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    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2021062
    Abstract:
    Total 19 drilling cores from the Upper Ordovician Lianglitag Formation in Lunnan Oil Field of northern Tarim Block are analyzed as limestone-dominated sequences in a westward deeping ramp of epicontinental sea. Calcimicrobes of the Renalcis, Girvanella,Wetheredella,Garwoodia,Phacelophyton yushanensis,Hedstroemia?and Halysis;calcareous algae of the Vermiporella, Dasyporella, Plexavaria,Solenopora as well as metazoan fauna of the sponge, coral, bryozoan, trilobite, brachiopod, echiodermata, gastropod, ostracoda are of the roles of the biotic components in diverse bioclastic limestones. Palaeoecological correlations along wells show that western ramp was favorable for growth of reefs and lime mudmound. Intra-platform in the eastern part is dominated by diverse intra-clastic banks. Seascape changes with westward deeper marine-floor are considered as the key roles in configurations of the temporal and spatial distribution patterns of the ecological associations.
    Available online:March 31, 2023, DOI:
    Abstract:
    按照中国古生物学会2023年工作计划和十二届五次理事会议关于开展“中国古生物学年度十大进展”评选活动的决定, 我会开展了2022年度中国古生物学十大进展的推荐和评选工作。提名推荐阶段学会秘书处共收到理事和分支机构推荐的提名成果31项。
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2021051
    Abstract:
    Helcionellids are common mollusks of the Cambrian. They occur in Cambrian strata all over the world, but they are mostly found in carbonate depositional settings and rarely reported in Burgess Shale-type faunas. The Kaili biota in Jianhe, Guizhou Province is a typical exceptionally preserved fossil Lagerst?tten, where more than 700 specimens of helcionellids were collected, which is particularly noteworthy among Cambrian Burgess Shale-type faunas. Herein, helcionelloid mollusks from the Kaili biota were analyzed by using canonical variate analysis (CVA) of the geometric morphological method. Geometric morphometrics refers to a quantitative analysis of organism morphology and specific marked parts. As an important method for multivariate analysis, CVA can be used to discriminate differences between data sets. Results of CVA show that, by analyzing the lateral outline of Dorispira, the accuracy rate of identifying the three species Dorispira accordinonata, Dorispira taijiangensis, and Dorispira cf. pearylandica was 92 %, which accords with morph-based classifications of the genus. This work demonstrates that CVA can be used to quantify the differences between species with relatively similar morphologies, thus providing a quantitative reference for the application of geometric morphometry in systematic paleontological taxonomic studies.
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2022036
    Abstract:
    Calcareous fossils from the middle-upper part of the Weiba Formation (grainstone) at Dagala, Zhenxiong County, northeastern Yunnan have been extensively silicified and are extracted through glacial acetic acid (5-12%) dissolution, after high temperature deacidification from carbonate matrix. More than 2000 specimens are obtained (Fig. 1). The Weiba Formation is conformably overlain by the Lungmachi Formation (Rhuddanian) and is disconformably underlain by the Daduhe Formation (upper Katian). The basal part of the Lungmachi Formation yields graptolites suggesting the Akidograptus ascensus Biozone. Thus, the Weiba Formation is postulated to be late Hirnantian in age (Wang et al., 2022). The brachiopods dominate the benthic biota, making up approximately 95% of all specimens in this formation (Fig. 2). A preliminary investigation of the silicified brachiopods is herein presented for the first time. Based on this study, more than 20 taxa are recognized, including Eospirigerina putilla (Hall and Clarke) (predominant), Hesperorthis, Dalmanella (relatively common), Cathaysiorthis, Mendacella, Epitomyonia, Brevilamnulella, Hindella (rare), along with Paracraniops, Fardenia, Triplesia, Leptaena, Eostropheodonta, Eoplectodonta, Platystrophia, Glyptorthis, Thebesia, Hallina? and Eospiirier (very or extremely rare), as well as a few undetermined taxa of orthide, rhynchonellide and atrypide (Figs 3, 4). These taxa belong to 9 orders, 15 superfamilies, and 20 families, suggesting a relatively abundant and highly diverse brachiopod assemblage established in the soon aftermath directly following the Late Ordovician mass extinction (LOME), representing far more genera than expected. Extensive groups of marine benthic