昆明海口早寒武世澄江生物群中叶状红藻化石

主要报道了采自云南省昆明市海口马房村鞍山早寒武世筇竹寺组玉案山段澄江生物群中的叶状红藻-似红叶藻(新属、新种)(Paradelesseria sanguinea Xu,gen.et sp.Nov.).通过比较形态学研究,探讨了该宏观化石藻类的分类归属与亲缘关系,进一步丰富了澄江生物群生物物种多样性的认识,并为研究早寒武世生物演化及其古环境提供了新的化石证据.同时,通过对现生红藻的比较研究,进一步证明了澄江生物群在云南海口地区发生于一个水深在30 m以上的亚潮带和下潮间带的海水环境.     

云南海口早寒武世褐藻化石新知

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。     

龙凤山藻在澄江早寒武世生物群中的发现

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。     

龙凤山藻在澄江早寒武世生物群中的发现

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.     

云南早寒武世澄江化石库中两种埋藏相的化石定量分析

通过昆明海口马房村同一个采坑的化石连续采集和统计,对澄江化石库中两种埋藏相(以事件层泥岩和背景层泥岩所代表)内化石保存和组合特征进行定量研究,结果表明:(1)事件层内化石量并不随单一事件层厚度变化而变化。物种在剖面上不同层位的事件层内分布不均匀,表现为单层富集现象;而背景层内的化石含量与背景层的沉积厚度有关,背景层的沉积厚度越厚,化石数量就越多。(2)事件层与背景层内化石组合和结构存在很大差异。事件层内化石组合与背景层内化石组合相比具有更多的物种组成和更复杂的古群落结构;而背景层内化石组合面貌单调,在剖面上保持稳定。(3)事件层内化石生物体腐烂发生在埋藏之后,绝大多数化石生物是被活埋后保存下来的;而背景层内化石主要表现为外壳和弱矿化有机质生物表皮在海床表面长时间停滞而堆积形成,明显受到时间均衡作用(time-average)的影响。(4)事件层内化石在埋藏前无搬运作用,或发生近原栖息地的快速搬运,埋藏后无生物扰动。背景层内大量壳体相连的双瓣壳节肢动物化石和完整海绵体化石的存在则表明,背景层代表一个低氧、低能并具有有限生物扰动的沉积环境。     

云南早寒武世澄江动物群稀有节肢动物新材料

描述3块新的标本,分别是节肢动物Pisinnocaris sp．,Tanglangia longicaudata Luo et Hu,1999和Pygmaclypeatus daziensis Zhang,Han et Shu,2000。新的标本进一步增进我们对其形态结构特征的了解。通过与相关属种的比较,简要讨论其系统位置问题。     

云南澄江早寒武世黑林铺组软体动物太阳女神螺

云南澄江及梅树村早寒武世黑林铺组（玉案山段及石岩头段）的帽形化石,被命名为云南太阳女神螺（新种）,这是澄江生物群内软体动物化石的初次发现。根据梅树村及澄江的地层层位,该种由梅树村阶上部可延至筇竹寺阶,玉案山段软体动物稀少的原因与环境的波动,如潮汐影响近海沉积环境有关。     

浙西早寒武世梅树村期棒状化石

该文记述了浙江省西部江山县新塘坞地区灯影组(梅树村期)中新发现的矿化骨骼化石——浙江棒(新属)Zhejiangorhabdion gen.nov.。该化石的形态与以往化石类群均不相同,为个体微小的棒状,表面具较复杂的纹饰,不同个体间的纹饰都有一定变化,推测是动物体内不同部位的骨棒所具有的特征,代表了一个新的化石类群。新属的发现丰富了梅树村期动物群的内容,对了解具骨骼动物群体在这一时期的演化具有一定的意义。     

拟浒苔在澄江生物群中的发现及其生态学意义

报道了早寒武世澄江生物群中的一种新的化石藻类－肠拟浒苔（Enteromophites intestinalis sp.nov）,丰富了对该时期生物多样性的认识,通过现生浒苔属和石拟苔属藻类形态学的研究表明,这两个属在系统演化上可能有密切的亲缘关系,并阐述了澄江生物群可能发生了一个海水环境。     

云南早寒武世化石库中的鳃足类和遗迹化石的共生标本

笔者在参加中国古生物学会 2 2届学术年会期间 ,有幸听了贵州工业大学的王约老师作的关于凯里生物群中的一些水母状动物化石和遗迹化石共生保存研究的学术报告 ,在王老师的报告中 ,展示了很多奇特的水母状化石的标本 ,在这些水母状化石的标本上都可以看到有很多虫迹化石分布。有的穿插整个水母状动物而过 ,有的从边缘穿插 ,有的在动物的中部向下潜穴。目前认为这些遗迹是由于造迹生物去吃死去的水母状动物的腐烂尸体而形成的 ,这个理论得到了多数人的认可。回云南之后 ,我观察了我们云南出产的很多甲壳类生物的表面 ,同样发现了很多遗迹化石…     

Hyolith-type microstructure in a mollusc-like fossil from the Early Cambrian of Yunnan, China

