Recently, the famous international geological journal Palaeogeography, Palaeoclimatology, Palaeoecology (commonly referred to as "Palaeo 3") published a new special issue on the topic of Mesozoic and Cenozoic evolution of eastern Tethys co-edited by Prof Li Jianguo and Prof. Sha Jingeng in the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, and their international cooperation team (volume 515, 2019). Since the 1960s when the theory of plate tectonics became established, the Tethys region has attracted the attention of many geologists because it has experienced a complex evolution involving numerous continental fragments drifting in several stages from the Gondwanan margin in the Southern Hemisphere northward to amalgamate with Eurasia in the Northern Hemisphere. This process and the subsequent orogenies caused great changes to the regional or even global topography and environments, which researchers now realize had important impact on climate and biotas. The vast literature on the evolution of the Tethys Ocean highlights several critical scientific issues that require further investigation. These include especially: (1) what was the extent of the Tethys and its surrounding landmasses at the time that Pangea began to break up?; (2) when and how did the Cimmeride terranes rift from Gondwana and collide with proto-Eurasia?; (3) what was the motion history of the Indian plate during its northward journey, and when and where did it collide with Eurasia?; (4) when did the Neo-Tethys come into being and subsequently close up?; (5) what was the driving force behind continental fragmentation that gave rise to the Neo-Tethys?; (6) what processes were involved in the uplift of the Qinghai-Xizang Plateau, and what was the chronology of uplift events?; (7) what were the impacts of these events on Earth’s climate and biotas? (Fig. 1). The answers to each question in above are complex and require a large number of facts or data from multiple regions and disciplines. So far, the data and findings revealed and accumulated by scientists are still very scarce, restricting our progress in the study of Tethys tectonics and biological evolution. The newly published special issue reports the latest research results of scientists from multiple countries in magmatic petrology, geochemistry, palaeontology and sedimentology from the eastern Tethys. A total of 13 research papers and one reviewing paper as preface are contained. These papers cover a multitude of issues relating to the evolution of the Tethys, such as the timing of initiation of the Neo-Tethys, the properties of the Bangong-Nujiang Tethys, the rifting process of the Indian plate, palaeoenvironmental events during Tethyan evolution, the impact on terrestrial ecosystems of closure of the Tethys and uplift of the Qinghai-Xizang Plateau. These advances provide insights into and will stimulate further research on the evolution of the eastern Tethys. This SI is a joint product of years of collaboration and efforts by scientists from various countries and is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB03010103, XDB26000000 and XDA20070202), the National Natural Science Foundation of China (41872004), and UNESCO -IUGS project IGCP 632. Special issue information: Li, Jianguo, Sha, Jingeng, McLoughlin, Stephen, Wang, Xiaoming, eds., 2019. Palaeogeographic, palaeoclimatic and palaeoecologic evolution of eastern Tethys during the Mesozoic and Cenozoic. Palaeogeography, Palaeoclimatology, Palaeoecology 515. A summary of key events in the evolution of Tethys as studied by previous researchers and authors in this issue
Our understanding of the early evolutionary history of sponges is largely impeded by the scarcity of early sponge fossil record, In spite of the purported sponge fossil from the Ediacaran Weng’an Biota, the earliest sponge spicules were found in the Protohertzina anabarica zone of about 535 Ma old. However, the taxonomically informative sponge fossils, which should preserve articulated skeletal frames, were only known from the shale Lagerstatten started from the terminal Cambrian Stage 2. Examples include the black shale of the Niutitang and Hetang Formations, the Chengjiang Biota, the Sirius Passet Biota, the Kaili Biota, the Burgess Shale, etc..A recent study of Dr. LUO Cui from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Prof. Dr. Joachim REITNER from the University of Goettingen, published online on Feb 28, 2019 in PalZ, revealed in situ, three-dimensionally preserved sponge fossils from the Terreneuvian phosphorites from Hunan, China.These phosphorites underlying the Ni-Mo layer of the Niutitang Formation is inferred to be no younger than the Cambrian Age 2 based on the previous radiometric dating and biostratigraphic studies of correlative strata. In situ preserved sponge fossils are distributed as nodular bodies in the authigenic carbonaceous cherty phosphorites which exhibit laminated and clotted cryptocrystalline fabrics. Some of the fossils are completely embedded in the honey-colored cryptocrystalline phosphates, while most of them are preserved in the way that the spicules are