Silicified microfossils from the Doushantuo Formation at the Lujiayuanzi section Doushantuo-Pertatataka acritarchs (DPAs) are abundant and well preserved in the Ediacaran Doushantuo Formation in South China. Not only do they provide insights into the marine ecosystem immediately after a Neoproterozoic global glaciation, they also afford us an ideal tool for Ediacaran stratigraphic subdivision and correlation. However, previous reports of DPAs in South China are mostly from the Yangtze Gorges area in intra-shelf basin and from Weng’an in shelf margin environments, while data from localities in slope and basinal facies are lacking. In recent years, OUYANG Qing and colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences have carried out stratigraphic and microfossil investigations for an upper slope section of the Doushantuo Formation at Lujiayuanzi in northwestern Hunan Province, South China. Five DPA genera and eight species have been discovered from the Doushantuo Formation chert nodules, with the uppermost two DPA horizons occurring above a δ13C negative excursion that is correlated with the EN3/Shuram excursion based on integrated litho- and chemostratigraphic correlation. The new findings reveal a broader temporal and spatial distribution of DPAs in South China, and further support their biostratigraphic potential in the early？middle Ediacaran subdivision and correlation. Lithostratigraphic column, fossil occurrences, and chemostratigraphy of the Lujiayuanzi section This work was supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences (grant number XDB18000000), the National Natural Science Foundation of China (grant number 41672027), National Basic Research Program of China (grant number 2013CB835005), and the US National Science Foundation (EAR1528553). Article information: Ouyang, Q., Guan, C., Zhou, C.*, Xiao, S., 2017, Acanthomorphic acritarchs of the Doushantuo Formation from an upper slope section in northwestern Hunan Province, South China, with implications for early–middle Ediacaran biostratigraphy. Precambrian Research, 298: 512–529.
Lithology and chitinozoan stratigraphic ranges of the Middle–Upper Ordovician Miaopo Formation at Jieling, northern Yichang, western Hubei. As an extinct group of organic-walled, planktic microfossils, chitinozoan is characterized by its wide distribution and short temporal range of its species, which enables it to become an important tool in the stratigraphic correlation. The most significant chitinozoan acme appeared in the late Middle to early Late Ordovician in Baltica and North Gondwana. A relatively high diversity value also appeared during this time interval in Laurentia. However, chitinozoan biodiversity in the Yangtze Platform, as well as in China, was originally thought to be fairly low for this time interval in comparison with those of other major palaeoplates or terranes. And the chitinozoan biostratigraphic sequence for this time interval requires further work for regional and global correlations. During the last two years, Dr. LIANG Yan from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and her colleagues described and analyzed a diverse and abundant chitinozoan assemblage from the Middle–Upper Ordovician Miaopo Formation at Jieling, Yichang area of South China. Forty-three species of 16 genera were identified, which substantially increases the chitinozoan diversity of this particular time interval of the South China palaeoplate. Biostratigraphic subdivision and correlation of the Middle–Upper Ordovician in South China and Baltica. Several key chitinozoan species from North Gondwana and Baltica are reported for the first time in China. The chitinozoans of this formation have mixed North Gondwana and Baltica palaeogeographic affinities. The recognition of Laufeldochitina stentor and Armoricochitina granulifera guarantees a better biostratigraphic correlation between South China and Baltica. Most of the formation, except for its topmost part, is assigned to the L. stentor Biozone, which can be further subdivided into two subzones: the Cyathochitina megacalix sp. nov. Subzone (lower) and the A. granulifera Subzone (upper). Additionally, three new species are formally described, including C. megacalix sp. nov., Cyathochitina raricostata sp. nov. and Eisenackitina tenuis sp. nov. This research was funded by the National Natural Science Foundation of China, State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences. This paper is a contribution to the IGCP 653 (The Onset of the Great Ordovician Biodiversification Event). Article information: Yan Liang, Florentin Paris, Peng Tang. 2017. Middle–Late Ordovician chitinozoans from the Yichang area, South China. Review of Palaeobotany and Palynology 244, 26-42. Doi: 10.1016/j.revpalbo.2017.04.004.
