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1.
河南叶县下寒武统辛集组单板类和腹足类化石的研究   总被引:5,自引:3,他引:5  
本文描述和讨论了河南叶县杨寺庄下寒武统辛集组单板类13种,腹足类2种,未定类1种。其中包括2新属6新种:Repenoconus xinjiensis gen.nov.,Scenella pycna sp.nov.,Securiconus vulgaris sp.nov.,Obtusocnus grossicostus sp.nov.,Igorellina proboscis sp.nov.,Gal  相似文献   

2.
冯伟民  孙卫国  钱逸 《微体古生物学报》2000,17(4):362-377,T005,T007
本文描述了云南东部早寒武世早期梅树村阶软体动物单板类化石,计有5新属7新种和1个未定种,它们是Striatoconus yuluensis gen.et sp.nov.,Striatoconus sp.,Aegitellus concenttricus gen.et sp.nov.,Tubatoconus yuluensis gen.et sp.nov.,Papilloconus explanat  相似文献   

3.
早寒武世马哈螺类的骨骼化特征、分类和演化意义   总被引:3,自引:0,他引:3  
马哈螺类(maikhanellids)是已知最古老的单板类,以往缺乏系统研究,并在分类上争议较大,文中以滇东早寒武世梅树村阶微小骨骼化石的丰富材料为依据,详细阐述该类群的形态特征和超微结构,探讨其亲缘关系和演化趋势,研究表明,马哈螺类由6个属组成,包括Maikhanella,Ramenta,Ramentoides gen.nov.,Mediata gen.nov.,Yunnanopleure和Purella。各属之间壳形变化较大,但裸露的壳顶和普遍发育的鳞片状或条状突起表明它们在明显的亲缘关系,并显示两个演化方向,即Maikhanella Ramentoides gen.nov.Ramenta和Maikhanella Mediata gen.nov.Yunanopleura-Purella。马哈螺类分布于梅树村期早,中期,Maikhanella是最原始的马哈螺,最先出现在梅树村阶小歪头山段,也是中谊村段下磷矿层唯一的马哈螺,而在该段上磷矿层马哈螺类发生了明显的属种分异,在大少段所有的马哈螺类突然消失,马哈螺类的壳体曾被描述为:骨针状的外骨骼”,“骨片状外骼”和“包裹在中间基质中的骨针”,但当前研究表明,以Maikhanella pristinis和Ramenta cambrina为代表的马哈螺类的内壳层具有早期单板类中较常见的水平交错纤状结构,指示了马哈螺类具有致密成层的壳壁,文中新建2亚科,2属和5种,即Maikhanellinae subfamily nov.,Purellinae subfamily nov.,Maikhanella Perelegans sp.nov.,Ramenta superata sp.nov.,Ramentoides latispinus gen.et sp.nov.,Mediata kunyangensis gen.et sp.nov.,Yunnanopleura longidens sp.nov。  相似文献   

4.
Abstract: Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty‐four specimens have been collected from the Middle Ordovician of the Builth‐Llandrindod Inlier of Mid Wales and include well‐preserved material assigned to seven new genera, with four additional species in open nomenclature. An additional specimen from the Arenig Pontyfenni Formation of South Wales is also described in open nomenclature. The total demonstrates much greater palaeoscolecid diversity than hitherto suspected for this time. The specimens are preserved as cuticle fragments in shales and siltstones, often of submillimetre size but in many cases with excellent preservation. The level of detail preserved in some is equal to that found in Cambrian phosphatized faunas. The new approach to collecting, and the recognition that this material can yield taxonomically useful information, opens new avenues for palaeoscolecidan research in siliciclastic environments. The new taxa are the following: Radnorscolex bwlchi gen. et sp. nov., Aggerscolex murchisoni gen. et sp. nov., Bullascolex inserere gen. et sp. nov., Wernia eximia gen. et sp. nov., Ulexiscolex ormrodi gen. et sp. nov., Pluoscolex linearis gen. et sp. nov. and Loriciscolex cuspidus gen. et sp. nov. The high diversity, and the taxonomic separation from known groups described primarily from Cambrian carbonates, implies that palaeoscolecidans either diversified significantly during the Ordovician or were taxonomically segregated between carbonate and siliciclastic settings. Palaeobiological findings also include confirmation that some palaeoscolecid basal cuticles were solid and others reticulate, plates (and platelets) could form by lateral accretion, plates were in part primarily phosphatic and in part organic and that in at least some groups, platelet secretion occurred external to plate secretion.  相似文献   