immediately encrusted by isopachous cryptocrystalline phosphate, with the remaining interspace filled by later phosphate or siliceous cements, and/or pyrobitumen.The morphology of two fossils was described as examples:One of them, preserved in the former state mentioned above, is thick-walled, consisting of similar triaxons of three different size hierarchies. The small spicules in the 2nd and 3rd hierarchies are randomly distributed. The other one, preserved in the latter state mentioned above, was investigated using grinding tomography to reconstruct its 3D architecture in a 6mm×5mm×1mm space. This fossil is mainly composed of pentactins, few hexactins, diactins, and other forms. Some pentactins are distributed with the paratangential rays more or less parallel to the surface of the nodular body, a way similar to hypodermalia.Other spicules are generally irregularly arranged, but sometimes also exhibit a perpendicular arrangement with respect to contacting spicules and to other spicules in the 3D space. These morphological types were previously unknown from the lower-middle Cambrian shale Lagerstatten, although they appear to be in accordance with the hexactinellid stem groups hypothesized by some researchers (e.g. Mehl, 1996; Dohrmann et al., 2008).In addition, various forms of disarticulated sponge spicules were also observed in these lower Cambrian phosphorites, some of which showing demosponge-specific features or combined features of hexactinellids and demosponges, indicating still unexplored sponge biodiversity in this particular age and taphonomic window.This study was financially supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, the CAS Key Laboratory of Economic Stratigraphy and Palaeogeography (NIGPAS), and the German Excellence Initiative (Goettingen Courant Center).Reference: Luo, Cui, and Joachim Reitner*. 2019. Three-dimensionally preserved stem-group hexactinellid sponge fossils from lower Cambrian (Stage 2) phosphorites of China. PalZ. doi:10.1007/s12542-018-00441-y. Petrology of the nodular phosphorites and the preservation of sponge fossils. Projection of the 3D architecture of the spicules in a nodular body in a 2D surface.
Recent advances in Devonian palaeoecosystems and palaeoenvironments of South China have been published in a special issue of “Palaeobiodiversity and Palaeoenivronments”. The eight contributions in this volume cover different fossil groups, including tentaculitids, brachiopods, conodonts, tabulate corals, ostracods, and ammonoids, meant to advance the understanding of Devonian palaeoecosystems and palaeoenvironments of South China, with a special emphasis on interplay between different fossil groups and environments during this critical period of Earth history.The issue was co-edited by Drs. Wenkun Qie and Kun Liang from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Dr. Peter Konigshof from the Senckenberg Forschungsinstitut und Naturmuseum Frankfurt.The Devonian (419.2–358.9 Ma) was a critical period for the evolution of life in both terrestrial and marine ecosystems. It witnessed the appearances of first forest and amphibian on land, the largest metazoan reef ecosystem in Earth history, and two greatest biocrisises of the Phanerozoic (the Frasnian-Famennian and Hangenberg mass extinctions).The colonization of land by vascular plants caused major changes with respect to processes in the geo-, hydro-, and atmosphere. Continental weathering became strongly influenced by chemical processes, and thereby causing changes in riverine nutrient flux, and atmosphere CO2 concentration dropped abruptly to near modern level, all of which exert major impacts on the marine ecosystem. As many as global events, characterized by eustatic sea-level changes, anoxic/hypoxic events, and/or biological extinction/turnovers took place during the Devonian, demonstrating complex interactions between the Earth’s biotic, climatic, and environmental systems. Understanding the different fossil groups and the evolution of Devonian marine ecosystem at global or regional scale would help to gain important insights for the interplay between life and environment in deep time. South China is the most important area for the study of the Devonian system in China, where all the stratotype sections for the Chinese regional stages were established in shallow water facies of this region. Following the Kwangsian Orogeny, a transgression occurred in central Guangxi during the Lochkovian, and each sequences in South China starts with some siliciclastic sediment overlying a discontinuity surface. With intensified rifting, major differentiation of lithofacies and biofacies took place in the Emsian and Givetian stages, and the deposition of extensive carbonate platform was separated by deep-water interplatform basins. As a result, there are numerous well-preserved Devonian stratigraphic successions recording a variety of lithofacies and biofacies in South China, providing excellent materials to investigate the biotic and environmental events and their possible causes and effects.This special issue includes 1 editorial and 8 scientific papers, details are as following:1. Qie, W. K., Liang, K., Konigshof, P. 2019. Devonian palaeoecosystems and palaeoenvironments of South China. Palaeobiodiversity and Palaeoenvironments. 