Diagram showing the generic (diversity) and specimen (abundance) percentages of various major groups of late Hirnantian and early Rhuddanian brachiopods (theCathaysiorthis fauna), and late Katian brachiopods in the Jiangnan Region, Southeast China. Classification of extinction events and their severity is generally based on taxonomic counts. The ecological impacts of such events have been categorized and prioritized but rarely tested with empirical data. In a recent study, the ecological severity of the end Ordovician event was considered even less significant than that of the Serpukhovian, and is ranked only sixth within the eleven largest Phanerozoic crises since the beginning of the Ordovician Period. South China offers a key opportunity to examine the ecological changes through the end Ordovician event in detail. Recently, to test the ecological change through the end Ordovician mass extinction, a study carried on by Prof. HUANG Bing, CAS Academician RONG Jiayu and Prof. ZHAN Renbin from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences together with David A.T. Harper from Department of Earth Sciences, Durham University, UK. The study based on the data from the Cathaysiorthis fauna which dominated by brachiopods from the uppermost Ordovician to lowermost Silurian of SE China, succeeding the cool-water Hirnantia Fauna. The fauna is abundant and has a relatively high diversity; these data were reported with the detailed systematic descriptions of the fauna. The spatial and temporal ranges of more than 6,500 identified specimens, from 10 collections derived from 6 localities were investigated by network and cluster analyses, nonmetric multidimensional scaling and a species abundance model. The ecological circumstances of the survival brachiopod fauna after the end Ordovician mass extinction were evaluated. Other, older brachiopod faunas, Altaethyrella fauna and Foliomena fauna, characterizing the late Katian within the same area are compared in terms of diversity, population structure, benthic assemblage zones and relative abundance together with their major components to help further elucidate the ecological ‘turnover’ through the end Ordovician extinction event in South China. Depth zonations and structure of brachiopod assemblages along an onshore-offshore gradient in the late Katian were similar to those in the latest Ordovician–earliest Silurian (post–extinction fauna). The widths of ecological range are similar between before and immediately after the crisis that may suggest the limited ecological effect of the event. Within this ecological framework, deeper-water faunas are partly replaced by new taxa; siliciclastic substrates continued to be dominated by the more ‘Ordovician’ orthides and strophomenides, shallow-water carbonate environments hosted atrypides, athyridides and pentamerides, with the more typical Ordovician brachiopod fauna continuing to dominate until the late Rhuddanian. The end Ordovician extinctions tested the resilience of the brachiopod fauna without damage to its overall ecological structure; that commenced later at the end of the Rhuddanian. Reference: Huang Bing, Harper D A T, Rong Jiayu, Zhan Renbin. 2017. Brachiopod faunas after the end Ordovician mass extinction from South China: Testing ecological change through a major taxonomic crisis. Journal of Asian Earth Sciences, 138: 502–514.
SEM images of Diestheria longinqua Chen, in Zhang et al., 1976, emend.（Fig. 1 a light microscopy image) Clam shrimps (conchostracans) are large freshwater branchiopod crustaceans with a chitinous carapace (a few millimeter to two centimeters in size) that have a long geological history extending back to the Devonian. Extant clam shrimps normally inhabit quiet, alkaline freshwater pools, and often occur in temporary water bodies like rice field and even rain pools. They are useful for biostratigraphic subdivision and correlation of non-marine successions. The fossil spinicaudatan genus Diestheria Chen is an important component of the diverse Eosestheria fauna of the Early Cretaceous Jehol Biota in northern China. The studied type specimens of Diestheria longinqua Chen, in Zhang et al., 1976 were originally collected from the Lower Cretaceous Yixian Formation at Dakangpu of Yixian County, western Liaoning Province, northeastern China. They are deposited in the collection of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPCAS). The holotype (NIGPCAS 15462) is an external mould of a left valve and the paratype (NIGPCAS 15463) is a right valve. Most of the previous studies on the palaeontology of fossil clam shrimps have used a light microscope. This means that some morphological characters of potential taxonomic value were difficult to see clearly. Recently, M.S. LI Yuling, M.S. TENG Xiao, Prof. LI Gang from NIGPCAS and Prof. MATSUOKA Atsushi from Niigata Univ. re-examined the paratype specimen (NIGPCAS 15463) of Diestheria longinqua using a LEO 1530 VP scanning electron microscope (SEM). And the morphological re-examination under an SEM revealed morphological features on the carapace that have not been recognized previously: 1) growth lines with fine ridges; 2) radial lirae intercalated with small irregular reticulation on the growth bands in the postero-middle part of the carapace. The here discovered delicate reticulation between radial lirae is different from the evenly distributed puncta found in Neodiestheria. This study indicates that it is necessary to carry out a further morphological study on other species of Diestheria in the future. The research was recently published in the journal Sci. Rep. Niigata Univ. (Geology).This research was funded by the National Natural Science Foundation of China. Related information of this paper: Yuling LI, Xiao TENG, Atsushi MATSUOKA, Gang LI, 2017. SEM morphological study of clam shrimp Diestheria (spinicaudatan) of the Jehol Biota of China. Sci. Rep.Niigata Univ. (Geology) , No. 31, 69？74.
