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三叶虫是寒武纪演化动物群中最引人注目的成员之一,其内部解剖结构一直以来受到广泛关注.与其他非生物矿化软体结构相比,三叶虫的消化系统更容易留下化石记录,为探索其内部结构提供了难得的机会.本文描述了来自山东省潍坊市寒武系馒头组的Proasaphiscus,Lioparia,Deiradonyx和Iranoleesia,以及...  相似文献   

3.
Numerous macro-organisms of the Doushantuo macrobiota, which were found in the black carbonaceous mudstone of the upper Neoproterozoic Ediacraan Doushan-tuo Formation in Jiangkou County, Guizhou Province, China, are considered to live on sea floor by their holdfasts. The appearance and preserved forms of the macroalgal holdfasts may provide some data to the study of the living and buried environments ofmacrobiota. They lived in the lower energy and clear environment, and fixed on a soupground with rich water (about 79% water). Currents, possibly ocean currents, could pull out the macroalgal holdfasts from the soupground and break off the macroalgal foliations. After such events, the corpses of macro-organisms would be covered in a reduced environment by the deposits. Afterwards, a new community, including regenerating and undying macro-organisms, lived continuously on a new deposit.  相似文献   

4.
Numerous macro-organisms of the Doushantuo macrobiota, which were found in the black carbonaceous mudstone of the upper Neoproterozoic Ediacraan Doushantuo Formation in Jiangkou County, Guizhou Province, China, are considered to live on sea floor by their holdfasts. The appearance and preserved forms of the macroalgal holdfasts may provide some data to the study of the living and buried environments of macrobiota. They lived in the lower energy and clear environment, and fixed on a soupground with rich water (about 79 water). Currents, possibly ocean currents, could pull out the macroalgal holdfasts from the soupground and break off the macroalgal foliations. After such events, the corpses of macro-organisms would be covered in a reduced environment by the deposits. Afterwards, a new community, including regenerating and undying macro-organisms, lived continuously on a new deposit. __________ Translated from Acta Micropalaeontologica Sinica, 2005, 23(2): 154-C164 [译自: 微体古生物学报]  相似文献   

5.
A partial skeleton of a new pterosaur, Jianchangnathus robustus gen. et sp. nov. from western Liaoning, China, is described. The specimen (IVPP V16866) was collected near Linglongta, Jianchang County, whose deposits have a disputed age that range from Middle Jurassic to Early Cretaceous. The new species shares several features with the non-pterodactyloid Scaphognathus from the Late Jurassic deposits of southern Germany, such as a deep anterior end of the lower jaw, a piriform lower temporal fenestra with the ventral margin broader than the dorsal one and the interalveolar spacing of the maxillary teeth about three alveolar spaces, allowing its allocation to the Scaphognathidae. The main diagnostic features of J. robustus include the large maxillary process of the jugal, the convex alveolar margin of the lower jaw and the procumbent disposition of the first three pairs of dentary teeth. The new Chinese taxon also differs from Fenghuangopterus lii, which comes from the same deposit and is here regarded as Scaphognathidae incertae sedis, mainly by the lower number of teeth and several proportions of the wing elements. The discovery of J. robustus demonstrates a larger diversity in the pterosaur fauna of the Linglongta region so far dominated by the non-pterodactyloid clade Wukongopteridae.  相似文献   

6.
A new specimen of Philydrosaurus proseilus from the Early Cretaceous Chiufotang (Jiufotang) Formation preserves the first complete palate of a monjurosuchid choristodere. As in other choristoderes, the palate of Philydrosaurus is akinetic, extended by a broad contact between the vomer and maxilla, and equipped with multiple batteries of palatal teeth. This specimen provides phylogenetically significant information and clarifies the distribution of many apomorphies within Choristodera. Philydrosaurus is primitive relative to the Neochoristodera in that it exhibits only a moderate degree of posterior displacement of the choanae and retains a relatively large interpterygoid vacuity. However, Philydrosaurus also exhibits several derived features previously considered diagnostic of the Neochoristodera, including establishment of a long midline contact of the pterygoids and development of a distinct nasopalatal trough extending from the choana. The choristodere palate exhibits significant modification of the primitive diapsid condition, including elongation of the vomers, establishment of a vomer–maxilla contact, posterior displacement of the choanae, development of the nasopalatal trough, and reduction of the interpterygoid vacuity.  相似文献   