99:1–5.2. Wei, F., Zong, R. & Gong, Y.M. (2019). Tentaculitids and their evolutionary significance in the Early Devonian Dashatian section, South China. Palaeobiodiversity and Palaeoenvironments, 99(1).3. Guo, W., Nie, T., & Sun, Y.L. (2019). New data on biostratigraphy of the lower Devonian “Spirifer” tonkinensis Brachiopod fauna in South China and adjacent region. Palaeobiodiversity and Palaeoenvironments, 99(1).4. Lu, J.F., Valenzuela-Ríos, J.I., Wang, C., Liao, J.-C. & Wang, Y. (2019). Emsian (Lower Devonian) conodonts from the Lufengshan section (Guangxi, South China). Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0325-4 5. Zhang, M. & Ma, X. (2019). Origination and diversification of Devonian ambocoelioid brachiopods in South China. Palaeobiodiversity and Palaeoenvironments. Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0333-4 6. Qiao, L. & Qie, W.K. (2019). Palaeobiogeographic dynamics of brachiopod faunas during the Frasnian-Famennian biotic crisis in South China. Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0336-17. Liang, K., Qie, W., Pan, L. & Yin, B. (2019). Morphometrics and palaeoecology of syringoporoid tabulate corals from the upper Famennian (Devonian) Etoucun Formation, Huilong, South China. Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0363-y8. Song, J.J. & Gong, Y.M. (2019). Ostracods from the Devonian-Carboniferous transition in Dushan of Guizhou, South China. Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0322-79. Zhang, M., Becker, R.T., Ma, X., Zhang, Y. & Zong, P. (2019). Hangenberg Black Shale with cymaclymeniid ammonoids in the terminal Devonian of South China. Palaeobiodiversity and Palaeoenvironments. Palaeobiodiversity and Palaeoenvironments, 99(1). https://doi.org/10.1007/s12549-018-0348-xThis special issue is partly supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB26000000) and NSFC grant (41772004).
The end-Ordovician mass extinction (EOME) was the first of the “Big Five” extinctions of the Phanerozoic. It is widely interpreted as consisting of two pulses associated with the onset and demise of the Gondwana glaciation, respectively, with the second pulse eradicating the distinctive, glacially related Hirnantian benthic biota (HBB). This two-pulse model has become a widely accepted paradigm within which tempo, magnitude, pattern and dynamics of the EOME and the subsequent recovery have been variously interpreted.Recent investigations in South China, however, indicate an erroneous temporal and causal link between the “HBB” and the Gondwanan glaciation, which, if confirmed globally, will hence underpin a critical reevaluation of the tempo and nature of the EOME.To further elucidate this key issue, Dr. WANG Guangxu from the Nanjing Institute of Geology and Palaeontology of Chinese Academy of Sciences and his colleagues made a global review of occurrence data of latest Ordovician benthic marine organisms, which reveals that virtually all warm-water benthic assemblages previously assigned to the HBB comprise two distinct and clearly postglacial faunas, both younger (middle and late Hirnantian, respectively) than the cool-water Hirnantia fauna (latest Katian to early Hirnantian).The newly recognised three Transitional Benthic Faunas (i.e., TBFs 1–3) can be closely tied to graptolite, conodont, and chitinozoan biozonations, the Hirnantian Isotope Carbon Excursion (HICE), and the glaciation, thereby providing an integrated, much higher resolution timescale for understanding the tempo and nature of the EOME.At such a finer resolution, these authors also postulate a more profound impact of the first pulse of the EOME than hitherto envisaged, as evidenced by opportunistic expansion of the Hirnantia fauna globally and the complete absence of metazoan reefs in its immediate aftermath. They also argue, based on high-quality data from well-documented benthic groups in South China (i.e., brachiopods, tabulate and rugose corals, trilobites, and sponges), that the magnitude of the second pulse of the EOME caused by the deglaciation has been overestimated because the two postglacial faunas (i.e., TBFs 2–3) were part of a subsequent recovery phase of marine ecosystems rather than contributing to biodiversity decline. Thus, they reinterpret the EOME as a single-pulse, rapid event that was followed by a prolonged initial recovery intermittently impeded by climatic shocks through the Hirnantian, prior to the onset of a progressive reestablishment of marine ecosystems during the early Silurian (Rhuddanian and Aeronian) associated with an overall amelioration of climatic conditions.Reference: Wang, G.X., Zhan, R.B. and Percival, I.G., 2019. The end-Ordovician mass extinction: A single-pulse event? Earth-Science Reviews, 192: 15–33. Models of latitudinal patterns of TBFs 1–3 through the Hirnantian. A refined integrated Hirnantian stratigraphic framework, against which biotic and environmental changes across the EOME are also shown.