Clam shrimp Ordosestheria multicostata Clam shrimps (conchostracans) are freshwater branchiopod crustaceans with a hinged chitinous or complex chitin-mineral carapace. They are known in the fossil record from the Devonian to recent. Since the Pennsylvanian, clam shrimps have been an important and widespread component in non-marine, aquatic biotopes. They are useful for biostratigraphic subdivision and correlation of non-marine successions. The Yanjiestheria fauna occurs widely in the non-marine Lower Cretaceous rocks of East Asia and is principally composed of Neodiestheria, Orthestheria, Orthestheriopsis and Yanjiestheria. The nominated genus Yanjiestheria Chen in Zhang et al., 1976 was erected basing on specimens collected from the upper Albian Dalazi Formation in the Yanji Basin, Jilin Province, north-eastern China, and has been reported subsequently from the Lower Cretaceous in the south-eastern China, north-western China, Korea and south-western Japan. Recently, M.Sc. TENG Xiao and Prof. LI Gang from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences recovered species of Ordosestheria from the upper Albian Dalazi Formation in north-eastern China, which were previously identified as orthestheriids. This means that the distribution of ordosestheriids is wider than we thought before, and this genus can be an index genus for the subdivision of the non-marine sequences in China. According to previous studies the authors of the present research tentatively propose that ordosestheriids first originated from northern Africa in the early Barremian, during the early Aptian transgression they escaped from northern Africa and dispersed to the Ordos Basin of eastern Asia, then they further dispersed eastward to the western palaeo-Pacific coastal area and colonized in the Yanji Basin in late Albian. This research was funded by the National Natural Science Foundation of China, and by Chinese Academy of Sciences (XDPB05). Related information of this paper: Xiao Teng, Gang Li. 2017. Clam shrimp genus Ordosestheria from the Lower Cretaceous Dalazi Formation in Jilin Province, north-eastern China. Cretaceous Research, doi: 10.1016/j.cretres.2017.06.011.