organisms are associcated with the brachiopods that signify both autotropic and heterotrophic organisms, including calcareous algae, bryozoans, crinoids, gastropods, rugose corals, stromatoporoids (sponges), tabulates (auloporids and halysitids), tube worms (such as Cornulites), and a few others. Hence, evidence indicates that diversity of the overall biota living in a shallow-marine setting was relatively high immediately after the LOME in South China. In terms of the palaeosynecology, the brachiopods studied in this paper are designated as members of the Eospirigerina putilla Community. It may have occupied a near-shore, shallow, well-oxygenated water environment, and is assigned to upper Benthic Assemblage 3. Herein, this community of late Hirnantian age is compared with a similar Dalmanella-Plectothyrella Community of the early-middle Hirnantian Hirnantia Fauna from nearby Bijie and Renhuai counties, in northwestern Guizhou (Rong and Li, 1999). The comparison shows that there occur significant differences in many aspects. The Dalmanella-Plectothyrella Community registers a low diversity, which followed after a disaster crisis during the first phase of the LOME (Fig. 5). Numerous declining genera (including their extreme type, Lazarus taxa), such as Hesperorthis, Glyptorthis, Platystrophia, Katastrophomena, Eospirigerina during the crisis, were common in the late Katian and recovered in the late Hirnantian. They became a symbol of brachiopod survival and recovery during the early Silurian (Figs 6 and 7). The Eospirigerina putilla Community is found to be related to the brachiopods from upper Hirnantian-Rhuddanian rocks occurring in the Meitan, Zunyi and Shiqian counties of northern Guizhou, Southwest China (Rong, 1979; Rong et al., 2011) and Yushan County of northeastern Jiangxi, as well as the Jiangshan and Chun’an counties of western Zhejiang, East China (Rong and Zhan, 2006; Rong et al., 2008, 2013; Huang, 2008) (Fig. 8). These brachiopods previously were named the Cathaysiorthis Fauna (Rong and Zhan, 2006; Huang, 2008; Rong et al., 2013; Huang et al., 2019), and later the Edgewood-Cathay Fauna in the light of a combination of both the Edgewood Fauna typically developed in Mid-Continent of USA (Amsden, 1974) and the Cathaysiorthis Fauna in Zhe-Gan border area, East China in latest Ordovician and earliest Silurian (Rong et al., 2020). The Edgewood-Cathay Fauna is known from the uppermost Ordovician and Rhuddanian rocks in the North American Mid-Continent (Amsden, 1974), Manitoulin, East Canada (Stott and Jin, 2007), Sweden (Jin and Bergstr?m, 2010), southern and central Norway (Cocks, 1982; Heath and Owen, 1991; Baarli, 2019, 2021, 2022), Kolyma, Russia (Koren et al., 1983), Chingiz of Kazakhstan (Nikitina et al., 2015), Gorny-Altai (Kulkov and Severgina, 1987), and Tasmania, Australia (Laurie, 1991). It is noteworthy that in aspects of lateral profile, ornamentation, muscle fields of both valves, and cardinalia, Hirnantia enorme Laurie, 1991 from lower Westfield Sandstone in Tasmania is attributed to the genus Cathaysiorthis because it was thought to be very similar to Cathaysiorthis yushanensis (Zeng and Hu, 1997) (Rong et al., 2013). It is likely that a close paleobiogeographic relationship existed between South China and Tasmania, judging from the presence of Cathaysiorthis. A recently proposed new term, “Cathay-Tasman Province” shows similar recognition of a faunal province in view of the Ordovician brachiopods and trilobites (Cocks and Torsvik, 2021), suggesting an extension of a faunal relationship shared between the two regions through the LOME. The strata yielding the Edgewood-Cathay Fauna in South China are generally underlain by Katian rocks with the absence of the typical Hirnantia Fauna and the presence of a disconformity in between, as recorded in Mid-Continent, North America (Amsden, 1974, Bergstr?m et al., 2012a, b). The two phenomena as narrated above may have been consistent with a dramatic global sea-level lowering starting in terminal Katian time (the first episode of the LOME) and a substantial post-glacial sea-level rising in the late Hirnantian (the second episode) (Fig. 9). Comparison of the Hirnantia Fauna and the Edgewood-Cathay Fauna indicates significant differences in taxonomic composition, biodiversity, predominance, ecological differentiation, biogeography and their symbionts. The major faunal turnover during the late Hirnantian occurred not only in shallow-water, but also in deep-water environments. This suggests