7.
Early Miocene vegetation and climate in Weichang District, North China   总被引:1,自引:0,他引:1  
The Early Miocene palynological assemblage of Guangfayong (GFY) in the Weichang District, Hebei Province, China has been studied. It consists of 48 palynomorphs belonging to 39 families, with pollen and spores belonging to angiosperms (28.9%), gymnosperms (59.9%), ferns (10.8%) and other elements (0.5%). Based on the palynological assemblages of GFY and Wuluogong (WLG), another locality in the Weichang District, the Early Miocene vegetation of the Weichang District, was characterized by a mixed temperate forest of conifers (e.g. Pinus, Picea, Tsuga) and broad-leaved trees (e.g. Betula, Alnus), with some subtropical plants (e.g. Carya). The palaeoclimatic parameters of Guangfayong were obtained by applying the Coexistence Approach: the mean annual temperature from 7.8 to 14.9 °C, the difference of temperature between the coldest and warmest months from 14.2 to 23 °C, the mean temperature of the coldest month from − 3 to 5.9 °C, the mean temperature of the warmest month from 23.5 to 25.4 °C, the mean annual precipitation from 658.7 to 1389.4 mm, the minimum monthly precipitation from 7.6 to 16.4 mm, and the maximum monthly precipitation from 161.4 to 205.9 mm. It suggests a warm temperate to subtropical climate in Weichang District, similar to that of present-day Zhaojue City, Sichuan Province in the Yangtze River Valley. When the palaeoclimatic parameters were compared with those of Middle Miocene Shanwang Basin, it would seem that the temperature and precipitation were a little higher in the Middle Miocene of eastern China. However, if the latitudinal temperature gradient at that time is considered, the median temperature values of GFY of Early Miocene and Shanwang of Mid-Miocene were similar.  相似文献   

8.
The Earliest Normal Flower from Liaoning Province, China   总被引:1,自引:0,他引:1  
The early evolution of angiosperms has been a focus of intensive research for more than a century. The Yixian Formation in western Liaoning yields one of the earliest angiosperm macrofloras. Despite multitudes of angiosperm fossils uncovered, including Archaefructus and Sinocarpus , no bona fide normal flower has been dated to 125 Ma (mega-annum) or older. Here we report Callianthus dilae gen. et sp. nov. from the Yixian Formation (Early Cretaceous) in western Liaoning, China as the earliest normal flower known to date. The flower demonstrates a typical floral organization, including tepals, androecium, and gynoecium. The tepals are spatulate with parallel veins. The stamens have a slender filament, a globular anther, bristles at the anther apex, and in situ round-triangular pollen grains. The gynoecium is composed of two stylate carpels enclosed in a fleshy envelope, and develops into a "hip" when mature. Since the well-accepted history of angiosperms is not much longer than 125 Ma, Callianthus together with Chaoyangia, Archaefructus and Sinocarpus from the Yixian Formation demonstrate a surprisingly high diversity of angiosperms, implying a history of angiosperms much longer than currently accepted.  相似文献   

9.
The early evolution of angiosperms has been a focus of intensive research for more than a century. The Yixian Formation in western Liaoning yields one of the earliest angiosperm macrofioras. Despite multitudes of angiosperm fossils uncovered, including Archaefructus and Sinocarpus, no bona fide normal flower has been dated to 125 Ma (mega-annum) or older. Here we report Callianthus dilae gen. et sp. nov. from the Yixian Formation (Early Cretaceous) in western Liaoning, China as the earliest normal flower known to date. The flower demonstrates a typical floral organization, including tepals, androecium, and gynoecium. The tepals are spatulate with parallel veins. The stamens have a slender filament, a globular anther, bristles at the anther apex, and in situ round-triangular pollen grains. The gynoecium is composed of two stylate carpels enclosed in a fleshy envelope, and develops into a "hip" when mature. Since the well-accepted history of angiosperms is not much longer than 125 Ma, Callianthus together with Chaoyangia, Archaefructus and Sinocarpus from the Yixian Formation demonstrate a surprisingly high diversity of angiosperms, implying a history of angiosperms much longer than currently accepted.  相似文献   

