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    2022,61(1):1-19, DOI: DOI:10.19800/j.cnki.aps.2020020
    Abstract:
    This study of proasaphiscid trilobites is based on some type specimens and new materials (topotypes) collected from the type sections at Longwangmiao, Qujing in eastern Yunnan as well as at Sanwan, Nangao, Danzhai, Kaili and Meitan in Guizhou. The diagnoses and occurrences of Kuetsingocephalus and Danzhaiaspis have been revised, and the ratio of preglabellar field to glabellar length is here considered as the main crucial distinction between the two genera. In Kuetsingocephalus the ratio of preglabellar field to glabellar length is less than 24%, but in Dan-zhaiaspis it is more than 30%. In Danzhaiaspis all pleural ribs are visible, while in Kuetsingocephalus only the first pair of pleural ribs is visible. One new genus and three new species have been established herein: Qizuoshania tang-shanensis gen. et sp. nov., Danzhaiaspis intermedius sp. nov., and Kuetsingocephalus fengrunensis sp. nov. With exception of oryctocephalids, the proasaphiscid trilobites are of very important significance for defining the boundary of Cambrian Series 2 and Miaolingian Series in North China Platform and the Yangtze Platform owing to its wide distribution and rapid evolution in China.
    2022,61(1):20-35, DOI: 10.19800/j.cnki.aps.2020008
    Abstract:
    Microbially induced sedimentary structures (MISS) and metazoan bioturbation structures (trace fossils) are abundant in Upper Permian–Lower Triassic Sunjiagou, Liujiagou and Heshanggou formations in Xingyang, Jiyuan, Dengfeng, Yiyang and Gongyi areas, western Henan, North China. The MISS can be divided into 25 subtypes belonging to three major groups, i.e., mat growth, mat destruction and mat decay structures. Thirteen ichnospecies of 6 ichnogenera are recognized from the Liujiagou and Heshanggou formations. The MISS and metazoan bioturbation structures (trace fossils) vary from the bottom to the top of the strata with some patterns. The MISS first appeared in the Sunjiagou Formation, became abundant in the Liujiagou Formation and disappeared completely in the Heshanggou Formation. The metazoan bioturbation structures first appeared in the middle and upper parts of the Liujiagou Formation, gradually increased in the upper part of the Heshanggou Formation, and basically recovered to the diversity level of the pre-Permian–Triassic catastrophe in the Middle Triassic Youfangzhuang Formation. The MISS and the metazoan bioturbation structures cooccur only in the Liujiagou Formation. The results show that, in general, there is a negative correlation between the development of the MISS and the metazoan bioturbation structures in the study area, and there is a coupling variation of the two types of structures.
    2022,61(1):36-50, DOI: 10.19800/j.cnki.aps.2021011
    Abstract:
    Coprolites (fossilized faeces) are important paleobiological sources for inferring diet, behavior and physi-ology of animals that produced them and predator-prey interactions among animals. Therefore, coprolites are pivotal in reconstructing the trophic structure of a paleoecosystem. Abundantly and exceptionally preserved coprolites are documented from the 35th layer of the Ladinian (Middle Triassic) Xingyi Fauna in the Nimaigu section, Xingyi, Guizhou Province and are categorized into seven morphotypes for the first time. Information about the inclusions was obtained by an optical microscope and a scanning electron microscope. The inclusions mainly consist of bone fragments of Keichousaurus hui and fish scales. Fragments of invertebrates are rare. The size of the coprolites and the absence of spiral-shaped structure, together with relatively small fragments of the inclusions in the coprolites, suggest that the producers are carnivorous marine reptiles. Taking the information of the lower marine reptile assemblage of Xingyi Fauna into account, the producers might include Nothosaurus, Lariosaurus or Thalattosauria. The seven morphotypes of coprolites indicate the existence of at least one trophic level discrepancy among marine reptiles. This result provides important information for the reconstruction of the marine ecosystem in the Ladinian. In addition, the presence of bacteria and the anaerobic environment with high content of mud may have enhanced the preservation of coprolites.
    2022,61(1):51-64, DOI: 10.19800/j.cnki.aps.2021006
    Abstract:
    The Norian (Upper Triassic) marine carbonate successions of the Sanhedong Formation were formed in the Lanping-Simao Block, western Yunnan Province. In this study, conodont fossils from the Sanhedong Formation were collected and identified. The conodont assemblage, dated as early Norian (Lacian), consists of Epigondolella vialovi,Epigondolella uniformis and Epigondolella aff. Triangularis. Facies and microfacies analyses of the Sanhedong Formation, in combination with field observation at the Sanhedong section, reveal three main facies, i.e., restricted-marine platform, open-marine platform and platform-margin reefs. They are further subdivided into nine microfacies. The presence of hydrothermal minerals, such as garnets, and the high conodont alteration index (CAI = 5) throughout the Sanhedong Formation indicate that hydrothermal actions may have affected the diagenetic process. The hydrothermal activities may be related to the upwelling of geothermal brine resulted from the subsidence of the continental rift margin and tectonic plate collision during the post-diagenetic process.
    2022,61(1):65-87, DOI: 10.19800/j.cnki.aps.2020046
    Abstract:
    Based on studies of the six sections of the Jurassic Buqu Formation in Shenglihe, Donghu and Maomaoshan areas in the south central parts of the North Depression of the Northern Qiangtang Basin, their lithological characters, and their rich paleontological data (including abundant brachiopods and bivalves), we propose that the age of the Buqu Formation is constrained to the Middle Jurassic Bathonian to early Callovian (probably extending to early Bajocian). Results from our observations and regional correlations indicate that the Buqu Formation in the Northern Qiangtang Basin is diachronic. Characteristics of rock assemblages of the Buqu Formation indicates that the sediments can obviously divided into three parts. Both the lower and upper parts consist of a series of low-energy carbonate rocks dominated by microcrystalline and grain-muddy structures, and the middle part consists of a series of high-energy carbonate rocks dominated by pelsparite. Combined with the palaeoecological habits of the paleontological, the overall depositional environments of the Buqu Formation are considered as a near-shore shallow water open platform and a platform margin carbonate sedimentary system, which constitute multiple depositional cycles. This basic data provides a foundation for further analysis of the lithofacies paleogeography of the Buqu Formation in the south central parts of the Northern Qiangtang Depression.