Transverse section of fern-like plant Shougangia stem from the Upper Devonian of China A further study on the anatomy of Shougangia bella from the Late Devonian (Famennian) of South China is carried on the workgroup of Prof. XU Honghe from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Prof. Wang Deming from Peking University. The study release the anatomy feature of Shougangia and provide a reconstruction based on its known morphology, which was studied by them previously. Shougangia stems contain a dissected stele with a four-ribbed and an elongatecurved primary xylem segments changing to three elongate and slightly curved segments. Primary branches have a dissected stele with three similar primary xylem segments as in stems. The primary xylem of the stems and primary branches is mesarch, and individual primary xylem segments bear peripheral protoxylem strands and are surrounded by secondary xylem. Shougangia is anatomically compared with fern-like plants, zygopterid ferns and early seed plants, verifying its uncertain affinity at class and order levels as suggested by morphology, or representing a new order within the Cladoxylopsida. By the Late Devonian, besides the abrupt drop of atmospheric CO2 levels, the presence of secondary xylem may correlate well with the primary radiation of leaves (megaphylls) of euphyllophytes (e.g. fern-like plants, sphenopsids, progymnosperms and seed plants). Reconstruction of morphology (A) and anatomy (B–D) of the Late Devonian fern-like plant Shougangia from China Reference: Wang D-M*, Zhang Y-Y, Liu L, Xu H-H*, Qin M, Liu L. 2017. Reinvestigation of the Late Devonian Shougangia bella and new insights into the evolution of fern-like plants, Journal of Systematic Palaeontology. Doi: 10.1080/14772019.2017.1289269
A diminutive euphyllophyte, Douaphyton levigata, from the Middle Devonian of Xinjiang, the vegetitave and fertile speicmens. The grid in the upper right corner of the left fig is 1 mm wide. Devonian (420-360 Ma) witnessed a serial of dramatic landscape changes. A variety of land plants, including early ferns, lycopsids and zosterophylls, appeared in the lands of Devonian world. The first forest also occurred in the Devonian. The West Junggar, Xinjiang, China, with well-developed Devonian sequences and abundant plant fossils, has become a representative and significant area working on Middle Devonian flora. Diminutive Devonian plants (axis width less than 2 mm), for a long time were neglected for the reason of small size and that it is hard to fine organic connected specimens of vegetative and fertile organ. As a result, few study was carried on diminutive Devonian plants, which, however, act as a significant group to study plant and flora evolution, diversity and palaeophytogergraphy. Recently, a diminutive euphyllophyte, Douaphyton levigata gen. et sp. nov., is described from the upper Middle Devonian (Givetian) Hujiersite Formation of West Junggar, Xinjiang, China, by Prof. XU Honghe from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his collegues. The plant consists of more than three orders of axis branching, each axis being less than 2 mm wide. The second-order axes are short, laterally and alternately attached to the main axis. The third-order axes are paired and anisotomously divided, bearing the vegetative appendages or the fertile units. The fertile unit consists of a short recurved axis giving off up to four short pedicels along one side, each of which bears one to four pairs of terminal sporangia. The plant was named after the geologist Mr. DOU Yawei, who worked on geologic survey to Xinjiang in 1970-1980s. Douaphyton has a three-dimensional branching system that has an intermediate form in the evolutionary context of euphyllophytes and lignophytes. It is also proposed that complex branching developed in multiple groups in the Middle Devonian. Reference: Xu, H.-H., Wang, Y., Tang, P., Wang, Y., 2017. A new diminutive euphyllophyte from the Middle Devonian of West Junggar, Xinjiang, China and its evolutionary implications. Alcheringa.
Ankitokazocaris chaohuensis. scale bars equal 5 mm Thylacocephala, though only been recognized for 25 years, has been considered a peculiar group worthy of detailed anatomical and phylogenetic studies. They are benthic arthropods showing large, laterally flattened ovoid/sub-trapezoidal bivalved carapace that encompasses the entire body and have a typical anterior rostrum-optic notch complex. Generally they have large compound eyes, three large raptorial appendages, 8 gills and numerous posterior appendages. Their long temporal distribution, from the early Palaeozoic to the Late Cretaceous, is furnished by patchy records that clearly reflect the availability of Fossil-Lagerst？tten. The taxonomy and ecology of this group has been controversial due to the low diversity and lack of complete specimens. In the Chaohu Area of Anhui Province, a complete strata of the Early Triassic can be observed. The Chaohu Fauna, represented by the diversified marine reptiles and fishes from the upper part of Nanlinghu Formation (Spathian, Olenekian), has been regarded as a marker of the full recovery of marine ecosystem after PTME. Recently, Dr. JI Cheng from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and her collegues discovered new material of thylacocephalan from the Chaohu Fauna and it is also the first report of this group in the Triassic of South China. More than one species can be recognized but majority belongs to a new species, Ankitokazocaris chaohuensis, suggesting a close geographic correlation with Madagascar and Japan during the Spathian of Early Triassic. From the bed yielding A. chaohuensis, we also found some coprolite fossils, some of which contain conodonts inside. The size and structure of these coprolites can rule out the marine reptiles and fish from the same fauna as producers. Dr. JI compared the relative size of gut and carapace of Silurian thylacocephalan Thylacares brandonensis and their coprolites and found that these thylacocephalans from the same bed could possibly have produced the coprolites after eating conodont animal. This is the first report of the predation between thylacocephalan and conodont animal. On the other hand, thylacocephalans have large compound eyes and large raptorial appendages, suggesting they are capable of detecting and grasping small prey like shrimp or maybe even conodont animal of similar size. Dr. JI also have a few specimens that preserve conodonts inside the partial carapace where the latter was broken. They might be related with gut remains but still need further evidence. reconstruction of Ankitokazocaris chaohuensis (By YANG Dinghua from NIGPAS) This research has been recently published on-line in Pal？ontologische Zeitschrift, founded by National Science Foundation of China, CAS Key Laboratory of Economic Stratigraphy and Palaeogeography and State Key Laboratory of Palaeobiology and Stratigraphy (NIGPAS). Reference: Cheng Ji, Andrea Tintori, Dayong Jiang and Ryosuke Motani, 2017. New species of Thylacocephala (Arthropoda) from the Spathian (Lower Triassic) of Chaohu, Anhui Province of China. Pal？ontologische Zeitschrift, DOI: 10.1007/s12542-017-0347-7.