A phosphatized bilaterally symmetrical, spirally coiled conch from the Lower Cambrian phosphates of the Meishucunian Stage of eastern Yunnan, China, is composed of two well-preserved layers. The outer one is built of longitudinal mineralized fibres not strictly parallel to each other, but may anastomose or branch. The fibres form comarginal ribs with transversal grooves between them, corresponding to growth stages. In the ribs, the fibres are arranged closely and are steeply inclined towards the apex, while in the grooves the fibres are subparallel to the conch surface and more loosely packed. Small elliptic and triangular holes are situated within and between the fibres of the outer layer. The inner layer consists of transversal fibres running around the conch. They are almost parallel to each other but partly separated by narrow discontinuous slits. Despite overall morphological similarity of the conch to shells of some early Cambrian molluscs, the observed orthogonal configuration of longitudinally oriented fibrous structures of the outer layer and transversal fibres of the inner layer is found in orthothecid hyoliths, phosphatized microstuctures of which have been described from the Lower Cambrian of the Siberian Platform. The new material from the Yangtze Platform supports a conclusion of a distinctive type of microstructure available in hyoliths different from molluscan microstructures available from the Lower Cambrian.     

Cambrian anemones with preserved soft tissue from the Chengjiang biota, China

The group Cnidaria includes 'jellyfish', soft-bodied anemone and anemone-like forms and calcified corals. These diploblastic organisms have a fossil record extending back to the earliest metazoans of the Neoproterozoic; however certain cnidarians of the subclass Zoantharia, characterized by soft-bodied anemone-like forms, are absent or poorly represented in the fossil record. Despite the paucity of fossils, it is thought that calcification by soft anemone-like animals was responsible for producing the skeleton that allowed the preservation of the first corals. We report discovery of an abundant assemblage of in situ soft-bodied polyps with tissues. They are preserved in exquisite detail and come from the well-known Lower Cambrian Chengjiang biota of Yunnan, China. The soft-bodied polyps display a simple anatomy that is comparable to some extant anemones of the order Actinaria. The new fossils are assigned to Archisaccophyllia kunmingensis n. gen. et n. sp. Their simple and conservative form suggests that these fossils may represent some kind of ancestral rootstock. The preserved life assemblage provides a unique snapshot of Lower Cambrian anemone life and provides clues for relationships with extant actiniarians as well as calcified corals.     

Reconsideration of the supposed naraoiid larva from the Early Cambrian Chengjiang Lagerstätte, South China

The Chengjiang Lagerstätte in the Lower Cambrian of South China yields a small, larva‐like arthropod, which was considered to be a protaspis of naraoiids by many authors. The discovery of a large number of well‐preserved specimens from many new localities has allowed the original study to be revised. The relatively large size, stable morphology and unusual structure of the appendages indicate that these specimens represent adults of a new arthropod, Primicaris larvaformis. The larva‐like outline is considered to have arisen by the heterochronic process of progenesis. In addition, this animal displays primitive aspects of bodyplan and limb morphology that suggest a basal position within arachnomorphs, or perhaps even arthropods, and the similarities to the Vendian arthropod‐like animal Parvancorina probably provide an evolutionary link between Vendian forms and Cambrian arthropods.     

The lobopodian Paucipodia inermis from the Lower Cambrian Chengjiang fauna, Yunnan, China

New specimens of Paucipodia inermis Chen, Zhou & Ramsköld, 1995, are described from the Lower Cambrian Chengjiang Lagerstätte in Haikou, Kunming. Details not previously seen in the Chengjiang material appear to be caused by early diagenetic processes. Some features not previously observed in Palaeozoic lobopodians include details of the dermomuscular sac, body cavities, contents of the gut, possible paired ventral nerve ganglia, and a rasping or biting apparatus with teeth. The latter implies a fundamental difference from onychophorans and rules out an ancestral position for Palaeozoic lobopodians. The supposed tail is shown to be the head, and it is shown that this animal possessed nine pairs of lobopods rather than six, as originally stated. The family Paucipodiidae n. fam. is introduced.     

Revision of the Cambrian discoidal animals Stellostomites eumorphus and Pararotadiscus guizhouensis from South China

The discoidal fossils identified as Stellostomites eumorphus Sun & Hou, Rotadiscus grandis Sun & Hou and Rotadiscus guizhouensis Zhao & Zhu are abundant in the Cambrian Chengjiang and Kaili Lagerstätten of southwest China. Reinvestigation of all available specimens of S. eumorphus and R. guizhouensis indicates that S. eumorphus has radiating lobe structures different from those of Eldonia ludwigi Walcott and has one additional set of dorsal radiating canals, and has a distinct central cavity, two characters that are not present in E. ludwigi. R. guizhouensis differs from R. grandis in the morphology of the disc, internal radiating lobes and tentacles. This supports the validity of the genus StellostomitesSun & Hou, 1987, and substantiates the erection of a new genus, Pararotadiscus nov. gen., to receive Rotadiscus guizhouensis Zhao Zhu, 1994. Anatomical and taphonomical analyses indicate that S. eumorphus and P. guizhouensis were gregarious pelagic animals. The new anatomical information emphasize close phylogenetic relations with lophophorates (U-shaped intestine, circumoral tentacles and ectodermal, marginal accreted disc), though some features (e.g. dendritic tentacles, ventral pustules that may relate to reduced podia) do not exclude affinitics with echinoderms.