10.
辽东山区典型人工针叶林土壤细菌群落多样性特征   总被引:7,自引:2,他引:7  
为揭示不同人工林树种对土壤养分和土壤微生物群落的影响,采用Illumina MiSeq高通量测序和OTU分析法比较辽东山区白石砬子自然保护区落叶松人工林(LGe)和红松人工林(PKe),以及辽宁省森林经营研究所实验林场落叶松人工林(LGd)和红松人工林(PKd)土壤细菌群落结构的差异,同时测定土壤理化性质,探讨土壤细菌群落结构、树种和土壤环境因子的相关性。研究结果表明:(1) LGe和PKe土壤全碳、全氮和碱解氮的含量无显著差异,LGd显著高于PKd。(2)从群落组成来看,该地区落叶松和红松人工林中土壤主要由34个门类群的菌群组成,优势菌群包括变形菌门、放线菌门、酸杆菌门、绿弯菌门、疣微菌门和芽单胞菌门。(3)从群落结构来看,LGe和PKe土壤细菌的多样性和丰富度指数无显著差异,PKd的多样性指数显著极高于LGd,丰富度指数无显著差异,且Metastats分析结果表明,较LGd和PKd相比,LGe和PKe在门水平和属水平上显著差异的个数较少,表现为趋同性。(4)优势细菌类群相对丰度和土壤理化性质的RDA和相关性分析表明,土壤p H、全氮、碱解氮的含量以及C/N是本区针叶林细菌群落结构的主要影响因子。综合分析表明,在保护区选择单一树种落叶松或红松造林对改善土壤养分及优化微土壤细菌群落结构无显著差异,而在实验林场选择落叶松更有利于提高土壤肥力。  相似文献   

11.
Chancelloriid sclerites from the lowermost Cambrian Xinji Formation (Series 2, Stage 3), southern margin of the North China platform, are systematically described. Thousands of isolated sclerites from three sections are assigned to three genera and four species, including Chancelloria cf. eros, Allonnia tripodophora, Archiasterella pentactina, and Ar. tetraspina. To accurately document the taxonomic significance of the sclerite structure, modified formulas (m+nC, m+nA, and m+0) are put forward to represent the full series and variation of sclerite forms. Based on the sclerite construction, statistical analysis on the proportions of different sclerite forms in the rock samples and the composition of sclerites in previously described chancelloriid scleritomes, a new scheme for identification and classification of isolated sclerites reconciled within the framework of the complete scleritome, is proposed.  相似文献   

12.
Phosphorites of the late Neoproterozoic Doushantuo Formation exposed in the vicinity of Weng'an, Guizhou Province, and Chadian, Shaanxi Province, South China, contain exceptionally well-preserved algal thalli, acritarchs, and globular microfossils interpreted as animal embryos. Combined optical microscopic and SEM observations provide insights into the taphonomy of phosphatized fossils. Algal cells and tissues are variably resistant to decay, and within preserved populations permineralization began at varying stages of degradation. In consequence, there is a spectrum of quality in cellular preservation. Algal cell walls, acritarch vesicles, and embryo envelopes are commonly encrusted by an isopachous rim of apatite, with cell interiors filled by collophane and later diagenetic dolomite. In contrast, blastomere surfaces of animal embryos are encrusted primarily by minute phosphatic spherules and filaments, possibly reflecting an immediately postmortem infestation of bacteria that provided nucleation sites for phosphate crystal growth. Thus, the same processes that gave rise to Phanerozoic phosphatized Lagerstätten - phosphatic encrustation, and impregnation, probably mediated by microbial activity - effected soft-tissue preservation in the Doushantuo Lagerstätte. It remains unclear how phosphatic ions and organic macro-molecules interact at the molecular level and to what extent specific microbial metabolisms or microenvironmental conditions control the phosphatization of soft tissues. New observations of phosphatized Doushantuo fossils include: a second locality (Chadian) for Wengania globosa , interpreted as an algal thallus and previously known only from Weng'an; microtunnels in Weng'an phosphorites interpreted as pyrite trails; and new taxa described from Weng'an: Meghystrichosphaeridium reticulatum (acritarch), Sarcinophycus radiatus (algal thallus), and one unnamed problematic form.  相似文献   