    2022,61(1):88-106, DOI: 10.19800/j.cnki.aps.2020027
    Abstract:
    A total of 54 genera and 58 species of vertebrates, including fishes, amphibians, reptiles and mammals, have been reported from the Yanliao Biota, but the diversity and formation mechanism of vertebrates have not been well-studied in detail based on biological analysis. Here, a statistical analysis of the vertebrates in the Yanliao Biota and a detailed comparison with other biotas of similar age are present, which provides significant evidence for the diversity of vertebrates and the formation of the Yanliao Biota. Although the early Daohugou Biota and the late Linglongta Biota are continuous in time, they show different characteristics of biological combination of vertebrates, respectively. Yanliao Biota including a large number of invertebrates and vertebrates and plant fossils is significantly different from other biotas of similar age, such as the Wucaiwan Fauna from Xinjiang and Dashanpu Dinosaur Fauna from Sichuan Basin. Dinosaurs from the Yanliao Biota only contain small theropods and some early ornithischians. But Yanliao Biota is very rich in pterosaurs and mammals. Vertebrates from the Yanliao Biota have high ecological diversity and a unique combination of taxa groups. Some evidence indicates that there may exist geographic isolation between East Asia and other regions during this period. Combined with the characteristics of terrestrial vertebrate assemblage, it can be inferred that there may have been some obstacles in the communication between vertebrates of the Yanliao Biota and the outside world.
    2022,61(1):107-122, DOI: 10.19800/j.cnki.aps.2021031
    Abstract:
    Coprolites are the fossilized animal faeces while bromalites are the fossilized food remains ingested by ancient animals. As an important type of trace fossils, bromalites carry copious palaeoecological information that is not available through the study of body fossils. Therefore, studying these fossils opens a window for understanding the behavioral ecology and predator-prey relationship of ancient animals and food chain/web structures of ancient ecosystems. Further, fossilized parasites within coprolites provide direct evidence on the origin and evolution of intestinal parasites. Besides, coprolites produced by potential hominins in Cenozoic caves provides pivotal clues in elucidating the recipes and health conditions of ancient humans. In addition, plant remains (pollen and phytoliths) within Mesozoic and Cenozoic coprolites supply crucial evidence from which palaeo-vegetation, climate and animal-plant relationships can be well reconstructed. This paper reviews the history of bromalite studies and sums up the recent advances of applying bromalite to various aspects of palaeoecologic interpretations mentioned above. It is concluded that bromalites serve as significant proxies in palaeoecological interpretations. Finally, we sum up new techniques (such as CT scan technology) used in bromalite studies and propose possible future development directions, which we hope may boost the bromalite studies in China.
    2022,61(1):123-135, DOI: 10.19800/j.cnki.aps.2021056
    Abstract:
    Using plants as a proxy to estimate climate is one of the main approaches to quantitatively reconstructing past climate parameters. The parametric function of Climate Reconstruction Analysis using Coexistence Likelihood Estimation (P-CRACLE) is a quantitative climate reconstruction method based on biological taxonomy. P-CRACLE uses worldwide plant distribution data to obtain corresponding climate parameters. This method assumes that the occurrence of a species is normally distributed along the variables of the climate to calculate the climate intervals where plants coexist. Based on 165 modern floras of the world, the reliability of this method is well verified, but there are still controversies over the acquisition and processing of plant distribution and climate data. To further verify the reliability of this method, we selected 26 research sites of modern floras, obtained plant distribution data from the Global Biodiversity Information Facility (GBIF) database and the climate parameters by using the meteorological grid data (WorldClim 2.1) with two different resolutions (0.5 arcminute and 2.5 arcminute). We apply the traditional mutual climate range (MCR) and P-CRACLE to jointly calculate the climate parameters for all research sites. The results show no apparent difference when using different resolutions of climate grid data. Annual average temperatures obtained using MCR and P-CRACLE are 8.3 ℃ and 1.7 ℃, respectively, and the average resolutions of annual average precipitation are 1120 mm and 280 mm, respectively. Therefore, the resolution of climate intervals obtained by P-CRACLE is far more accurate than that by MCR. Then, based on the percentile of each plant taxon’s given climate parameter to the observed value of the research site, the plant taxon with a percentile higher than 10% and lower than 90% was selected to re-analyze the coexistence of P-CRACLE. Comparison with the coexistence results of previous studies shows that the accuracy of the reconstruction is significantly improved, providing a direction for increased accuracy of quantitative paleoclimate reconstruction in the future. This study suggests that P-CRACLE can be applied to the quantitative reconstruction of paleoclimate since the Cenozoic with very high resolution and reliability.