5.
New Archaeocyatha genera and species, Turgorocyathus elegans gen. et sp. nov., Angustocyathus porus gen. et sp. nov., Flossocyathus squamosus gen. et sp. nov., Rotundocyathus oimuranicus sp. nov., and Carinacyathus inopinatus sp. nov., from the type sections of the Atdabanian Stage of the Lower Cambrian of the Siberian Platform are described.  相似文献   

6.
龙凤山藻在澄江早寒武世生物群中的发现   总被引:4,自引:0,他引:4  
徐兆良 《Acta Botanica Sinica》2002,44(10):1250-1254
主要报道了产自云南昆明海口耳材村早寒武世筇竹寺组玉案山段澄江生物群中可能为漂浮生长的宏观藻类化石-心型龙凤山藻(新种)(Longfengshania cordata sp.nov.)和中华豆芽藻(新属、新种)(lantulaformis sinensis gen.et sp.nov)。这些化石的发现进一步显示了澄江生物群种物多样性,为揭示该生物群爆发性演化提供了新的证据。通过对龙凤山藻属亲缘关系的深入比较研究,进一步证明该类化石应归属宏观藻类以及它们遗传上的稳定性、演化上的保守性和环境上的适应性。  相似文献   

7.
主要报道了产自云南昆明海口耳材村早寒武世筇竹寺组玉案山段澄江生物群中可能为自由漂浮生长的宏观藻类化石--心型龙凤山藻(新种)(Longfengshania cordata sp. nov.)和中华豆芽藻(新属、新种)(Plantulaformis sinensis gen. et sp. nov.).这些化石的发现进一步显示了澄江生物群物种多样性,为揭示该生物群爆发性演化提供了新的证据.通过对龙凤山藻属亲缘关系的深入比较研究,进一步证明该类化石应归属宏观藻类以及它们遗传上的稳定性、演化上的保守性和环境上的适应性.  相似文献   

8.
Abstract:  A diverse fauna of three-dimensionally preserved sponges is described from nearshore volcanogenic sandstones near Llandrindod, Mid-Wales. The fauna was preserved through early marginal silicification, in rare examples with silicification of soft tissue, and includes aspicular and spicular demosponges, hexactinellids, and a heteractinid. The fauna is largely endemic, with the following new species, genera and families erected: Onerosiconcha gregalia gen. et sp. nov., Ordinisabulo quadragintaforma gen. et sp. nov., Miritubus erinaceus gen. et sp. nov., Vadosifistula milvus gen. et sp. nov., Polycornua trescelestus gen. et sp. nov. (Pseudolanciculidae fam. nov.), P. entropus sp. nov., Palaeocallyoides improbabilis gen. et sp. nov., Reticulicymbalum tres gen. et sp. nov., Triactinella rigbyi gen. et sp. nov. (Triactinellidae, fam. nov.), Spissiparies minuta gen. nov., Brevicirrus arenaceus gen. et sp. nov., Pyritonema scopula sp. nov. (Pyritonemidae, fam. nov.) and Microastraeum tenuis gen. et sp. nov. In addition, Pseudolancicula Webby and Trotter is recorded outside Australia for the first time, although only as isolated spicules. The environment represented by this fauna has not previously yielded articulated sponges, and thus the apparent endemism may be misleading.  相似文献   

9.
Exceptionally preserved ‘Burgess Shale‐type’ fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non‐biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerstätten. Here we report a diverse assemblage of small carbonaceous fossils (SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale‐type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as ‘protoconodonts’, denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high‐latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda gen. et sp. nov. (a priapulid), Baltichaeta jormunganda gen. et sp. nov. (an annelid) and Baltinema rana gen. et sp. nov. (a filamentous problematicum).  相似文献   