13.
寒武系腕足动物属种多样性高、个体数量丰富、形态差异明显、地理分布广泛,具有辅助寒武系三叶虫生物地层划分和对比的潜力.华北板块寒武系苗岭统沉积和化石记录发育良好,是中国苗岭统的经典研究区之一.前人己针对华北寒武系苗岭统乌溜阶腕足动物的系统古生物学开展了一系列基础工作,但这些相关研究主要集中于辽宁地区,目前对华北其他地区苗...  相似文献   

14.
《Palaeoworld》2020,29(3):512-533
Abundant and diverse small shelly fossils have been reported from Cambrian Series 2 in North China, but the co-occurring brachiopods are still poorly known. Herein, we describe seven genera, five species and two undetermined species of organophosphatic brachiopods including one new genus and new species from the lower Cambrian Xinji Formation at Shuiyu section, located on the southern margin of North China Platform. The brachiopod assemblage comprises one mickwitziid (stem group brachiopoda), Paramickwitzia boreussinaensis n. gen. n. sp., a paterinide, Askepasma toddense Laurie, 1986, an acrotretoid, Eohadrotreta cf. zhenbaensis Li and Holmer, 2004, a botsfordiid, Schizopholis yorkensis (Holmer and Ushatinskaya in Gravestock et al., 2001) and three linguloids, Spinobolus sp., Eodicellomus cf. elkaniiformis Holmer and Ushatinskaya in Gravestock et al., 2001 and Eoobolus sp. This brachiopod assemblage suggests a late Age 3 to early Age 4 for the Xinji Formation and reveals a remarkably strong connection with coeval faunas from East Gondwana, particularly the Hawker Group in South Australia. The high degree of similarity (even at species level) further supports a close palaeogeographic position between the North China Platform and Australian East Gondwana during the early Cambrian as indicated by small shelly fossil data.  相似文献   

15.
《Palaeoworld》2020,29(1):66-74
The Hungshihyen Formation represents the Lower to Middle Ordovician near-shore siliciclastic deposits on the western margin of the Yangtze Platform, South China. However, its age is still debated, largely because of insufficient studies. Here we documented the Bursachitina maotaiensisB. qianbeiensis chitinozoan assemblage from the lower part of the Hungshihyen Formation at Songliang, Qiaojia County, eastern Yunnan Province. This assemblage is remarkably similar to an assemblage that roughly correlates to the middle part of the Corymobograptus deflexus graptolite Biozone in northern Guizhou Province, indicating that the Hungshihyen Formation at Songliang is probably of late Floian age and may extend into the early Dapingian. Additionally, a revision on the chitinozoans previously documented from the strata assigned to the same formation in the Wuding area was made according to the latest classification. The revision allows the recognition of the Euconochitina symmetricaEremochitina brevis assemblage, and therefore suggests a late Tremadocian age for this interval based on regional and global chitinozoan biostratigraphic correlations. Considering also its lithologic succession, we argue that the chitinozoan-bearing strata in the Wuding area previously assigned to the Hungshihyen Formation correspond most likely to the uppermost part of the underlying Tangchi Formation or the lowermost part of the Hungshihyen Formation. The base of the Hungshihyen Formation appears therefore to be diachronous in eastern Yunnan Province.  相似文献   

16.
长城群高于庄组主要分布于我国华北地区,地质年龄约在14-16亿年。主要描述了华北太行山北段灵邱县境内高于组白云岩中的层状和扁豆状透镜体燧石及穹隆式叠层石的黑色燧石中的颤藻、念珠藻和色球藻植物的8个新种和3个未定种,其中还有两个新修订属。这些新的促群再加上前人在高于庄组地层中已报道的汇成了近100个种生物组合,进一步证明高于庄组地地球上中元代微化石类群最丰富的产地之一。以下是该 新发现和新修订的分类类群:颤藻科(Oscillatoriaceae): Eophormkidium orculiformis sp. nov., E. sp., Siphonophycus caudataceous sp. nov., Palaeolyngbya complanata sp. nov., P. capitata sp. nvo., P. sp., Oscilaltoriopsis sp.;念珠藻科(Nosto-caceae):Veteronostiocale vaginata sp.nov.;色球藻科(Chroococcaceae):Maculosphaera giganta sp.nov.,Gloeotheceopsis grandis sp.nov.;分类位置未定的类群:Myxococcoides limpida sp.nov.。  相似文献   