    2022,61(1):136-150, DOI: 10.19800/j.cnki.aps.2021037
    Abstract:

    The delicate internal organs of the Cambrian arthropods, such as the digestive and nervous systems, provide significant insights into the evolution of early life and the Cambrian ecosystems. As such, their original morphology and preservation mechanisms have been the focus of research in recent years, indicating that the exploration on the preservation mechanisms of soft tissues requires a variety of textural experiments and theories. As a branch of taphonomy, the experimental taphonomy provides important theoretical supports and empirical means for interpreting anatomical structures during fossilization of dead bodies and the formation of a Lagerst?tte. We present this experimental means on the guts and ventral nerve cords of the arthropod Penaeus vannamei under different temperatures and combined conditions in order to observe the degradation process of these soft tissues. The result shows that the degradation trends of guts and ventral nerve cords are similar at different temperatures, but at different rates. The rate and degree of degradations of gut and ventral nerve cord materials at 25 ℃ are significantly higher than those at 10 ℃. At the same temperature, the degradations of guts and ventral nerve cords are different in the early stage. The morphology and the amount of biofilms produced by the degradation at 10 ℃ are totally different. The amount of biofilms produced by the combination of guts and ventral nerve cords is much higher than those produced separately by guts and ventral nerve cords. It is also difficult to distinguish the biofilms produced by the guts and ventral nerve cords. Therefore, temperature is an important factor affecting the speed and degree of gut and ventral nerve cord degradation. In addition, microorganisms play an important biochemical role during the degradation process of biological organs and tissues. The degradation process of biological organs and tissues, associated with the formation of biofilm, has a great influence on the morphological characteristics of fossils, especially the preservation and interpretation of delicate internal structures

    2022,61(1):151-164, DOI: 10.19800/j.cnki.aps.2021044
    Abstract:
    Chabu area in Otog Qi, Inner Mongolia, is a rare fossil producing area of dinosaur footprints in the world, which is rich of dinosaur tracks from Early Cretaceous. However, these footprint fossils are experiencing different degrees of weathering in the field. In order to protect these fossils in-situ , the Otog Field Museum of Geological Vestige was built on the Tracksite No. 8. Whereas, it was found that the weathering degree of indoor footprints was more serious than that in the field, especially the area within the museum near the surrounding walls, and the surface of the footprints gradually became efflorescence and broken, and some even completely disappeared. In order to understand this weathering phenomenon, fossil rocks of the same stratum inside and outside the museum were tested by means of polarized light microscope (PM) observation, X-ray diffraction (XRD) analysis, mercury intrusion test (MIP), ion chromatography (IC) analysis, Raman spectroscopy (Raman) analysis, Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscopy (SEM-EDS) analysis in this article. It is found that the indoor rock has a higher porosity and larger pore size, and soluble salts content is 2 times that of the surface rock as well as 11 times of subsurface rock. The soluble salts are mainly NaCl and Na2SO4. Though simulated aging tests, it is found that the damage of soluble salt is greater than freeze-thaw, and Na2SO4 is the most damage salt. Therefore, it is indicated that the weathering mechanism of dinosaur tracks in the museum is the combined action of groundwater and surface water formed by rainfall, which leads to strong water-salt activity of Na2SO4. It is found that the nitrocellulose varnish, which was used as consolidant and sealing material, did not have a good protective effect. Some suggestions are put forward to deal with this problem.
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    Abstract:
    The Ordovician in Yunkai area of western Guangdong Province mainly consists of sandstone, pelitic siltstone, silty mudstone and pebbly sandstone, and mudstone with intercalated carbonate rock lenses and conglomerates. The Ordovician includes the Lower Ordovician Luohong Formation and Luodong Formation, Middle Ordovician Dongchong Formation, and Upper Ordovician Lanweng Formation. Fossil bivalves, including the new taxa described in this paper, were collected from an about 2-meter-thick bed of gray to grayish yellow silty mudstone and pelitic siltstone of the upper part of the Dongchong Formation. The collection includes about one thousand bivalve specimens, which represent more than 22 species of 16 and several unnamed genera and may a possible new taxon. We report a group of unique bivalves including two new species of Yunannia gen. nov. of a new family Yunanniidae Zhang et Niu and a new superfamily Yunannioidea Zhang et Niu. This group demonstrate combined features normally attributed to different bivalve taxa. A small number of trilobites, including Nileus sp., Lonchobasilicus sp., Calymenesun tingi Sun, Calymenesun sp., Asaphopsis? sp., and brachiopods, including Paralenorthis sp., Aegira sp., Leptellina sp., Obolus? sp., Strophomena sp. and Nicolella sp., cooccur with the bivalves and indicate the Middle Ordovician age. SYSTEMATIC PALEONTOLOGYClass Bivalvia Linnaeus, 1758 in 1758–1759 Subclass Autobranchia Grobben, 1849 Infraclass Pteriomorphia Beurlen, 1944 Cohort Uncertain Superfamily Yunannioidea Zhang et Niu superfam. nov. Description Shell small, mytiliform, umbos anterior to terminal; strong inequilateral; buyssal sinus faint; the area beneath and anterior umbo edentulous; posterior to umbo a row of discrete chevron taxodont teeth; large anterior adductor muscle scar located in the umbonal angle and occupies the large and wide umbonal septum together with the anterior pedo-byssal retractors; posterior muscle scar unknown; external ligament, opisthodetic, submarginal; ligamental area narrow with 2-ranks of ligamental grooves and ridges, which are gently arched and extended continuously away from the dorsal margin; shell surface with faint comarginal growth lines. Remarks The Yunannioidea, a new superfamily of pteriomorphians is established based on the genus Yunannia proposed in the present paper. The Yunannia, the sole genus of the new superfamily Yunannioidea, is characterized by mytiliform outline, one posterior row of chevroned teeth, the large anterior adductor muscle scar located in the umbonal angle and inserted on the umbonal septum together with the anterior pedo-byssal retractor, and the arched two ranks of ligamental grooves and ridges which extend continuously away from dorsal margin. On the basis of features such as mytiliform, the musculature, and ligament, the Yunannioidea may be placed into the Cohort Mytilomorphi!. However, the genus Yunannia has only one row of posterior