Fig. 1 Some charophytes from the Pingyi Basin. A-C. Feistiella anluensis; D-I. Peckichara varians. var ss="图1. 山东平邑盆地部分轮藻化石属种"; if(ss=="") document.getElementById("d0").style.display="none";
The Cretaceous-Paleogene boundary (K/Pg boundary) marks the beginning of the Cenozoic, and is one of the most important geological boundaries. The end-Cretaceous extinction is one of five mass extinction events, leading to the extinction of ammonites and belemnites in the sea. Also it is the end of dinosaur’s age. The K/Pg boundary is recognized as the boundary clay and the GSSP for the base of Danian stage is at the base of the clay. However, it is difficult to find the boundary clay in non-marine strata. Charophytes are usually very abundant in the non-marine strata near the K/Pg boundary, and the significant changes of charophyte flora can help to recognize the K/Pg boundary. Recent investigation conducted by the Dr. LI Sha from “Modern terrestrial ecosystems origin and early evolution research team” at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, cooperated with Carles Martín-Closas from the University of Barcelona, studied the change of charophyte floras from the Cretaceous–Paleogene transition in the Pingyi Basin, China and correlated it with European charophyte floras under the same age. The Cretaceous–Paleogene boundary was raised in the Pingyi Basin and the results were published on the Journal of Cretaceous Research. Traditionally, the identification of charophytes in China is usually based on individual or a few gyrogonites but not the whole population. Such studies lack statistical measurements of the population and a uniform taxonomic standard, and do not consider the population characteristics and intraspecific variation. So it is difficult to make an intercontinental charopyhte biostratigraphic correlation and calibrate the K/Pg boundary in China. In study of the Pingyi Basin, Shandong Province, both traditions of identification from China and Europe were combined. For example, Porochara anluensis used in China was in fact belonged to the genus Feistiella according to observing the sections of basal plates. The intraspecific variations Peckichara varians was recognized based on population measurement and analysis. The abundant species Gobichara deserta around the Cretaceous–Paleogene boundary is in fact a younger synonym of Microchara cristata. (Fig. 1). Fig. 2 Paleobiogeography of Microchara cristata in the Maastrichtian and early Paleocene, showing its Eurasian distribution. Paleogeography modified from Blakey (2006) with data plotted on a map at 65 Ma. var ss="图2. 山东平邑盆地马斯特里赫特期至古新世早期Microchara cristata的地理分布，显示其欧亚分布。古地理图改自Blakey（2006），65Ma"; if(ss=="") document.getElementById("d1").style.display="none";
Based on a concensus of identification standard, a new biozonation is proposed which encompasses two biozones based on species with broad paleoecological requirements and a Eurasiatic distribution (Fig. 2, 3). European terrestrial Cretaceous–Paleogene boundary is mainly studied based on charophyte biozonations, the results can also be used in the research of Chinese terrestrial Cretaceous–Paleogene boundary. These are the Microchara cristata biozone starting in the latest Campanian and lasting at least until the earliest Danian and the Peckichara varians biozone encompassing the late Danian–earliest Eocene. The former can be correlated with biozones established by Galbrun et al. (1993) and Vicente et al. (2015) and calibrated to the GPTS, and the latter was correlated with Paleocene larger foraminifera in the Northern Pyrenees (Massieux et al., 1981). Therefore, the Cretaceous–Paleogene boundary from the Pingyi Basin was proposed to be in the first member (upper sub-member) of the Bianqiao Formation. Reference: Li, Sha, Wang, Qifei, Zhang, Haichun, Lu, Huinan, Martín-Closas, Carles* (2016) Charophytes from the Cretaceous–Paleogene transition in the Pingyi Basin (Eastern China) and their Eurasian correlation. Cretaceous Research, 59: 179-200
Fig. 3 Paleoenvironmental models summarizing the paleoecological distribution of charophyte floras in the Pingyi Basin (Gucheng and Bianqiao Formations) during the Maastrichtian and Paleocene.