During the Ordovician, most Chinese continental blocks were located near the tropical area around the Gondwanan supercontinent, containing South and North China, Tarim, Himalaya, Lhasa and Sibumasu (Baoshan). Their paleogeographic locations and movements have always been research hotspots. Recently, Dr. FANG Xiang and Prof. ZHANG Yuandong from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, and Prof. Clive Burrett from Mahasarakham University, Thailand, conducted a quantitative statistical analysis of Middle to Late Ordovician cephalopods from the northeastern peri-Gondwana region, in order to reconstruct palaeobiogeographic distributions and their dynamic variation which indicate palaeoplate movements during the Middle to Late Ordovician Cephalopods have a very strong swimming ability. But because of the septal strength index, cephalopods would implode if they got deeper than their limited depth. Based on studies on living Nautilus, cephalopods need to rest on the sea floor after swimming for a long time. We can use this to assess the palaeogeographic provincialism of cephalopods and then speculate on the relative dynamic locations of Gondwana and the Asian blocks. In this study, based on published literature and the latest palaeontological researches on South China, several statistical methods, including cluster analysis, nonmetric multidimensional scaling and network analysis, of Middle to Late Ordovician cephalopod occurrences in the northeastern peri-Gondwanan region were conducted. For the Middle Ordovician, three biogeographic provinces may be recognized in the northeastern peri-Gondwana region: the Australia, the North China–Tibet–Sibumasu (NTS), and the South China–Altun (SA) provinces. However, this biogeographic pattern changed significantly in the Late Ordovician, when the cephalopods in the Tibetan and Sibumasu terranes changed markedly to show greater similarity to South China, and form the South China–Tarim–Tibet–Sibumasu (STTS) Province. The study shows that different composition of these two provinces and different types of cephalopods indicating that during the Middle Ordovician, the NTS province should be located in the tropical zones, and SA province in a slightly higher latitude region. During the Late Ordovician, South China was drifting slowly northwards, closer to Australia, meanwhile North China was drifting gradually away from northeastern peri-Gondwana. This dynamic variation of cephalopod provincialism for Middle and Late Ordovician cephalopods was related to alterations of palaeolatitude and the changing locations of the palaeoplates during the Middle and Late Ordovician. This study was financially supported by the National Natural Science Foundation of China, Ministry of Science and Technology of China and Chinese Academy of Sciences. This study is a contribution to IGCP projects 653 and 668. Reference: Xiang Fang*, Clive Burrett, Wenjie Li, Yunbai Zhang, Yuandong Zhang, Tingen Chen, Xuejin Wu, Dynamic variation of Middle to Late Ordovician cephalopod provincialism in the northeastern peri-Gondwana region and its implications. Palaeogeography, Palaeoclimatology, Palaeoecology, 521: 127-137. https://doi.org/10.1016/j.palaeo.2019.02.015 Cluster analysis (upper left), nonmetric multidimensional scaling (lower left) and network analysis (right) recognize the palaeobiogeographic provinces in Middle and Late Ordovician Published typical cephalopods from NTS Province in the Middle Ordovician (left) and published typical cephalopods from STTS Province in the Late Ordovician (right)
