp., from the Chengjiang Lagerst？tte in Journal of Paleontology. The discovery provides new materials for the evolution and species diversity of helmetiids. This research was supported by Chinese Academy of Sciences, National Basic Research Program of China and the National Natural Science Foundation of China. Related information of this paper: Zhao Fangchen, Hu Shixue, Zeng Han, Zhu Maoyan. 2014. A new helmetiid arthropod from the early Cambrian Chengjiang Lagerst？tte, Southwest China. Journal of Paleontology, 88(2): 367-370.
Haifengella corona
Haifengella corona and the other five species of Helmetiids
Microbialites and microbial carbonates, formed during growth of microbes by their calcification and binding of detrital sediment, have become one of the most popular geological topics recently. They occur throughout the entire geological history, and especially flourished during the Meso- to Neoproterozoic, Cambrian–Ordovician, Late Devonian–Early Carboniferous, and Early Triassic. Flourish and decline of microbialites and microbial carbonates are closely related to major geological events, paleoclimate, and paleoceanography. Therefore, studies on these microbial-induced sediments are important with respect to revealing paleoceanographic, paleoclimatic, and paleoecological conditions. They also bear important economic significances due to their complex structures and biogenic origins. Recently, Dr. CHEN Jitao from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleague provide review and present new views on current progress and problems in the study of microbialites and microbial carbonates, based on literature investigations and their recent researches. The proposed that microbial carbonates can be classified into two categories: stabilized microbial carbonates (i.e., carbonate microbialites, such as stromatolites and thrombolites) and mobilized microbial carbonates (i.e., microbial carbonate grains, such as oncoids and microbial lumps). Various texture, structures, and morphologies of microbialites and microbial carbonates hamper the systematic description and classification. They also provide a practical classification on various structures of microbialites. Moreover, complex calcification pathways (mostly extracellular) and diagenetic modifications further obscure the origin of some microbialites and microbial carbonates. Recent findings of abundant sponge spicules in previously identified “microbialites” challenge the traditional views about the origins of these “microbialites” and their implications to reef evolution. On the other hand, microbialites and microbial carbonates are not always flourished in the aftermath of extinction events, which, together with other evidences, suggests that they are affected not only by metazoans but also by other geological factors. Their growth, development, and demise are also closely related to sea-level changes, due to their dependence on water depth, clarity, nutrient, and sunlight. Detailed studies on microbialites and microbial carbonates throughout geological history would certainly help understand causes and effects of major geological events as well as the co-evolution of life and environment. Related information of this paper: Chen Jitao, Lee Jeong-Hyun, 2014. Current progress on the geological record of microbialites and microbial carbonates. Acta Geologica Sinica (English Edition), 88 (1), 260–275.
Representative photographs of various microbialites and microbial carbonates. (a) Irregular to domal stromatolite, Cambrian Series 2, Laiwu region, Shandong, China. (b) Thrombolite with irregular, dark-gray microbial clots, Cambrian Series 3, Jinan region, Shandong, China. (c) Dendrolite with bush-like structures, Cambrian Series 3, Jining region, Shandong, China. (d) Leiolite with aphanitic texure, Cambrian Series 3, Laiwu region, Shandong, China, which was firstly recognized by Woo (2009). (e) Microbial laminites with desiccation crack, Cambrian Series 3, Linyi region, Shandong, China. (f) Oncoid with spheroidal shapes and crudely-laminated cortex, Cambrian Series 3, Jinan region, Shandong, China.