10.
Although priapulid worms form a relatively small phylum in present-day marine environments, they were important animals in Cambrian endobenthic communities. Two Early Cambrian priapulids, namely Xiaoheiqingella peculiaris and Yunnanpriapulus halteroformis nov. gen., nov. sp. from the Maotianshan Shale Lagerstätte of SW China are revised and described. Several key-features of the body plan of Recent Priapulidae are recognized in these two forms: 1) the four-fold body division (introvert, neck, trunk, and caudal appendage); 2) the well-developed introvert armed with ca. 25 longitudinal rows of scalids; 3) the caudal appendage; 4) the pharyngeal teeth arranged in a pentagonal disposition (Xiaoheiqingella); 5) the ventral nerve cord present in Yunnanpriapulus. This morphology indicates close evolutionary relationships with modern priapulids. Xiaoheiqingella and Yunnanpriapulus nov. gen. are tentatively placed within the recent family Priapulidae. The Priapulidae lineage may therefore have a remote origin (Early Cambrian) much older than was previously assumed (Priapulites; Late Carboniferous). The functional morphology of Xiaoheiqingella and Yunnanpriapulus nov. gen. suggests that these two worms were chiefly carnivorous with possible occasional mud-eating habits.  相似文献   

11.
辽西义县组细蜂总科(昆虫纲,膜翅目)昆虫化石   总被引:4,自引:0,他引:4  
描述了产自辽宁北票上园地区黄半吉沟上株罗统义县组下部细蜂总科(Proctotrupoidea)昆虫化石10属12种,其中8属12新种,这些化石分属于3科,其中Gurvanotrupes stolidus sp.nov.,Gurvanotrupes exiguus sp.nov.,Liaoserphus perarus gen.et sp.no.,alloserphus saxosus gen.et sp.nov.,Scalprogaster fossilis gen.et sp.nov.,steleoserphus beipiaoensis gen.et sp.nov.,Saucrotrupes decorosus gen.et sp.nov和Ocnoserbphous sculptus gen.et sp.nov.归入细蜂科(Serphidae=Proctotrupidae);Protocyrtus validus sp.nov.和Spherogaster cornoata gen.et sp,nov。归入柄腹细蜂科(heloridae);Liaoropronia leonina gen.et sp.nov和Liaoropronia regia gen.et sp.nov.归入窄腹细蜂科(Roproniidae),对我们中生代细蜂总科化石的研究状况作了回顾。  相似文献   

12.
本文描述古蝉科化石2新属、6新种,即Liaocossushuegen.etsp.nov.,L.beipiaoensisgen.etsp.nov,L.exiguusgen.etsp.nov,L.fengningensisgen.etsp.nov,L.Pingquanensisgen.etsp.nov.,Miracossusingentiusgen.etsp.nov.。这批化石保存有完整的虫体标本,使作者能够进一步研究古蝉类化石的虫体特征。化石采于冀北和辽西晚侏罗世义县组地层中,保存在中国地质博物馆。  相似文献   

13.
The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity ( Sahnioxylon ; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov.  相似文献   

14.
Invasion of the open ocean by tetrapods represents a major evolutionary transition that occurred independently in cetaceans, mosasauroids, chelonioids (sea turtles), ichthyosaurs and plesiosaurs. Plesiosaurian reptiles invaded pelagic ocean environments immediately following the Late Triassic extinctions. This diversification is recorded by three intensively-sampled European fossil faunas, spanning 20 million years (Ma). These provide an unparalleled opportunity to document changes in key macroevolutionary parameters associated with secondary adaptation to pelagic life in tetrapods. A comprehensive assessment focuses on the oldest fauna, from the Blue Lias Formation of Street, and nearby localities, in Somerset, UK (Earliest Jurassic: 200 Ma), identifying three new species representing two small-bodied rhomaleosaurids (Stratesaurus taylori gen et sp. nov.; Avalonnectes arturi gen. et sp. nov) and the most basal plesiosauroid, Eoplesiosaurus antiquior gen. et sp. nov. The initial radiation of plesiosaurs was characterised by high, but short-lived, diversity of an archaic clade, Rhomaleosauridae. Representatives of this initial radiation were replaced by derived, neoplesiosaurian plesiosaurs at small-medium body sizes during a more gradual accumulation of morphological disparity. This gradualistic modality suggests that adaptive radiations within tetrapod subclades are not always characterised by the initially high levels of disparity observed in the Paleozoic origins of major metazoan body plans, or in the origin of tetrapods. High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself. Increase in both maximum and minimum body length early in plesiosaurian history suggests a driven evolutionary trend. However, Maximum-likelihood models suggest only passive expansion into higher body size categories.  相似文献   