an evolutionary process of early Paleozoic brachiopods and their concomitants subjected to cataclysmic shocks (Fig. 10). As supplemented by new data from this paper and based on the data of Rong et al. (2020), the global occurrences of the Edgewood-Cathay Fauna are shown in Fig. 11. During the time interval between the two episodes of the LOME, the absence of many warm-preference benthic genera (e.g., tabulates, stromatoporoids, and some bryozoans) (Wang et al., 2018; Jeon et al., 2021 Zhang et al., 2018; Ma et al., 2022), the extreme poverty of conodonts (Zhang and Barnes, 2004; Wang, 2013), and nearly disappearances or absence of warm-preference brachiopods (e.g., pentamerides, atrypides, or trimerellides respectively) in South China are in accordance with the data from carbon and oxygen isotopes in North America and elsewhere (Finnegan et al., 2011; Bergstr?m et al., 2019) (Fig. 12). Turnover of the Hirnantian brachiopod faunas has been thought to have been controlled by the coincidence of major perturbations, particularly the intensification of a deteriorating climate (Harper et al., 2014). Major changes of marine surface water temperature may have been one of the negative influences on shallower-water brachiopods and widespread anoxia for deeper-water brachiopods (e.g., Aegiromenella). When the second episode came, brachiopods with a preference for colder water (e.g., Hirnantia, Kinnella, Paromalomena, Draborthis, Dysprosorthis, Trucizetina) were unable to migrate in time into shallow, well-oxygenated, relatively warm-water, into to avoid widespread anoxic environments, whereas many taxa of the Edgewood-Cathay Fauna, mostly eurytopic ones (e.g., Hesperorthis, Glyptorthis, Brevilamnulella, Stegerhynchus, Eospirigerina, Eospirifer), along with those eurytopic taxa from the Hirnantia Fauna (e.g., Dalmanella, Cliftonia, Fardenia, Hindella, Leptaena, Triplesia) did so in order to survive in the then near-shore waters of the late Hirnnatian-Rhuddanian (Fig. 13). The Akidograptus ascensus Biozone has been ratified as the basal biozone of the Silurian System (Melchin and Williams, 2000; Rong et al., 2006), recognized mainly in graptolitic facies with black shales. Meanwhile, it is possible to roughly delimit the O-S boundary in shelly facies but difficult to define precisely, particularly as bio-and chemo-stratigraphical data are insufficient or contradictory. The investigation in this paper demonstrates that the replacement of the Hirnantia and Edgewood-Cathay faunas in the late Hirnantian, indicating LOME ended slightly before the O-S boundary, as recorded by Stott and Jin (2007).
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2022019
    Abstract:
    Abstract Phycosiphon is abundant and well preserved in the middle portion of Daye Formation in Huaxi district of Guiyang in Early Triassic, which provides good materials for studying its ecological behavior and morphological structure. The Phycosiphon burrow system of Daye Formation is composed of "U"-shaped leaf-shaped pascichnia and linear repichnia. Statistical analysis of width, height and edge tube diameter of 267 "U" leaves in 61 samples shows that the ratio of width to height of "U" leaves ranges generally from 50% to 60%, and the ratio of edge tube diameter to leaf height ranges from 12% to 18%. Combined with linear correlation analysis, it is considered that there is a certain relationship between Phycosiphon trace maker size and leaf size; through the analysis on the behavior of Phycosiphon trace makers, it is considered that the concave direction of leaves can indicate the foraging direction of Phycosiphon trace makers. In morphology, "U"-shaped pascichnia and linear repichnia can form 4 combined types: antler- shape, mass-shape, irregular-shape and chain-shape. Antler- shape and mass-shape are mostly formed in front of turbidity flow, indicating low-energy still water environment; irregular-shape is generally formed after turbidity current, indicating water environment with high deposition rate and relatively high energy; However, chain-shape develops in both environments, which reflects the random foraging characteristics of Phycosiphon trace makers. The early Triassic study area is located in the slope of shallow sea peri-platform slope, with frequent turbidity current, and the whole area is in an oxygen-poor and low-energy environment. The development of Phycosiphon in the second member of Daye Formation is one of the characteristics of "anachronistic facies" after P-T event.