Different scales of microbialite structures and morphology. (a) The four investigation scales of microbialites (modified after Shapiro, 2000). (b) Amended investigation scales of microbial structures and morpholog
The Progymnospermopsida, being characterized by pteridophytic free-sporing reproduction but gymnospermous secondary vascular tissues, is subdivided into three orders: Aneurophytales, Archaeopteridales and Protopityales. Among them Aneurophytales is thought to be the most primitive. Genera in Aneurophytales established based on both morphological and anatomical characters include Tetraxylopteris Beck 1957, Rellimia (Dawson) Leclercqet Bonamo 1973, and Aneurophyton Kr？usel et Weyland 1923. The diagnostic characters of Aneurophyton come mainly from the type species, A. germanicum Kr？uselet Weyland 1923, widely reported from the Middle Devonian of Euramerica (e.g. Serlin and Banks 1978; Schweitzer and Matten 1982). Recently, Dr. JIANG Qing and her colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences described a new species Aneurophytondouisp. nov. (Aneurophytales, Progymnospermopsida) from the late Middle Devonian Hujiersite Formation of Hoxtolgay, Xinjiang, northwest China, as a plant with at least four orders of axes and ultimate units (vegetative appendages/fertile organs). Spines cover the surface of all orders of axesand ultimate units. The second-order axes and the vegetative appendages are closely inserted in pairs and helically arranged. From the second order, axes of subsequent orders are produced by bifurcation. The vegetative appendages are unwebbed and up to three times dichotomous. The fertile organ is pinnate, and thefertile organ axes are opposite or subopposite with adaxial, elliptical sporangia. This is the first formal report of Aneurophyton beyond the coasts of the Rheic Ocean. West Junggar, the locality of present species of Aneurophyton, played a key role in the dispersal of Aneurophytales in the Middle Devonian. The paper was published in International Journal of Plant Sciences. Related information of this paper: Jiang Q, Wang Y, Xu H-H*, Feng J. 2013.A new species of Aneurophyton(Progymnospermopsida) from the Middle Devonian of West Junggar, Xinjiang, China, and its paleophytogeographical significance.International Journal of Plant Sciences. 174: 1182-1200)
The Ediacara biota (580–541million years old) marks the first appearance of macroscopic and architecturally complex organisms in Earth history. Although Ediacara fossils have been known from nearly 30 localities on all major continents except Antarctica, they are almost exclusively preserved in sandstones. A new discovery, announced recently in Scientific Reportsby scientists from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and the Department of Geosciences at Virginia Tech, shows that some classical elements of the Ediacarabiota could live in carbonate environments and can be preserved in marine limestones. The new fossils will fundamentally change the ecology and preservation of Ediacara fossils. Ediacara fossils predate the massive radiation of animals during the Cambrian Explosion (541–520 million years ago). Thus, they have the potential to illuminate the prelude to the Cambrian Explosion. However, these fossils are open to wide speculations. Some scientists believe that the Ediacara biota includes marine animals representing the precursors to the Cambrian Explosion, whereas others see Ediacara fossils as lichens living on land. The new fossils were discovered from the ~550 million-year-old Dengying Formation in the Yangtze Gorges area, and include several widespread Ediacara elements such as Hiemalora, Pteridinium, Rangea, and Charniodiscus, as well as a new annulated tubular fossil that was named Wutubusannularis after Wuhe, a village close to the fossil discovery site. The new fossils significantly expand the geographic, stratigraphic, environmental, and taphonomic distribution of some key Ediacara elements. Their occurrence in marine limestone of the Dengying Formation also suggests that these Ediacara taxa were not lichens living on land. Instead, they were marine organisms living a subaqueous life. Whether they are animals, animal precursors, or distant relatives of animals is still unknown. This research was supported by Chinese Ministry of Science and Technology, National Natural Science Foundation of China, Chinese Academy of Sciences, and U.S. National Science Foundation. Related information of this paper: Zhe Chen, Chuanming Zhou, Shuhai Xiao, Wei Wang, Chengguo Guan, Hong Hua, Xunlai Yuan, 2014, New Ediacara fossils preserved in marine limestone and their ecological implications. Scientific Reports, 4: 4180. DOI: 10.1038/srep04180
Ediacara fossils from Dengying Formation in the Yangtze Gorges area
Palaeoscolecdians are common worm fossils from Cambrian and Ordovician. Most scientists believe palaeoscolecdian worms can be assigned within the phylum Priapulida. Most research on palaeoscolecdians focus on taxonomy but their lifestyle were poorly-known. Some authors suggested an epifaunal lifestyle for these worms but others believe they are in faunal animals. However, the burrowing evidence is poorly-known to date except limited information from the Chengjiang fauna. Professor HUANG Diying from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences first suggested a burrow dwelling behavior of palaeoscolecdians in his Ph. D thesis since 2005. Some authors suggested a similar behaviour of Maotianshania cylindrical from the Chengjiang fauna in the later publication. After carefully re-examination on the type material, the previous so-called Maotianshania cylindrical are in fact Cricocosmia jinningensis and Mafangscolex sinensis. These three forms are the most abundant worms in the Chengjiang fauna but displayed different distributions. The present study indicates different morphology of burrows on Cricocosmia jinningensis and Mafangscolex sinensis on the basis of numerous specimens from various fossil localities. The potential mode of construction and taphonomy is also supposed. A similar burrow dwelling behavior is still present in modern priapulid worms namely Maccabeus. In additional, the locomotion of Cricocosmia jinningensis and Mafangscolex sinensis are also suggested. This project was supported by Chinese Academy of Sciences, National Basic Research Program of China and the National Natural Science Foundation of China. The research results have been published in Palaeogeography, Palaeoclimatology, Palaeoecology (HUANG Diying, CHEN Junyuan, ZHU Maoyan, ZHAO Fangchen, 2013: The burrow dwelling behavior and locomotion of palaeoscolecidian worms: New fossil evidence from the Cambrian Chengjiang fauna. Palaeogeography, Palaeoclimatology, Palaeoecology 398: 154-164).