15.
湖北省鹤峰白果坪剖面下寒武统水井沱组底部黑色燧石的岩石薄片中,发现有丰富的保存完好的微化石,包括球形藻、刺球藻、丝状藻类及一些分类不明的微化石。经初步研究计有6属9种类型。其中包括1新属Spiciformagen.nov.和2个新种Spiciformaagglomeratagen,etsp.nov.和?Retinaritesspiralissp.nov.。这一发现进一步丰富了早寒武世早期硅质岩相地层的微体化石资料,为相关地层的对比提供了可资参考的古生物学依据。  相似文献   

16.
中国东北晚侏罗世虻类化石(昆虫纲:双翅目)   总被引:5,自引:0,他引:5  
本文论述了辽宁西部上侏罗统虻类6个科的化石,包括1新科,10个新属和15个新种。其中Palaepangonius eupterus gen.et sp.nov.,Elpangonius pletus gen,et sp.nov.和Allomyia ruderalis gen.et sp.nov.均属于虻科(Tabanidae);Orsobrachyceron chinensis gen.et sp  相似文献   

17.
The problematic lizard family Changjiangosauridae, representatives of which inhabited Asia in the Early Paleogene, is discussed. Six new species of this group, including Acrodontopsis robustus gen. et sp. nov., Agamimus gracilis gen. et sp. nov., Graminisaurus interruptus gen. et sp. nov., Khaichinsaurus reshetovi gen. et sp. nov., Lavatisaurus elegans gen. et sp. nov., and Lentisaurus giganteus gen. et sp. nov., from the Middle Eocene of the Khaichin Uul 2 locality (southern Gobi, Mongolia) are described. It is shown that Changjiangosauridae are probably related to the Late Cretaceous Isodontosauridae and recent Uromastycidae; independent development of a number of dental features in different lineages of Acrodonta (Iguania) is corroborated.  相似文献   

18.
The paper deals with the new phaeophycean fossils in the Early Cambrian from Chengjiang Biota at Ercai Village of Haikou, Kunming, Yunnan, Southwest China. Three new taxa, Punctariopsis latifolia gen. et sp. nov., P.simplex gen. et sp. nov. and Vendotaenia cf. antiqua Gnilovskaya are described here in detail. These new findings show that the Chengjiang Biota is high in species diversity of fossil algae and might offer new evidence for a better understanding of the Cambrian explosive biological evolution. The fossil genus described here is found to have a close relationship with the living Punctaria based on similar morphology. The results suggest that the Chengjiang Biota in Haikou area of Kunming was living in an intertidal and subtidal seawater environment.  相似文献   

19.
Abstract: Red calcareous Middle Cambrian palaeosols from the upper Moodlatana Formation in the eastern Flinders Ranges of South Australia formed in well‐drained subhumid floodplains and include a variety of problematic fossils. The fossils are preserved like trace fossil endichnia but do not appear to be traces of burrows or other animal movement. They are here regarded as remains of sessile organisms, comparable with fungi or plants living in place, and are formally named as palaeobotanical form genera under provisions of the International Code of Botanical Nomenclature. Most common are slender (0.5–2 mm) branching filaments flanked by green‐grey reduction haloes within the red matrix of palaeosol surface horizons (Prasinema gracile gen. et sp. nov.). Other axial structures (Prasinema nodosum and P. adunatum gen. et spp. nov.) are larger and show distinctive surface irregularities (short protuberances and irregular striations, respectively). The size and form of these filaments are most like rhizines of soil‐crust lichens. Other evidence of life on land includes quilted spheroids (Erytholus globosus gen. et sp. nov.) and thallose impressions (Farghera sp. indet.), which may have been slime moulds and lichens, respectively. These distinctive fossils in Cambrian palaeosols represent communities comparable with modern biological soil crusts.  相似文献   

20.
云南海口早寒武世褐藻化石新知   总被引:4,自引:2,他引:2  
徐兆良 《Acta Botanica Sinica》2001,43(10):1072-1076
主要报道了产自云南海口耳材村早寒武世筇竹寺组玉案山段澄江生物群中的褐藻化石-拟点叶藻(Punctariopsis latifolia gen.et sp.nov.)简单拟点叶藻(Punctariopsis simplex gen.etsp.nov.)和古德带藻(Vendotaenia cf.antiqua Gnilovskaya)3种。这些化石丰富了澄江生物群物种的多样性,为研究该群生物爆发性演化提供了新的证据。同时通过对现生褐藻和褐藻化石形态学的比较研究,表明化石属和现代属在系统演化上可能有较密切的亲缘关系,并进一步证明了澄江生物群在云南海口地区发生于一个潮间带和亚潮带的海水环境。  相似文献   

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