Recently, ZENG Han (PhD student) and his colleagues from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences described in detail the appendages of an early Cambrian trilobite Hongshiyanaspis yiliangensis Zhang & Lin in Zhang et al., 1980 (Redlichiida, Metadoxididae) from the Cambrian Xiazhuang fossil assemblage at the suburban of Kunming, Yunnan. This is the seventh trilobite species with complete appendages described and reconstructed in the world, and the second one in China after Eoredlichia intermedia from the Chengjiang Lagerst？tte. The new data supports the mandibulate affinities of trilobites. Trilobites are one of the most diverse extinct groups of arthropods that inhabited Paleozoic seas from the Cambrian explosion to the end-Permian mass extinction (~ 520–250 Ma). So far, more than 20,000 trilobite species have been discovered. However, nearly 99% trilobite species are named based on morphology of exoskeletons, the soft bodies of trilobites are poorly known. In particular, complete walking limbs of trilobites have only been reconstructed in six species from exceptionally preserved fossil deposits. This limited knowledge of the trilobite soft anatomy, especially appendages, has long constrained our understanding on the evolutionary position of trilobites on the arthropod tree of life. Owing to increasing numbers of exceptionally well-preserved arthropods from the Cambrian Chengjiang (Yunnan, China) and the Burgess Shale (British Columbia, Canada) during the last two decades, the artiopods (meaning bearing a complete set of similar appendages), a miscellaneous group of Cambrian arthropods possessing similar body plans and appendage structures with trilobites, are widely accepted as the closest relatives of trilobites. However, no consensus has been reached on the closest extant arthropod group of trilobites and artiopods, as either Chelicerata or Mandibulata. The appendages of H. yiliangensis exhibit the common architecture revealed by other trilobites and artiopods by consisting of a pair of uniramous antennae followed by a series of paired homonomous biramous limbs. The antennae in holaspid individuals comprise up to 27 spinous podomeres and their ontogeny occurs by lengthening of the podomeres. The post-antennal biramous limbs are similar to those in other trilobites and artiopods by having a single-segmented protopodite and an endopodite comprising seven segments, but possess a unique wide tripartite exopodite with long setae. Appendages of trilobites, artiopods and other upper stem-group euarthropods are compared and summarized. The H. yiliangensis appendages highlight the high morphological disparity of exopodites and the conservativeness of endopodites in trilobites and artiopods. This morphological pattern, together with similar body patterning seen in crustaceans but not in chelicerates, supports the mandibulate affinities of trilobites and at least some artiopods. This research was funded by the National Natural Science Foundation of China, the Ministry of Science and Technology of China, and the Chinese Academy of Sciences. Article information: Han Zeng, Fangchen Zhao*, Zongjun Yin, Maoyan Zhu. 2017. Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods. Geological Magazine: 1–23. doi: 10.1017/S0016756817000279. (*corresponding author)
Early Cambrian trilobite Hongshiyanaspis yiliangensis preserved with complete appendages (Image by Zeng et al.) Reconstruction of limbs of early Cambrian trilobite Hongshiyanaspis yiliangensis (Image by Zeng et al.)