Recently, an international team led by Prof. ZHOU Chuanming from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences reported two new high-precision U-Pb zircon dating data from two layers above the Cryogenian Sturtian and Marinoan in South China, which provides evidence for the globally synchronous and rapid termination of Cryogenian glaciations. The result and related analysis were published in Geology.Cryogenian Sturtian and Marinoan glaciations represent the most severe paleoclimatic events in Earth history. The global distribution of presumably synchronous Cryogenian glacial deposits is one of the key observations that stimulated the initial formulation of the Snowball Earth Hypothesis or SEH. The formalization of the SEH leads to explicit predictions about the global synchroneity and duration of Cryogenian Snowball Earth glaciations. Specifically, the SEH predicts a globally synchronous and rapid termination of Cryogenian glaciations on the time scale of 103–104 years.Wherever the deglaciation began is difficult to define in the sedimentary record, the sharp transition from glacial diamictite to postglacial cap dolostone, which represents a landmark event during deglaciation, can be used to demarcate the final stage of deglaciation. A direct test of rapid and globally synchronous deglaciation requires high-resolution (better than ± 1.0 Ma) geochronological data to tightly bracket the transition from diamictite to cap dolostone in multiple paleocontinents or basins.Currently available geochronological data are consistent with the occurrence of two global glaciations in the Cryogenian Period (~ 720？635 Ma), i.e., the Sturtian and Marinoan glaciations. However, high-precision radiometric dates are few and do not have a sufficient paleogeographic and stratigraphic coverage to allow a positive test of global synchroneity and rapidity as predicted by the SEH. For example, on the basis of currently available data, the Marinoan deglaciation in Australia, Namibia, and South China are constrained to be <636.41 ± 0.45 Ma, <635.21 ± 0.59 Ma, and between 636.3 ± 4.9 Ma and 635.23 ± 0.57 Ma, respectively. These ages, while consistent with global synchroneity, are not sufficient to determine synchronous deglaciation among these three paleocontinents. Thus, to positively determine global synchroneity and rapidity of Cryogenian deglaciation events, we need more high-precision radiometric dates from glaciogenic diamictite and postglacial cap dolostone to tightly bracket the final deglaciation on each paleocontinent. To this end, Prof. ZHOU Chuanming and colleagues from the University of California at Davis and Virginia Tech, reported two new high-precision U-Pb zircon CA-ID-TIMS of 658.80 ± 0.50 Ma and 634.57 ± 0.88 Ma from tuffaceous layers that occur, respectively, within the cap dolostone atop the Tiesi’ao diamictite (Sturtian age) and at the topmost Nantuo diamictite (Marinoan age) in South China. The 658.80 ± 0.50 Ma age represents a high-precision minimum age constraint on the termination of the Sturtian-age glaciation. The 634.57 ± 0.88 Ma age and a previously published age of 635.23 ± 0.57 Ma from the topmost cap dolostone are indistinguishable within uncertainty, and together they provide tight constraints on the termination of the Marinoan glaciation in South China at ca. 635 Ma and directly bracket the duration of the cap dolostone to be <106 yrs. The new data support the rapid termination of the Marinoan glaciation in South China and are consistent with global synchroneity of Cryogenian deglaciation events. To positively test whether the same is true on other continents and for the Sturtian deglaciation requires additional high-resolution ages on each paleocontinent.Reference: Chuanming Zhou, M. H. Huyskens, Xianguo Lang, Shuhai Xiao, Qing-Zhu Yin, 2019. Calibrating the terminations of Cryogenian global glaciations. Geology, 47: 251-254. https:// doi .org /10 .1130 /G45719.1 206Pb/238U ages of individual zircons for samples 17LSJ-17 and ES-1 Compilations of radiometric ages and their relationship with the supposed Sturtian and Marinoan glaciations on different continents.