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2022017
    Abstract:
    Hyoliths were one of the prominent components of the Cambrian small shelly fossil assemblage on the North China Block, and witnessed the explosive radiation of animal life in North China. Here fourteen species and one undetermined species assigned to nine genera of the Hyolitha were systematically described from the Cambrian Series 2 Xinji Formation along the south-southwestern margin of the plate. This hyolith fauna yields six orthothecid genera and nine species: Conotheca australiensis, Cupitheca holocyclata, Cupitheca costellata, Cupitheca? decollata, Tegminites hymenodes, Triplicatella disdoma, Triplicatella xinjia, Protomicrocornus triplicensis, Longxiantheca mira; three hyolithid genera and five species and one undetermined species: Microcornus eximius, Microcornus petilus, Parkula cf. esmeraldina, Parkula bounites, Parakorilithes mammillatus, Parakorilithes sp. Based on abundant well-preserved articulated specimens of this assemblage, we provided a complete reconstruction of the hyolith skeletons (conch-operculum). In addition, more than half of studied hyolith species in North China possessed transverse septa of their conch. Of these, septa in Conotheca and Longxiantheca can effectively strengthen and further seal off the apical end of the conch, and are used for decollation during growth of the conch in Cupitheca and Microcornus. Moreover, Parakorilithes and Protomicrocornus conchs develop single and multiple septa respectively, which could largely avoid penetration of soft tissues into the conical shells. According to these observations, we propose that the presence of teeth-like structures of operculum, septa and unique decollating growth mode of conch can significantly enhance the sealing of the conch by associated operculum, and improve adaptability of calcareous exoskeletons to marine substrate environments. Meanwhile, the tentacle-bearing feature of soft tissues is functioned as suspension-scavenging-detritus feeding apparatus and adapted to a wide spectrum of niches. These survival strategies and evolutionary adaptability may be one of the important reasons for the rapid diversification and thrive of hyoliths in the Cambrian ocean.
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2022012
    Abstract:
    Chaohu Fauna fossils are mainly distributed in the Middle and Upper Member of Nanlinghu Formation of Olenekian (Lower Triassic) in Chaohu and its adjacent regions, Anhui Province. It is characterized by a composition of abundant well-preserved Chaohusaurus along with sauropterygian, ichthyosauroformes and multiple groups of marine invertebrates. The study on Chaohu Fauna first started in the 1970s. Recently, the comprehensive research on the new material of Chaohu Fauna has provided new evidence for the rapid recovery of Triassic marine ecosystem after the end Permian mass extinction. This paper reviews the progress on the Chaohu Fauna regarding the geological setting, research history, fossil assemblage composition, bio- and chronostratigraphy and stable isotopic geochemistry, and provides a brief discussion on the paleoecology. This work is significant in promoting the construction of Chaohu Fauna related National Geopark, science popularization education and tourism development.