chevroned teeth. Together with its unusual hinge dentition, the new superfamily can be distinctly distinguished from other members of the same cohort. Meanwhile, features including the taxodont dentiotion and the two ranks of ligament indicate that Yunannia is likely in connection with Subcohort Ostreioni. Hence, the position of Yunannia at cohort level is undetermined. The genus Yunnania most possibly represents a new order of the infraclass Pteriomorphia. Family Yunannidae Zhang et Niu fam. nov. urn:lsid:zoobank.org:act:8A609836-4A82-4C6A-97B1-18168E761 891 Type genus Yunannia Zhang et Niu Yunannidae is the sole family of the new superfamily Yunannioidea. Distribution Middle Ordovician, Guangdong, China. Genus Yunannia Zhang et Niu gen. nov. urn:lsid:zoobank.org:act:B09DAFBA-A54D-4621-8FCD-07D8882 A6584 Type species Yunannia gankengensis Zhang et Niu gen. et sp. nov. Diagnosis Shell mytiliform, umbos anterior to terminal, with a row of posterior, discrete chevron taxodont teeth; anterior adductor muscle scar large and pedo-byssal retractor inserted on umbonal septum; ligament external and opisthodetic, extending continuously away from dorsal margin. Description The shell is small with height less than 21 mm. The shell shape is strongly inequilateral, mytiliform or narrow ovate with height longer than length. The umbos is anterior to terminal, projected and slightly incurved. Anterior lobe is absent. The dorsal-posterior margins are merged and widely arched. The anterior flange is thickened. The umbnal cavity is large and deep, separated by a lunate inner septum. The anterior adductor muscle scar is large and elliptical, located in the umbonalangle, and inserted on the umbanl septum together with the posteriorly extended pedo-byssal retractor. The growth line of anterior adductor muscle scar is present in one specimen. The anterior end of the anterior adductor scar is acuminate, likely marking the position of the pedal protractor but is obviously merged with the anterior adductor. The posterior adductor and posterior pedal retractor are unknown. The holotype, a left valve, bears about 20 teeth and sockets, while each half of a paratype bears about 8–15 teeth. The area anterior to and beneath umbo is edentulous. All teeth are discrete and chevroned with concavities towards distal end. The anterior two or three teeth are small and the rest become gradually larger posteriorly, achieving the maximum size about midway along the row of teeth. The teeth diminish gradually in size toward the posterior end of hinge plate. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamental area is narrow and extends posteriorly to about 3/4–4/5 height of shell, with one rather coarse ligamental ridge and two grooves above and below it (as the first-rank of ligament), while the weak and faint ligamental ridges and grooves (as the second-rank of ligament) within the first-rank ligamental grooves and ridge. Because of the number of first-rank ligamental groove-ridge couplets, it is likely the preduplivincular ligament. However, if the second-rank of ligament is also considered, the total number of ligamnental groove-rige couplets is more than two or three. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. In addition, the arched shape of ligamental area is similar to the simple arched ligament. The holotype specimen shows faint growth lines on the inner surface of shell wall. Etymology Yunan, a geographic name of a county in Guangdong Province. Remarks This genus is the sole representative of Yunannioidea superfam. nov. It is characterized by features such as the mytiliform shell having a posterior row of chevroned teeth, and the arched two ranks of ligamental groove-ridge couplets extending continuously away from the dorsal margin. The large anterior adductor located in the umbonal angle and inserted on the umbanl septum together with anterior pedo-byssal retractor. In addition, the large and wide umbonal septum is another distinguishing feature of Yunannia. The new genus combines some main features normally attributed to different bivalve taxa. Its dentition of taxodont teeth is similar to the Paleotaxodonta. The new genus and Ambonychioidea of Pteriomorphia share some features, including the mytiliform shape, terminal umbos and byssal sinus. Both the new genus Yunannia and cyrtodontoids have the same characteristic of sub-umbonaledentulous area. The present new genus and Dreissenoidea of Heteroconcha have common characters such as the anterior muscle scar inserted on umbonal septum, the submarginal, long, extended arched ligament. With the combination of features listed above, the new genus clearly distinguishes itself from all other genera in those taxa. Age and distribution Middle Ordovician; Guangdong, China. Yunannia gankengensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:67E7B718-0211-4EBB-ADA9-898045A3 8637 (Figs. 3–5) Materials 8 specimens of internal moulds including 5 left valves and 3 right valves. Holotype: No. Ng4032, Paratypes: Ng4033, Ng4030, Ng4031, Ng1041. Diagnosis Height/length(width) ratio less than 1.5; ventral part of shell expanded and swollen. Description The shell is small, mytiliform, strongly inequilateral with height less than 20 mm. The height is longer than the length (width) with height/length(width) ratio less than 1.5. The umbos is terminal, projected and slightly incurved. The anterior lobe is absent. A faint byssal sinus is present at the upper part of anterior margin. The dorsal-posterior margins are merged and widely arched. A long and thickened anterior flange is present behind the anterior margin. A large umbnal cavity is separated by a lunate umbonal septum. The elliptical and large anterior adductor muscle scar is located in the umbonal angle, together with anterior pedo-byssal retractor, occupying the umbonal septum. The anterior adductor muscle scar being covered by growth line is showed in one paratype specimen (No. Ng1041). The anterior end of the anterior adductor scar is acuminate, which likely marks the position of the pedal protractor, but is obviously merged with the anterior adductor (as to otherwise indistinguishable). The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath the umbo is edentulous. Posterior to the umbo there is a row of teeth consisting of 13–20 discrete and chevroned teeth with concavities towards the distal end. The anterior and posterior two or three teeth are small with the maximum size at the midway along the tooth row. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamenal area is narrow, extending posteriorly away from dorsal margin to about 4/5 height of the shell with one rather coarse ligamental ridge and two grooves laid above and below it (as the first rank of ligament), which are subdivided by the weak and faint (as the second rank) ligamental ridges and grooves. Because of the number of the first rank ligamental groove and ridge couplets, it is likely the preduplivincular ligament. However, if the second-rankof ligament is also considered, the total number of ligamnental groove-rige couplets is more than 2–3. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. Faint growth lines are present on the shell surface. Measurement Holotype: No. Ng4032: height 17.5 mm, length 13, H/L = 1.35. Etymology Gankeng, a geographic name of Guangdong. Comparison The present new species evidently differs from Yunannia yunkaiensis gen. et sp. nov. in having mytiliform shape, shell becoming gradually wider towards ventral side, with the maximum width near the ventral part of the shell, and a height/length ration less than 1.5. The latter species has a narrow and narrow ovate shape and a height/length ration about 2. Occurrence Gankeng Village, Yunan County, Guangdong Province; Dongchong Formation, Middle Ordovician. Yunannia yunkaiensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:BE7BF3A3-3F07-4049-88F3-2EE989D4 E914 (Fig. 6) Materials 3 internal moulds of left valve. Holotype: No. Ng4035, Paratypes: Ng074, Ng4034. Diagnosis Shape narrow ovate and H/L ratio about 2.0. Description The shell is small, narrow ovate, strongly in-equilateral, 16.5–21 mm high. The height is much longer than the length with a H/L ratio of 2.0. The umbos is projected and slightly incurved. The anterior lobe is absent. The dorsal-posterior margins are merged and gently arched. The thickened anterior flange is relatively narrow. The umbonal cavity is separated by lunate, relatively narrow umbonal septum. The large and elliptical anterior adductor muscle scar is located in the umbonal angle, and together with the pedo-byssal retractor, inserted on umbanl septum. The anterior end of the anterior adductor scar is deeply inserted and becomes shallow poster-ventrally. The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath umbo is edentulous with a posterior row of hinge tooth consisting of more than 8 to 13 discrete and chevroned teeth with concavities towards the distal end. The ligament is external and epithetic, submarginal. The ligamental area is narrow, sub-parallel to the gently arched dorsal-posterior shell margin, extending posteriorly away from dorsal margin to about 3/4 height of shell, and with one rather coarse ligamental ridge and two grooves above and below it (as the first rank of ligament). The four weak and faint ligamental groove-ridge couplets (as the second rank of ligament) extend about 5 mm in length in the dorsal side of the groove of the first rank ligament. Surface ornaments of the shell are unknown. Measurement Holotype: No. Ng4035; height 21 mm, length 10 mm, ratio H/L = 2.0. Etymology Yunkai, a regional geographic name in Guangdong Province. Comparison The present new species is distinguished from the genotype, Yunannia gankenensis (gen. et sp. nov) by the narrow ovate shape with a H/L ratio of 2, and the slightly incurved umbo. In contrast to the latter species’ mytiliform shape and a H/L ratio less than 1.5. On the respect of shell shape, the present species is more or less similar to Mytilarca chenmungensis (Conrad) (Pojeta, 1966, pl. 37, figs. 8–18; pl. 38, figs. 1–5, 10), but it differs from the latter species by having a subumbonal edentulous area, a posterior row of taxodont teeth, a large anterior adductor muscle scar, and large anterior pedo-byssal retractors laid on unmbonal septum. Occurrence Gankeng Village, Yunan County, Guangdong Province, Dongchong Formation, Middle Ordovician.
    Abstract:
    Populus L. is an ecologically important tree genus in the Northern Hemisphere temperate forest. In this paper we summarize the Populus fossil records from the Paleogene and Neogene of the Tibetan Plateau with updated stratigraphic and chronological data. Fossil evidence shows that Populus first occurred in the plateau in the latest Eocene. The genus is well-documented in the southern and northern Tibetan Plateau in the Oligocene and Miocene, but lacking in the central plateau. Most of the fossil floras in the Tibetan Plateau containing Populus are temperate, deciduous and broadleaved, riparian vegetation, further confirming that the genus had favored a temperate and riparian environment in their early evolutionary history. Besides, the high diversity and prominent dominance of Populus in early Oligocene flora in the northern Tibetan Plateau suggests this region had played an important role in the early diversification stage of Populus.
    Abstract:
    The journey to understand the Cambrian explosion started with Creation, was subsequently succeeded by Darwinism, and became increasingly impacted by the theory of explosive evolution. The Cambrian explosion by nature is an explosion of animal body plans alongside episodic biomineralization, pulsed change of generic diversity, body size variation, and increase of ecosystem complexity. It is a polythetic event in natural history and manifested in many aspects. No simple, single cause can explain the entire phenomenon. Intrinsic and extrinsic causes were extensively discussed but they are merely prerequi-sites for the Cambrian explosion. Without the molecular evolution, there could be no Cambrian explosion. However, the de-velopmental system alone is insufficient to explain Cambrian explosion. Time-equivalent environmental changes were often considered as extrinsic causes, but the time coincidence is also insufficient to establish causality. Like any other evolutionary event, it is the ecology that makes the Cambrian explosion possible though ecological processes failed to cause a burst of new body plans in the subsequent evolutionary radiations. While the Cambrian explosion did take place under circumstances when the world oceans became habitable for various forms of animals, the developmental Gene Regulatory Networks (GRNs) were sufficiently complex for constructing complex forms, and resource supply was less restricted. It seems that opportunities were in every corner! Early metazoans shared seafloors with vendobionts for the last 20 million years of the Ediacaran, although their ecological relationships are less known. Metazoans followed the path of evolving organs and sys-tems, developing orderly repetition of body parts, and attempting possibilities, which enable the evolution of morphological, physiological, ecological variations and complexity. While vendobionts kept their less differentiated body designs, tis-sue-grade organization, and probably osmotic physiology. Consequently, Ediacarans died off at the end of their era for un-known reasons. Thereafter metazoans rapidly diversified and generated numbers of phylum-rank stem or crown lineages with different fates. The Cambrian explosion ultimately resulted in the critical transition from microbially-dominated ecosys-tems in the Precambrian to metazoan-dominated ecosystems in the Phanerozoic. However, the temporospatial pattern of eco-systems during the Cambrian explosion is poorly understood, largely because our current knowledge is biased in metazoan evolution and redox conditions, and thus insufficient to reconstruct an ecosystem that is an integrative entirety of biotic and abiotic components. Therefore, we proposed a facies-dependent integrative approach as a working hypothesis toward a more comprehensive understanding of ecosystem evolution during the Cambrian explosion.