The hyperdiverse rove beetle genus Stenus (Steninae) has one of the most specialized prey-capture structures known from extant arthropods. They use a ‘tongue’-like apparatus formed by a protrusible labium with terminal sticky cushions and a haemolymph pressure to catch fast-fleeing prey. Fossils with an exposed apparatus are exceedingly rare. Mesozoic stenines are therefore significant for elucidating the early evolution of the group. Recently, an international team led by Dr. CAI Chenyang, from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences, reported two species of the extinct stenine genus Festenus from mid-Cretaceous Burmese amber, some 99 million years ago, which provides important information about the origin and early evolution of both the novel predatory structure and of the beetle subfamily. Steninae include three extant genera: the widespread Stenus, the Holarctic Dianous, and a new genus from Australia. Living in various microhabitats, extant Stenus species prey on fast-fleeing springtails and other small animals. The species of Dianous lack such a protrusible labium. Dr. Cai and his colleagues examined over 120 individuals of Steninae, and found an exposed prey-capture apparatus in only two specimens. The ‘tongue’-like apparatus displays a generalized form, just as that in extant species such as Stenus comma. Therefore, like modern Stenus species, these fossil stenine rove beetles were likely able to catch small-sized animals such as springtails using their sticky apparatus. The discovery of direct evidence of a protrusible prey-capture apparatus in one of the earliest known stenine beetles from the Cretaceous illuminates their early evolution and confirms an ancient origin for their derived predatory behavior. Molecular phylogenetic studies of selected species of Stenus and Dianous indicated an origin of Dianous within Stenus, suggesting a secondary loss of the harpoon apparatus. The presence of a protrusible prey-capture apparatus has been considered the most prominent apomorphic character for Stenus, but this assumption is rejected the new disveorey of these Mesozoic Steninae with specialized prey-capture apparatus Reference: Chenyang Cai*, D.J. Clarke, Ziwei Yin, Yanzhe Fu, Diying Huang, 2019. A specialized prey-capture apparatus in mid-Cretaceous rove beetles. Current Biology. DOI: 10.1016/j.cub.2019.01.002. Specialized prey-capture apparatus in an extant Stenus species. Specialized prey-capture apparatus in mid-Cretaceous stenine rove beetles.
Anchiornis, one of the earliest feathered dinosaurs ever discovered, was found to have the ability to fly. However, could it fly like birds today? A new study published in the Proceedings of the National Academy of Sciences (PNAS) by researchers from China and the U.S. says no. The flight feathers of modern birds are mainly composed of β-keratin, which gives them special biomechanical properties (such as flexibility, elasticity and strength) to meet the needs of flight. Dr. PAN Yanhong from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and her colleagues used electron microscopy and chemical analyses to compare flight feathers of Anchiornis with those of a chicken and four other feathered dinosaur and fossil birds. They found that Anchiornis feathers were predominated by thicker α-keratins rather than thinner β-keratins, and lacked the biomechanical properties needed for flight, although they did contain some of the necessary molecular structures as indicated by the presence of feather β-keratins. On the other hand, Pan and colleagues also showed that the flight feathers of Chinese Mesozoic birds such as Eoconfuciusornis and Yanornis, as well as a Cenozoic bird, were mainly composed of β-keratins, as in modern birds. The findings suggest that even though Anchiornis feathers were not suitable for powerful flight, their molecular composition may signify an intermediate stage in the evolution of avian flight feathers. Researchers from NIGPAS, the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Linyi University, North Carolina State University, and South Carolina State University participated in the study. The study was supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Yanhong Pan, Wenxia Zheng, Roger H. Sawyer et al., 2019. The molecular evolution of feathers with direct evidence from fossils. PNAS. DOI: http://doi.org/10.1073/pnas.1815703116. The Anchiornis (STM0-214) specimen studied in this work, collected from Jianchang, western Liaoning, location of samples is marked by red box. A TEM image of the fossilized feather from the Anchiornis specimen, showing the thick filaments composed of α-keratins dominated at the ultrastructural level. Time-scaled evolution of molecular composition and ultrastructure of feathers within a Mesozoic avian and non-avian phylogeny. Filled stars showing the distribution of tested fossil feathers and related integumentary tissues used in this study.