Following the extinctions caused by the end-Ordovician (Hirnantian) glaciations, the world gradually returned to warmer climates, together with rising eustatic sea levels. As a result of those changes, benthic faunas steadily increased in diversity through the Early Silurian (Llandovery Series),and of those faunas, brachiopods are the most abundant. Recently, Professor RONG Jiayu from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Professor Robin Cocks from Natural History Museum, London, UK reviewed Silurian brachiopods of Middle Llandovery (Aeronian) ages. More than 200 genera are identified, compared with 109 in the preceding Early Llandovery (Rhuddanian), indicating a recovery-radiation interval after the end-Ordovician mass extinction. The chief regions in which they are found are the continents of South China, Avalonia-Baltica, Laurentia and Siberia, which were all at tropical latitudes with the exception of Avalonia. In addition, the very large super terrane of Gondwana, although with patchy brachiopod distribution, included temperate faunas, as well as subtropical faunas (in Iran and Afghanistan). Aeronian brachiopods greatly increased in diversity, with dominance of four major groups: orthides and strophomenides(which had flourished previously in the Rhuddanian), pentamerides and atrypides (which became dominant in the Aeronian), and many newly evolved taxa, and occupied deeper water and wider ecological niches (level bottom and reef) than those in the Rhuddanian. Each of the continents has some endemic genera, but there is agreater proportion of them in South China, where some groups (such as the pentamerides and atrypides) are more diverse and others, such as the orthides, are much less common than elsewhere. Affinity indices (AI) show that two megaunits can be recognized: South China and Avalonia-Baltica-Laurentia (ABL); Siberia seems to have been loosely connected with ABL and even more loosely to South China presumably because of its geographical separation in the Northern Hemisphere. The separation of South China from the other megaunits is further supported by cluster analysis. The research results have been published in Lethaia ( RONG Jiayu, Cocks L.R.M. 2014: Global diversity and endemism in Early Silurian (Aeronian) brachiopods. Lethaia, Vol. 47, pp. 77–106.)
Global palaeogeography in the Early Silurian at about 440 Ma, with the names of thecontinents discussed. WNEC andWSEC are ‘Western North Equatorial Currents’ and ‘Western South Equatorial Currents’.
The Kwangsian Orogeny was first proposed by Prof. Ting V K (Ding Wenjiang) in 1929. It originated along the southeast coast of China and stepwise developed in a northwestern direction. Based on a precise biostratigraphic study, two stages of the Kwangsian Orogeny were recognized: a long, locally varying uplift from the Late Ordovician to the early Silurian, and a finally tectonic movement near the Silurian and Devonian transition. The Kwangsian uplift event shows a stepwise delay northwestwards from the southeastern coast area in the Nemagraptus gracilis Biozone to the south side of the Xuefeng Mountains in or later than the Cystograptus vesiculosus Biozone to the Coronograptus cyphus Biozone. In the south of the Yangtze Platform, the Yichang Uplift was driven by the Kwangsian Orogeny forming a diachronous stratigraphical break through Rhuddanian and Aeronian. The research article by Professor CHEN Xu from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues was published as a cover paper of the Science China: Earth Sciences. Detailed information: CHEN Xu, FAN Junxuan, CHEN Qing, TANG Lan, HOU Xudong. 2014. Toward a stepwise Kwangsian Orogeny. Science China: Earth Sciences, 57(3): 379-387, doi: 10.1007/s11430-013-4815-y
Ordovician and Silurian correlation from the southeastern coast of China to the Yangtze region through the Xuefeng-Jiuling Mountains
Northwestward stepwise uplift of the Kwangsian Orogeny from the southeastern coast of China to the Yangtze region through the Xuefeng-Jiuling Mountains
The family Osmundaceae is significant among ferns due to its extensive fossil record with more than 200 species. Among them, over 80 species are recognized based on permineralized rhizome specimens. Compared to fossil foliages, the permineralized materials are crucial for studying the classification, phylogeny and evolution of the Osmundaceae because they bear more anatomical and phylogenetic information. However, the anatomical diversity and phytogeographic history of the fossil Osmundaceae are not well understood. A new fossil species, Ashicaulis plumites has been recognized from the Middle Jurassic in western Liaoning, NE China by Professor WANG Yongdong from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his research team. This result has been published in a recent issue of Springer journal Journal of Plant Research.
This new species is characterized by a specialized petiolar structure yielding a sclerenchyma mass with a distinctive outward protuberance in the petiolar vascular bundle concavity, which distinguishes the present new species from other Ashicaulis species. Such a protuberance has been only observed in Osmunda pluma Miller from the Palaeocene of North America, and represents a distinct type for sclerenchymatous tissue in the osmundaceous vascular bundle concavity. The specialized structure of this new fossil species enriches anatomical diversity of permineralized osmundaceous ferns, indicating that the family Osmundaceae might have experienced a remarkable diversification during the Middle Jurassic in NE China.