17.
A new diverse assemblage of microorganisms has been discovered in black bedded, nodular and lenticular cherts and dark chert of domical stromatolites in dolostone of the Gaoyuzhuang Formation in Lingqiu County, northern Taihang Mountains. The geologic relationships, biostratigraphic correlations, and available radiometric age determinations place the age of the Gaoyuzhuang Formation at approximately 1 400-1 600 million years in age. Eight new species, three unnamed species, and two emended genera of oscillatoriacean, nostocacean, and chroococcacean cyanobacteria are described. These data coupled with reports of others indicate that the diversity of taxa in the Gaoyuzhuang Formation reaches 100 species. The Gaoyuzhuang Formation contains one of the richest Mesoproterozoic communities of microfossils. The following new and emended taxa are described: Oscillatoriaceae: Eophormidium orculiformis sp. nov., E . sp., Siphonophycus caudataceous sp. nov., Palaeolyngbya complanata sp. nov., P. capitata sp. nov., P . sp. and Oscillatoriopsis sp..Nostocaceae: Veteronostocale vaginata sp. nov.. Chroococcaceae: Maculosphaera giganta sp. nov. and Gloeotheceopsis grandis sp. nov. Incertae sedis: Myxococcoides limpida sp. nov.  相似文献   

18.
The genus Calocedrus Kurz is characterized by flattened branches covered with decussate and dimorphic leaves. In this study, we describe fossil foliage of Calocedrus discovered in the Shangcun Formation (early Oligocene) of the Maoming Basin, South China. The fossils have wedge‐shaped branchlet segments and scale‐like strongly dimorphic leaves, similar to the fossil species Calocedrus lantenoisi (Laurent) Tao. There have been no detailed studies of the morphological features and cuticle structures of C. lantenoisi. Therefore, a newly emended diagnosis of the species C. lantenoisi is given based on a detailed study of leaf morphology and cuticular characters exhibited by the Maoming fossils. This is one of the earliest fossil records of Calocedrus in the world, providing additional evidence for the early biogeographic history of this genus and supporting the inference that eastern Asian Calocedrus is primitive among all the living species. The extant species of Calocedrus are mainly distributed in mountainous regions. On the basis of the “nearest living relative” analysis, we propose that the Maoming Basin was adjacent to a mountainous region during the early Oligocene.  相似文献   

19.
《Palaeoworld》2014,23(2):112-124
The Tangwangzhai section, western Shandong Province, North China, the type section for the Cambrian Kushan and Chaomitian formations, yielded a diverse and relatively well-preserved conodont fauna, in which we recognize the Westergaardodina orygma, Westergaardodina matsushitai, Muellerodus? erectus, and Westergaardodina aff. fossaProoneotodus rotundatus zones of the North China conodont zonation. The Tangwangzhai conodont succession can be correlated not only with the polymerid trilobites occurring in the section but also with the conodont zones established for South China. The first occurrence of Furnishina longibasis and Furnishina quadrata in the upper part of the Westergaardodina matsushitai Zone allows the recognition of the base of the Paibian Stage and Furongian Series in the upper part of the Kushan Formation. The base of the Jiangshanian Stage, in the uppermost Muellerodus? erectus Zone, can be recognized by the presence of Westergaardodina cf. calix close to the base of the Chaomitian Formation. Chemostratigraphic analyses of the Tangwangzhai section show the onset of a positive carbon isotope excursion, referred to the SPICE event, in the upper part of the Kushan Formation at a level corresponding to the first occurrence of F. longibasis and F. quadrata. The base of the Jiangshanian Stage in the section is close to the demise of the SPICE positive excursion.  相似文献   

20.
张武  郑少林 《Acta Botanica Sinica》1999,41(12):1312-1316
报道了辽宁早白垩世化石木的一个新属—原始金松型木 (Protosciadopityoxylongen .nov .)。该属化石以辽宁原始金松型木 (Protosciadopityoxylonliaoningensegen .etsp .nov .)为代表。文中对新属新种进行了描述 ;讨论了新属与现存金松属 (Sciadopitys)及化石金松型木属 (Sciadopityoxylon)的关系 ;并与其相似的原始叶枝杉型木属 (Protophyl locladoxylon)、原始圆孔木属 (Protocircoporoxylon)及异木属 (Xenoxylon)作了比较。  相似文献   

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