    Available online:March 31, 2023, DOI: 10.19800/j.cnki.aps.2022054
    Abstract:
    Leptephialtites Rasnitsyn, 1975 is a diverse wasp genus of the subfamily Ephialtitinae (Ephialtitidae) in the Late Jurassic Karatau Biota from Karatau, southern Kazakhstan. It was also reported from the Middle-Late Jurassic Daohugou Biota in Ningcheng, northeastern China but no descriptions and figures had been provided. Herein, a new species is established and assigned to this genus as Leptephialtites zhangi Ding and Zhang, sp. nov. based on a female wasp from the Middle-Upper Jurassic Daohugou Beds at Daohugou Village, Wuhua Town, Ningcheng County, Chifeng City, Inner Mongolia, China. The new species shows some differences from the Karatau species in having a forewing with 1-Rs about half length of its distance to pterostigma (vs. at most as long as its distance to pterostigma) and 1r-rs complete (vs. rudimentary or completely absent), and a spindle-like metasoma broadest medially (vs. broadest in rear half). Furthermore, a key to the species of Leptephialtites is provided. Occurrence of the genus Leptephialtites in both the Karatau and Daohugou biotas confirms the close relationship between the two biotas.
    Available online:March 29, 2023, DOI: 10.19800/j.cnki.aps.2022022
    Abstract:
    The Yumidong is a Paleolithic cave site discovered in Miaoyu Basin of Wushan County, Chongqing Municipality, Southwest China. The background, lithostratigraphic section and dating results of this site have been described, and the comprehensive analysis of dating results and faunal comparison shows an age of late Middle to Late Pleistocene for the site, about 300 ka to 14 ka, corresponding to MIS 8~2. Many cervid fossils have been unearthed from this site, which provide pretty good materials for the morphological comparisons of Cervidae in the Middle to Late Pleistocene of South China. Three genera and species have been recognized, including Muntiacus muntjak margae, Rusa unicolor and Cervus (Sika) grayi. M. m. margae is only found from the late Middle Pleistocene deposit in the Yumidong Site, having similar size with M. gigas but shorter main beam and longer brow tine than the latter. R. unicolor is larger than C. (S.) grayi, and its antler is robust with well developed longitudinal grooves and crests on the surface. The bifurcation angle between brow tine and main beam is acute. C. (S.) grayi is somewhat slender, and the surface of its antler is ornamented with shallow longitudinal grooves. The bifurcation angle between brow tine and main beam is obtuse. M. m. margae and R. unicolor are both the most common taxa in the Middle to Late Pleistocene mammalian fauna of South China, but C. (S.) grayi is known as a typical Middle Pleistocene species of North China, even it was also found from some Late Pleistocene localities in East China and Japanese archipelago. In term of stratigraphic distributions, specimens of R. unicolor were unearthed from most layers of the deposit in the Yumidong Site, but C. (S.) grayi was only found from limited layers that can be corresponded to MIS 2, MIS 6 and MIS 8. The presence of C. (S.) grayi indicates paleoenvironmental fluctuation during the late Middle to Late Pleistocene in the Three Gorges area.
    Available online:March 29, 2023, DOI: 10.19800/j.cnki.aps.2021073
    Abstract:
    Halkieria is a kind of Cambrian problematic metazoan with mineralized sclerites covering its body. It possesses a large shell plate on both anterior and posterior parts of the body, and its calcareous sclerites are arranged bilaterially-symmetrically, which form several regular longitudinal bands on the body. For over half a century, the biological affinities of Halkieria or halkieriids have been contentious. This paper summarizes the research progress of Halkieria fossils in aspects of taxonomy, paleogeographical distribution, stratum spanning, and reviews the following viewpoints regarding its biological affinities: 1) Halkieria is a stem group brachiopod, and has a close relationship with tommotiids; 2) The sclerites fossils such as Halkieria and Wiwaxia are monogenic, forming a monophyletic lineage, Halwaxiidae, which belongs to a stem group mollusk or brachiopod and annelid; 3) Halkieria is a stem group of the Aculifera, that includes the class Polyplacophora and Aplacophora; 4) Halkieria is the ancestor of annelids. Of these, it is currently widely accepted that Halkieria is a stem group aculiferan because of the close comparability of scleritome construction between Halkieria and chitons, which, however has been challenged by new fossil materials discovered across the globe and ontogenetic studies of the animal. Through systematical determination of taxonomy and summary of research progress in biological affinities. The paper further discusses the significance of Halkieria in the taxonomy of SSFs, reconstruction of scleritome, origin and evolution of lophotrochozoans. And we further point out the deficiencies of current studies of Halkieria and highlight the research emphasis in future.