Detailed information: Tian, N., Wang, Y.D.*, Philippe, M., Zhang, W., Jiang, Z.K., Li L.Q., 2014. A specialized new species of Ashicaulis (Osmundaceae, Filicales) from the Jurassic of Liaoning, NE China. Journal of Plant Research, 127: 209-219 (* corresponding author).
The anatomical characteristics of Ashicaulis plumites (sp. nov.)
The specialized petiolar structure of Ashicaulis plumites (sp. nov.)
Variation of sclerenchyma mass of Ashicaulis plumites (sp. nov.)
Insects are the most diverse group of animals on Earth today, and also have an extensive fossil record from the Carboniferous to recent. Interpretation of fossil insects and reconstruction of their paleodiversity must consider the taphonomic processes involved because decay influences the preserved morphology, which strongly affects diversity estimates. Furthermore, the taphonomy of insects is essential to interpreting the paleoecology and paleoenvironment. Various intrinsic as well as extrinsic factors significantly control the preservation of insects. Few studies have presented a quantitative comparison of biostratinomic patterns in different groups. Associate Professor WANG Bo and Professor ZHANG Haichun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues systematically investigated the preservation of 277 specimens of Palaeontinidae and 113 of Tettigarctidae, two hemipterous families from the Jurassic Daohugou beds lacustrine Konservat-Lagerst？tte. They carried out quantitative analyses of their size and taphonomic characters, including body orientation, articulation, and preservational quality, and also performed a preliminary experiment to understand the floating and decay process of cicadas. Their statistical analyses reveal significant differences in both body orientation and preservational quality between the two families. Palaeontinidae experienced longer flotation time (mostly over one month) before settling through the water column due to their high SM index (wing surface/body mass ratio) and unfolded wings, increasing the opportunity to decompose on the water surface and resulting in the dorsoventral preservational position with lower preservational quality. In contrast, Tettigarctidae have a comparatively low SM index and overlapping wings, so that their drifting period on the water surface might have been short (mostly within 2 weeks), leading to the lateral preservation position with higher preservational quality. Their taphonomic variations were controlled by different SM indices and wing folding modes. The biological factors recognized may control taphonomic patterns in other fossil insects with similar body forms and wing folding patterns. Insects sometimes possess very different ecological traits and morphological characteristics. The results suggest that these differences may determine their preservation patterns by controlling their taphonomic processes, such as transport distance, floating time, and decay rate. Different taxonomic groups of insects may have different taphonomic processes, leading to contrasting preservational patterns and taphonomic bias. The taphonomic variability of insects at family level should be noted in future taphonomic studies. In addition, the wing folding behavior and subsequent different modality of fossilization between these two groups also introduced another difficulty during the taxonomic study, i.e. important wing venation characters are mainly obscured in the Tettigarctidae. The taphonomic variability should, therefore, betaken into account in future studies of paleodiversity estimation and paleoecological reconstruction of fossil insects. Related information of this paper: Wang Bo, Zhang Haichun, Jarzembowski E.A., Fang Yan, Zheng Daran (2013) Taphonomic variability of fossil insects: a biostratinomic study of Palaeontinidae and Tettigarctidae (Insecta: Hemiptera) from the Jurassic Daohugou Lagerst？tte. PALAIOS, 28: 233–242.
Professor YIN Leiming from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues recently made a new progress in the search for Cambrian ‘Cryptospore-like’ microfossils which has been selected as the cover of the SCIENCE CHINA Earth Sciences. Abundant specimens of cryptospore-like microfossils, including dyads, tetrads and monads, have been collected by palynological maceration from rock sample of the “Middle” Cambrian Log Cabin Member of the Pioche Shale in eastern Nevada, USA. Some specimens preserved in situ were observed by using SEM. Compared with organic-walled microfossils obtained from the Cambrian Kaili Formation in eastern Guizhou Province, China, some specimens of leiosphers may be inferred to be similar cryptospore-like microfossils. The new fossil record would be the oldest known specimens of cryptospore-like microfossils during the Cambrian Period. The Cambrian cryptospore-like microfossils might have originated from quite shallow water plant sporoderm forms. Although the Cambrian cryptospore-like microfossils have been recovered with a primitive spore wall structure as “protoembryophytes”, their phylobiology and living habits still require additional fossil discoveries to confirm their paleoecology and phylogeny. Related information of this paper: YIN LeiMing, ZHAO YuanLong, BIAN LiZeng, PENG Jin, 2013, Comparison between cryptospores from the Cambrian Log Cabin Member, Pioche Shale, Nevada, USA and similar specimens from the Cambrian Kaili Formation, Guizhou, China. SCIENCE CHINA Earth Sciences, 2013, 56(5): 703-709