The Fotan Group from Zhangpu of Fujian yielded abundant plant megafossil and amber, generating a typical Miocene tropical rainforest ecosystem of China. The plant fossils are preserved in diatomite and mudstone, while the amber occurs within coal seams and diatomite that directly underlie the layer hosting plant flora. Determining the age of Fotan fossil horizons can help date the Miocene tropical rainforest in China and constrain its long-term history. Recently, Dr. ZHENG Daran and Associate Professor SHI Gongle from the ‘Modern terrestrial ecosystem origin and early evolution’ group at Nanjing institute of Geology and Palaeontology of Chinese Academy of Sciences, cooperating with the researchers from the University of Hong Kong and Columbia University, pioneered this age-determining research and provided a robust 40Ar/39Ar age for the Fotan biota based on the basalt samples from Maping and Wuling of Zhangpu, Fujian Province. For the sample from Maping, incremental heating analysis of groundmass yielded a plateau age of 14.5 ± 1.5 Ma (MSWD = 0.65). Data from the step-heating analysis were plotted on an inverse isochron isotope correlation diagram (36Ar/40Ar vs. 39Ar/40Ar). The isochron age of 15.2 ± 2.0 Ma (MSWD = 1.2) shows well agreement with the plateau age including its error term. For the sample from Wuling, incremental heating analysis of groundmass yielded a well-defined plateau age of 14.7 ± 0.4 Ma (MSWD = 0.28). The isochron age of 14.7 ± 0.4 Ma (MSWD = 0.96) is identical with the plateau age. The 302 ± 2 40Ar/36Ar intercept from the inverse isochron diagram resembles atmospheric values (i.e., 295.5 or 298.56). Although the age results for both samples are indistinguishable at the 2σ level, we interpret the more precise 14.7 ± 0.4 Ma ages as the upper limit of the depositional age of the Fotan fossils. This age constrains interpretations of the early evolution of tropical rainforest ecosystems in Asia, and laid foundation for the systematic study of Zhangpu amber biota. This research was recently published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, and supported by the National Natural Science Foundation of China and RGC General Research Fund of Hong Kong. Reference: Zheng, D., Shi, G., Hemming, S.R., Zhang, H., Wang, W., Wang, B., Chang, S.-C.*, 2019. Age constraints on a Neogene tropical rainforest in China and its relation to the Middle Miocene Climatic Optimum. Palaeogeography, Palaeoclimatology, Palaeoecology, 518: 82–88. DOI: https://doi.org/10.1016/j.palaeo.2019.01.019. Photograph of a outcrop in Fotan, Zhangpu Stratigraphic column of Fotan Group in Zhnagpu 40Ar/39Ar age result
It is well-known that living fossils exhibit stasis over geologically long time scales. Examples are the panda and ginkgo. Now, two tiny beetles trapped in 99-million-year-old amber may join this group. Beetles are the most species-rich group of animals on our planet. Among four extant suborders of beetles, polyphaga is the largest and most diverse group. The origin and early evolutionary history of polyphagan beetles have been largely based on evidence from the derived and diverse ‘core polyphaga’, whereas little is known about the species-poor basal polyphagan lineages, which include Clambidae and four other extant families. Recently, an international team led by Dr. CAI Chenyang, from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences, reported two new and rare species of the extant family Clambidae from Burmese amber: Acalyptomerus thayerae Cai and Lawrence, 2019, and Sphaerothorax uenoi Cai and Lawrence, 2019. They are important for understanding the early evolution and biogeography of the family and even for polyphagan beetles. Clambidae is a small group of small-sized (usually 0.7–2.0 mm long) polyphagan beetles distributed worldwide, with approximately 150 described species grouped in five extant genera. Most clambid adults occur in decaying vegetation, leaf litter and rotten wood and occasionally fly at dusk. The two new species, represented by five well-preserved fossils, were discovered by Dr. CAI and colleagues from mid-Cretaceous Burmese amber. Both species are extremely morphologically close to their living counterparts, and can be placed in extant genera. Acalyptomerus thayerae (about 1.05–1.15 mm long) has a close affinity to A. herbertfranzi, a species currently occurring in Mesoamerica and northern South America. Sphaerothorax uenoi (about 0.71 mm long) is closely related to extant species of Sphaerothorax, which are usually collected in forests of Nothofagus in Australia, Chile and New Zealand. The discovery of two Cretaceous species from northern Myanmar indicates that both genera had lengthy evolutionary histories, originating at least by the earliest Cenomanian, and were probably more widespread than at present. Remarkable morphological similarities between fossil and living species suggest that both genera changed little over long periods of geological time, which is usually considered to be a feature of living fossils. The long-term persistence of similar mesic microhabitats such as leaf litter may account for the 99-million-year morphological stasis in Acalyptomerus and Sphaerothorax. Reference: Cai C*, Lawrence JF, Yamamoto S, Leschen RAB, Newton AF, Slipinski A, Yin Z, Huang D, Engel MS. 2019. Basal polyphagan beetles in mid-Cretaceous amber from Myanmar: biogeographic implications and long-term morphological stasis. Proc. R. Soc. B, 20182175. DOI:10.1098/rspb.2018.2175 Acalyptomerus thayerae from mid-Cretaceous Burmese amber (Image by NIGPAS) Sphaerothorax uenoi from mid-Cretaceous Burmese amber (Image by NIGPAS) Geographical distribution of Acalyptomerus thayerae and Sphaerothorax uenoi and their related extant counterparts (Image by NIGPAS)