    Available online:March 27, 2023, DOI: 10.19800/j.cnki.aps.2021060
    Abstract:
    The Cambrian Kaili Formation in Jianhe, Guizhou province yielded abundant hyolitha fossils, among which Haplophrentis carinatus accounted for the largest proportion and was the most well-preserved. Previous researches on Haplophrentis carinatus were merely limited to taxonomy, lacking further discussion on the taphonomic features of Haplophrentis carinatus and its symbiotic relationship with other organisms. Herein, we conducted a systematic research on 324 specimens of Haplophrentis carinatus. Four taphonomic modes of opercula were recognized: separately preserved opercula, internal or external molds of opercula, partially and completely?articulated opercula. Few helens were preserved and conchs were mainly preserved as internal molds. In addition, a trident-like structure occurring on internal molds or fossil impressions, which resembles soft-tissue preservation, was taphonomic artifacts. The symbiotic relationship between Haplophrentis carinatus and eocrinids was also discussed and treated as an amensalism.
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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:
      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:
      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:
      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:
      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:
      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:
      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.
      [PDF 4.04 M] (2482)
      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.
      [PDF 4.51 M] (2412)
      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:
      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.
      [PDF 2.29 M] (2395)
      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:
      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.
      [PDF 3.84 M] (2343)
      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:
      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.
      [PDF 5.43 M] (2248)
      Abstract:
      Brachiopods are a group of lophotrochozoan animals, which have a long geological range from the Cambrian to Recent and a considerable geographical distribution in Paleozoic marine environments. Most rhynchonelliformean brachiopod shells are composed of calcite, and preserved in different kinds of sedimentary rocks (e.g. limestone, dolomite, siltstone, mudstone, and shale). An improved technique of acid digestion for extracting weakly-silicified brachiopod fossils from limestone is intro-duced here. This method includes a series of processes, i.e. preparing samples (fresh rock samples cut into cuboid pieces of 40 ? 20 ? 20 cm3 approximately), suspending samples (samples suspended in an acid-resistant container by wire), making an ethanoic acid solution (the concentration of the acetic acid within the range of 0.5%–3% in volume), etching samples (a series of procedures involved to keep acid solution effective for etching samples but harmless to brachiopod shells), and brushing mask liquid (cellulose acetate solution involved here to mask shells from acid etching). This method is effective in extracting weakly-silicified brachiopod fossils from limestone, and is applicable for extract-ing other kinds of fossils with similar preservation. However, this method is time-consuming and complicated compared with the classic acid technique. Sample processing may take two to four months, depending on the host-rock lithology, concentra-tion of the acetic acid solution, and the ambient temperature of acid digestion lab. This improved technique yielded many intact, weakly-silicified, and well-preserved brachiopod fossils with delicate car-dinal process and dental plates, extracted from the upper part of the Tiezufeike Formation (Upper Ordovician) of the Wandunshan section, Butuo County, Sichuan Province. Some of them were photographed under an optical microscope without physical modification and presented here as examples.
      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:
      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.
      [PDF 1.66 M] (2081)
      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:
      The Cretaceous is a period of frequent occurrence of major geological events such as oceanic anoxia and biological extinction, and also an important period of global warming. Therefore, the study of the Cretaceous is of great significance to the study of the systematic evolution of the earth in geological history, especially the co-evolution relationship between organisms and environment. The complete stratigraphic sequence of the Upper Cretaceous is preserved in Gongza, Tingri, Tibet. In this paper, well-preserved planktic foraminiferal fossils obtained from the samples of the Gangba Cunkou Formation and Zongshan Formation of the Upper Cretaceous are studied, and 22 species of 8 planktic foraminiferal genera are identified. Four foraminiferal zones are recognized as follows, from bottom to top: Dicarinella asymetrica, Globotruncanita elevata, Globotruncana ventricosa, and Radotruncana calcarata. According to foraminifera fossils, the age of Upper Cretaceous strata of Gongza section should be from the late Cretaceous Santonian-Campanian, and the Santonian/Campanian boundary should be located at the boundary between the Dicarinella asymetrica Zone and the Globotruncanita elevata Zone.


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