    Abstract:
    In accordance with the cranidia structures, the method of “Q-mode cluster analysis” used in the present paper for a taxonomic study of 18 species of the genus Mufushania, that was established or adopted by Lin Tian-rui (1965), Li Shan-ji (1978),Zhang Wen-tang et al. (1980), Sun Zhen-hua (1982), Zhou Zhi-qiang et al. (1982), Guo Hong-jun et al. (1996), Yuan Jin-liang and Li Yue (1999), Peng Shan-chi et al. (2001), Yuan Jin-liang et al. (2002). The statistical measurement of similarity is incremental sum of error squares (ΔE). The use of the variability by the author is the eight quantitative ratio values (see table 1). The resemblance relation matrices of all specimens are formed through calculation of the increments of sum of error squares between those specimens (see table 2). These data show that M. shalangensis Zhang and Zhou in Zhang et al. 1980(5), M. angustilimbata Zhang and Zhou in Zhang et al.,1980 (7) and M. kailiensis (Yuan in Yuan et al., 2002) (13) species should not be a member of the Mufushania, not belonging to species of Mufushania. Finally, through the application of combined cluster analysis with traditional qualitative analysis in the study of fifteen species of Mufushania trilobites in this paper, of which M. changi Lin, 1965 (2) is regarded as a junior synonym of the type species (1) and M. zhanjiaxiangensis Sun, 1982 (10) is regarded as a junior synonym of M. ezhongensis Sun, 1982 (9), too, the other thirteen species of Mufushania in the opinion on lumping and transferring the studied species is proposed (see table 3).
    Abstract:
    The value of the discoveries of Hamipterus tianshanensis and their 3D eggs fossils?are of?great importance.?These fossils preserved in Beijing for several years, the surrounding rocks have been powdering and flaking, which seriously endanger the safety to fossils. This paper intends to use XRF and other methods to detect surrounding rock to explore its corrosion mechanism. The analysis shows that the surrounding rock of fossils is composed of sandstone with boulder clay, which contains some clay minerals such as montmorillonite. The?sandstone?with?calcareous?and?salt?cementation contains large amounts of soluble ions such as Cl-, NO3-, Na+ and Mg2+. The mechanism of the deterioration is as followed, when the humidity changes, the soluble salt also generates large crystal pressure, as well as the expansion of clay minerals produces huge pressing force, leading the surrounding rocks to powder and flake gradually. The?solution?of?salt?existing?as the cement results in the escape and?migration of?particles, which?is?an important reason for fossil deterioration.?Based on the above understanding, this paper also gives suggestions about the protection of fossils.
    Abstract:
    This study describes the Guadalupian (Middle Permian) fusulines from the northern Zhabuye area in the Lhasa Block and discusses their palaeobiogeography. In total, the fusuline fauna comprises 6 genera and 16 species, including Yangchienia tobleri Thompson, Yangchienia haydeni Thompson, Chusenella brevipola (Chen), C. schwagerinaeformis Sheng, C. cf. brevis (Chen), C. sp., Nankinella rarivoluta Wang, Sheng and Zhang, N. complanata Wang, Sheng and Zhang, Kahlerina tenuitheca Wang, Sheng and Zhang, K. pachytheca Kochansky-Devidé and Ramov?, Verbeekina americana Thompson, Wheeler and Danner, V. tenuispira Sheng, Neoschwagerina cheni Sheng, N. colaniae Ozawa, N. craticulifera (Schwager) and N. brevis Thompson, Wheeler and Danner. This fauna suggests a Wordian age, as evidenced by the presence of Kahlerina and the thick spirotheca and less-developed secondary transverse septula in Neoschwagerina species. The fauna from the Zhabuye area is correlatable with the contemporaneous faunas from other regions in the Lhasa Block including the Shiquanhe area, the Xiadong area in Tsochen County, Xainza County and Lhunzhub County. The synchronous appearances of Guadalupian warm-water fusuline faunas in the whole Lhasa Block exhibit a pronounced difference in palaeobiogeography from the Tethys Himalaya region with persistent cold-water brachiopod faunas during the middle and late Permian. It is unlikely that the Lhasa Block and the Tethya Himalaya region adjoined together before the late Triassic. Therefore, it is considered that the Lhasa Block has been separated from the Gondwanaland by Wordian time.
    Abstract:
    The Jurassic and Cretaceous strata in northern China are mostly of terrestrial origin. It presents a difficulty in defining the Jurassic-Cretaceous (J/K) boundary. In the previous biostratigraphic work, the J/K boundary was referred to a higher posi-tion of much younger age, which caused a big controversy between local biostratigraphy and the international standard. Re-cently, large quantity measurements of isotopic ages reveal that the J/K boundary is possibly within the Tuchengzi Formation. The formation is a group of terrestrial reddish sedimentary deposits, and divided into 3 members. It is the type sequence of terrestrial Jurassic-Cretaceous transition in northern China. The stratigraphic age of the formation is in disagreement, owing to more-or-less limited preservation of fossils and a contradiction between biostratigraphic and isotopic data. Certain fossil groups have been found in scattered beds, dominated by conchostracans, ostracodes, dinosaurs, spore and pollen. Further-more, the pronounced provincialism of the terrestrial fauna and flora obstructs global correlation. Paleontologists have al-ready produced many publications after hard work, and they gave different stratigraphic divisions. A large amount of isotopic dating provides reliable data showing that the duration of the Tuchengzi Formation is from 156 Ma to 139 Ma, covering the late Jurassic to early Cretaceous period. The J/K boundary lies within this interval. Huge chronostratigraphic data challenge the traditional biostratigraphic results. The chronostratigraphic unit, otherwise, has to be indicated by a biotic boundary marker. Before a biostratigraphic division of high precision has been worked out, we attempt to make an option for the J/K boundary marker according to the data in our possession. After recognizing the fossil assemblages, the location of the J/K boundary is between the Jurassic conchostracan Pseudograpta-Monilestheria-Sinograpta (P-M-S) and ostracode Cetacel-lasubstriata-Mantelliana alta-Darwinula bapanxiaensis (C-M-D) assemblages, and Cretaceous conchostracan Yanshano-leptestheria-Pingquania-Lingyuanella (Y-P-L) and ostracode Djungarica yangshulingensis-Mantelliana reniform-is-Stenestroemia yangshulingensis (D-M-S) assemblages. It is also indicated by the first appearance of spore and pollen Ci-catricosisporites-Lygodioisporites-Jiaohepollis (C-L-J) Assemblage. Lithologically, the boundary is between the members 2 and 3 of the Tuchengzi Formation and of ~145 Ma in age. The Batuying sections in Beipiao are recommended as the type sequence of the formation. Based on the occurrence of the earliest Cretaceous fossil assemblages in the member 3, we pro-pose a “Batuying Stage” as the lowermost terrestrial chronostratigraphic unit of the Cretaceous in China. The duration of the stage is 145–139 Ma, correlating roughly to the international Berriasian Stage. The members 1–2 are referred to the upper-most “5th stage” which approximately corresponds to the Kimmeridgian–Tithonian stages of the Upper Jurassic. The present suggestion is only to provide a consultation for the terrestrial Cretaceous chronostratigraphic study.
    Abstract:
    Trilobites are common fossil animals in the Cambrian. The fossil record of their healed exoskeletons can provide important information on the competitive arms-race relationship between trilobite prey and their potential predators in the Cambrian ecosystem. The early Cambrian Chengjiang biota from South China, well known for its exceptional fossil preservation, allows us to study the ancient ecological interactions in marine communities during the Cambrian explosion. However, there is no record of healed trilobites so far known from the Chengjiang biota. The trilobite Eoredlichia intermedia Lu, 1940, an index fossil of the second trilobite biozone in eastern Yunnan of China, is one of the commonest arthropods in the deposits. Of more than 2 000 specimens of E. intermedia in our collection, two adult specimens are revealed with deformities in the lateral margin of cephalon, genal spine, and the pleural region. We suggest that such injuries were most likely caused by unknown predators. The scalloped fractures or cracks on these two adult individuals were marginally thickened and smoothed at the edges, indicating obvious signs of healing. If interpreted exactly, these fossils lend some supports for the view that the victim Eoredlichia intermedia was capable of repairing their fractured exoskeletons from sub-lethal attack by unknown predators. Therefore, this research presents the thus-far oldest fossil record of trilobites with injuries and the first report of the trilobite exoskeleton with healed injuries from the Chengjiang biota, signifying an existing escalating arms race between durophagous predators and prey since Cambrian Stage 3.
    Abstract:
    Amber, as an organic gem, is fossilized natural resin widely distributed around the world, especially Baltic region in Europe, Dominica-Mexico in Central America, and Myanmar in Asia. Insects are the most common inclusions in amber, while verte-brate inclusions are the rarest. However, compared to vertebrate fossils from sedimentary rocks, vertebrate inclusions trapped in amber pieces can provide additional information about the soft tissues, primitive death states, and living environment, as well as more visualized and refined 3D morphological information, all of which are important for studies in evolution, palae-oenvironmental restoration, palaeoecology and palaeoethology, which is more intuitive, stereoscopic and detailed than bone fossils. This paper reviews vertebrate inclusions from various amber biotae, including non-avian dinosaurs, aves, mammals, reptiles and amphibians, as well as their evolutionary implication, and also provides a framework of future researches.
    Abstract:
    Ostracods are described for the first time from the Late Ordovician in Nyalam, southern Xizang (Tibet), China. Thirty species belonging to sixteen genera are described and figured from the Jiaqu Formation in the Yalai Waterworks section. The ostracod fauna suggests a probable Sandbian-Katian Age for the Jiaqu Formation. The ecological assemblage of ostracods fauna belongs to the Eifelian Ecotype, which implies a nearshore depositional environment for the Jiaqu Formation. In the diverse ostracod fauna of the Jiaqu Formation, many cosmopolitan or provincial genera are shared in Himalaya, Tarim and South China, suggesting a close biogeographic relationship for the blocks.
    Abstract:
    The Renyi Section is a newly discovered section in the vicinity of Renyi Town, Hezhou City of Guangxi, in which a continuous marine sedimentary succession of the Middle and Upper Devonian is well developed and out-cropped. The succession yields abundant benthic and pelagic fossils. This paper presents a preliminary research resulton the conodonts and brachiopods from the middle part of the Middle-Upper Devonian Baqi Formation (ca. 80 m thick) at this section. Ten species (or subspecies) of three genera of conodonts are recognized from the studied interval, including Polygnathus alatus, P. cf. collieri, P. cristatus, P. dubius, P. dengleri, P. dengleri sagitta, P. webbi, P. xylus, Klapperina disparalvea and Schmidtognathus wittekindti. Seventeen species of 16 genera of brachiopods are also reported herein, including Schizophoria sp., Gypidula sp., productoid gen. et sp. indet., Leiorhynchus kwangsiensis, Coeloterorhynchus sp., Hypothyridina sp., Uncinulus? sp., Fitzroyella sp., “Ypsilorhychus” subellipticus, Desquamatia sp., Spinatrypina douvillii, Spinatrypina sp., Emanuella sp., Mucrospirifer sp., Undispiriferoides tianqipuensis, Cryptonella? sp. and Oligothyrina? sp. According to the distribution of the conodonts, three conodont zones (S. hermanni, P. cristatus and K. disparilis zones) have been recognized from the studied interval, suggesting an age of late Givetian of the Middle Devonian. The brachiopods were mainly collected from two fossiliferous layers near the base and top of the studied interval, representing two different brachiopod assemblages. The brachiopod fauna from the lower fossiliferous layer (ca. 20 cm thick, S. hermanni Zone) is relatively monotonous in composition, mainly consisting of L. kwangsiensis. This finding verifies the Middle Devonian occurrence of the genus Leiorhynchus in South China. The upper fossiliferous layer (ca. 3 m, upper K. disparilis subzone) yields a diverse brachiopod fauna, including at least 15 genera and displaying the highest diversity of brachiopods ever recorded in a single fossiliferous bed from the upper Givetian of South China.
    Abstract:
    A new genus and species, Ayaimatum trilobatum gen. et sp. nov. Jiang and Szwedo, is described based on a planthopper preserved in mid-Cretaceous amber from Kachin State, northern Myanmar, and assigned to the Cretaceous planthopper fam-ily Mimarachnidae. A short overview of fossil record of the Mimarachnidae is given. The taxonomic diversity and morpho-logical disparity of this extinct group is briefly discussed.
    Abstract:
    Re-examination of the holotype specimen of the clam shrimp type species Loxomegaglypta wetlugiana Novojilov, 1958 us-ing a scanning electron microscope (SEM) has revealed details of carapace features with important taxonomic value, which have never been described hitherto. The new features include: growth bands in the middle and ventral part of the carapace are ornamented with circular, angular or elliptical sieve-like fine pits (15 to 25 μm in diameter), which are surrounded by vari-ously shaped, wide swellings. Puncta (4 to 6 μm in diameter) occur not only in the pits, but also on the surrounding swell-ings. This ornamentation pattern is different from the originally described angular reticulation, and thus the diagnosis of Loxomegaglypta is emended.
    Abstract:
    This paper briefly summarizes the history of amber research in China and introduces the content of this special issue. The special issue includes 13 papers of 26 authors in 14 universities or institutes and covers some new progresses about plants, vertebrates, gastropods, and insects in mid-Cretaceous Kachin amber biota.
    Abstract:
    Up to now, little is known about the palaeovegetation of the most northeastern part of the great Qinghai-Xizang (Tibet) Plateau during the Neogene time. In this study, we report Miocene pollen and spore assemblages from the Maladun Formation at Hongtupo, a small mountain about 50 km southwest of Songpan County town, Sichuan Province. The palynoflora is characterized by rich presence of Ulmaceae, Betulaceae and abundant Pinaceae pollen with rare spores. Angiosperm pollen occupies 52.9%–84.4% of the total tally. Gymnosperm pollen form 13.8%–44.1% of total pollen and spores. Spores only amount to 1.9%–5.1% of the total assemblage. Other elements in the pollen flora include common Fagaceae (Quercus, Castanea), Salix, Juglandaceae (Juglans, Carya) and minor Liquidambar, Sporotrapoidites, Lonicera, Ephedra, Compositae (Asteraceae), Rosaceae, Leguminosae (Fabaceae), Polygonaceae, Ranunculaceae, Lythraceae etc. Such a pollen flora represents a mixed broadleaved and conifer forest. The pollen flora of the Hongtupo is of late Early Miocene to early Middle-Miocene age based on the correlation with the similar pollen assemblage from the Lengshuigou Formation of Weihe Basin which was dated by the associated vertebrate fossils. The palaeoclimate derived from the pollen flora should be of cold temperate to temperate with an annual temperature of about 8℃–13℃. The present pollen flora shows a much less warm appearance than those of the similar age pollen floras from northern and eastern China, which leads to a deduction of palaeoaltitude at the fossil locality of over 1000 m to about 2000 m above sea level. It is interesting that the pollen flora also contains some warm-loving elements such as Liquidambar and Juglandaceae pollen, which probably implies the Miocene Hongtupo area was neighbored by a low terrace or valley landscape.
    Abstract:
    Thalattosaurs are one of the three major groups of top reptilian predators in the Triassic marine ecosystems, the study of which is a key to our understanding of biotic recovery from the Permo-Triassic mass extinction. Significant advancement has been achieved in the last decades in studying biodiversity and phylogeny of Thalattosaurs. However, the origin of Thalatto-saurs and the process forming the biogeographical pattern of Thalattosaurs largely remains an enigma. We review here the recent progress in the study of Thalattosaurs in terms of its origin, species diversity, phylogeny and biogeography. Our re-view shows that large gap exists in the research of Thalattosaurs. Future research should be focused on field work in the early part of the Triassic strata to search for more primitive Thalattosaurs. This is necessary to elucidate its origin. A first-hand systematic review of Thalattosaurs from SW China should be performed to clarify the true biodiversity of Thalat-tosaurs, which is also a basis for a comprehensive phylogenetic analysis of thalattosaurian relationships. Finally, the study of the physiology and paleoecology of Thalattosaurs via the investigation of long bone histology and microanatomy is of great significance in establishing the process forming the biogeographical pattern of Thalattosaurs.
    Abstract:
    40 years ago, the 3rd National Congress and the 12th Annual Conference of the Palaeontological Society of China was held in Suzhou of Jiangsu Province. The Congress has historical significance in the Chinese palaeontological development. Since 1979 the Chinese palaeontological research entered a new developmental stage, with excellent achievements springing up in large numbers, and frequent academic exchanges occurring. In the following years, the activities of the Society were more active than ever before, significant increase in membership, the activities of society had regularized. The Chinese paleontologists have returned to the international community with frequent exchanges.
    Abstract:
    The stonefly fauna in mid-Cretaceous Burmese amber is reviewed. A new fossil stonefly, Burperla decolorata gen. et sp. nov., is described and illustrated based on a well-preserved female specimen. This new taxon is characterized by the combi-nation of the following characters: long and pale body, long palps and antennae, RA almost reaching wing apex, subgenital plate broad and rounded with a posteromedial projection. These morphological characters distinguish it from other extant and extinct stoneflies of Perlidae.
    Abstract:
    A new species, Stavba vrsanskyi sp. nov., is established and attributed to the family Liberiblattinidae on the basis of a blat-tarian specimen from mid-Cretaceous Burmese amber. The new specie differs from Stavba babkaeva Vr?anská and Vr?ansky, 2019 in the following characteristics: triangular head shape, R of forewing without secondary branches and less M. This new find provides novel biology diversity in Blattaria in mid-Cretaceous Burmese amber.
    Abstract:
    Burmese amber contains one of the most diverse amber biotas all around the world. The geological age for Burmese amber is about 98.8 Ma, which was widely accepted as mid-Cretaceous. The Burmese amber biota provides an important window for us to seek the biodiversity and palaeoecology of the ancient world. Here, based on the study of stratigraphy and palaeobiolo-gy, palaeoenvironment and the deductions of the insect behavioral ecology proposed by numerous authors are comprehen-sively reviewed. These fields refer to co-evolution of insect and plant, predation, eusocial evidence, parasitism, courtship be-havior and structural coloration, provide us a more comprehensive summary of palaeoecology and insect behavioral ecology in Burmese amber.


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