贵州剑河八郎寒武系甲劳组太阳女神螺类Oelandiella*

首次报道贵州剑河八郎地区寒武系甲劳组下部粉砂质、砂质页岩中的太阳女神螺类化石小厄兰岛螺属(Oelandiella Vostokova,1962)1相似种:Oelandiellacf.accordinonata(Runnegar and Jell,1976)emended Yang et al.,2012。剑河甲劳组Oelandiella可见较为显著横过背脊并在壳体两侧对称的同缘褶,推测其可能是在正常浅海环境中形成,因此,该化石的发现和研究将有助于了解甲劳组的沉积环境,为深入探讨其沉积环境提供新的证据。同时,确认寒武系第三统台江阶的甲劳组是Oelandiella在黔东地区的最高产出层位,为研究寒武纪太阳女神螺类软体动物的分类、演化等提供更多的化石材料。     

An Early Cambrian stem polychaete with pygidial cirri

The oldest annelid fossils are polychaetes from the Cambrian Period. They are representatives of the annelid stem group and thus vital in any discussion of how we polarize the evolution of the crown group. Here, we describe a fossil polychaete from the Early Cambrian Sirius Passet fauna, Pygocirrus butyricampum gen. et sp. nov., with structures identified as pygidial cirri, which are recorded for the first time from Cambrian annelids. The body is slender and has biramous parapodia with chaetae organized in laterally oriented bundles. The presence of pygidial cirri is one of the characters that hitherto has defined the annelid crown group, which diversified during the Cambrian-Ordovician transition. The newly described fossil shows that this character had already developed within the total group by the Early Cambrian.     

陕南寒武纪西乡生物群中Anabarites对称性演化研究

阿纳巴管(Anabarites)是寒武纪早期一类形态独特的管栖生物,其横切面的轮廓多样,但所有形态都是"3"的倍数。陕南梅树村期西乡生物群产出大量磷质Anabarites,根据管体上纵槽出现的数目和级别,确认Anabarites可分辨出三种对称类型:A型为仅具有三条一级纵槽的三辐射对称类型、B型具有三条一级纵槽和一条二级纵槽类型、C型具有三条一级纵槽和两条二级纵槽。其中B型、C型是从三辐射到六辐射对称之间的过渡类型,为新发现的对称形式。本文以上述三种类型Anabarites为研究材料,对Anabarites对称性演化途径进行了探索性研究,对寒武纪大爆发之初动物的对称性起源演化研究提供了重要证据。     

Traces of predation in the Cambrian

Series two marks a revolution in Cambrian predation when new predators and new predation methods appeared, which led to general increase in predation intensities and in the diversity of prey groups. The number of bored taxa and taxa with the predation scars is similar in the Cambrian. Most of the borings are associated with brachiopods and most of the scars with trilobites. Brachiopods, arthropods, molluscs, cnidarians and echinoderms were the most common prey in the Cambrian. The Cambrian record of predation is dominated by damage inflicted on brachiopods and trilobites. The fossils with predation signs are known from a majority of paleocontinents and all the Cambrian series.     

A statistical/computer-graphic technique for assessing variation in tectonically deformed fossils and its application to Cambrian trilobites from Kashmir

Hughes, N. C. & Jell, P. A. 1992 07 15: A stdlislical/compuler-graphic technique for assessing variation in tectonically deformed fossils and its application to Cambrian trilobites from Kashmir.
A combined approach using statistics and computer graphics can help resolve patterns of morphological variation in tectonically deformed fossils. Bivariate analyses and Principal Components Analysis can be used to identify a generalized strain vector in populations of deformed fossils, the identification of which permits discrimination of biological and tectonically induced variation. Results can be used to determine the number of taxa and growth relationships within the population. Statistically resolved taxa can be compared with species described from other areas using computer-aided shape restorations. Application of these techniques to a sample of trilobite cranidia from the Cambrian of Kashmir demonstrates that the variation of characters used to diagnose several genera and species are ontogeny- or deformation-controlled. Seven previously described species of Saukia, Prosaukia, Hundwarella and Anomocare are best considered as a single species, Hundwarella personara . These results suggest a Middle Cambrian age for the fauna, which has affinities with other faunas described from India and northern China. Hundwarella personara shows a pattern of developmental flexibility similar to that seen in other Cambrian trilobites. Morphometrics, computer-aided restoration, deformed fossils, allometry, trilobites, Cambrian, Kashmir, developmental flexibility .     

贵州中寒武世凯里生物群双刺吐卓虫(Tuzoia bispinosa)个体发育的研究

大型双瓣壳节肢动物是凯里生物群中重要组成部分,其中吐卓虫属（Tuzoia）最为常见,化石标本达200多件。吐卓虫常见于全球早、中寒武世地层,地理分布广泛,在地层对比和古环境研究中具有重要意义。文章运用数理统计和对比研究的方法,详细检测130多块双刺吐卓虫（Tuzoia bispinosa Yuan and Zhao,1999）化石标本,发现明显可分为幼年期、青年期和成年期3个不同的生长发育阶段。文中探讨双刺吐卓虫的个体发育,确认先前建立的凯里生物群中Tuzoia的2个种：Tuzoia bispinosa和T．magna,应为Tuzoia bispinosa一种。     

贵州剑河中寒武世中期甲劳组水母状化石的发现

贵州剑河革东镇八郎村南甲劳组中部钙质白云岩中新近发现的具有粗强放射状辐管的水母状化石和其下凯里组中具细辐管及同心环的拟轮盘水母(Pararotadiscus)有明显区别,属于伊尔东钵科(Eldoniidae)。其层位晚于中寒武世早期凯里生物群中拟轮盘水母(Pararotadiscus)层位1个化石带,属中寒武世中期,是该类化石在中国的最高层位,相当于北美布尔吉斯页岩生物群中Eldonia化石层位。     

Middle and Upper Cambrian Protoconodonts and Paraconodonts from Hunan, South China

More than 4200 kg of limestone, representing 980 productive samples, from the upper Middle Cambrian, Upper Cambrian, and lowermost Ordovician in western and north-western Hunan were processed for paraconodonts, protoconodonts, and euconodonts. The focus of the present paper is on the upper Middle and lower Upper Cambrian interval as it is developed at two, apparently stratigraphically continuous, key sections. The collections studied, which include more than 20,000 specimens and are quite diverse taxonomically, prove that some protoconodonts and paraconodonts are useful biostratigraphically. Previously proposed protoconodont-paraconodont biozones in Hunan are revised and correlated with recently revised trilobite biozones, as well as with protoconodont-paraconodont and trilobite biozones in North China. Twenty-six species and seven conditionally identified species belonging to 13 genera are described. Among these, two genera ( Huayuanodontus and Yongshunella ) and two species ( Westergaardodina elegans and Yongshunella polymorpha ) are new. This study has special interest for Cambrian biostratigraphy because the two studied sections are global stratotype candidates for the Middle-Upper Cambrian series boundary. The level of the Upper-Middle Cambrian Series boundary, as currently recognized in China (at the base of the Linguagnostus reconditus Trilobite Biozone) is well marked in the paraconodont succession and can be traced into the Swedish standard succession using these fossils. By contrast, another level recently proposed as a potential global Middle-Upper Cambrian Series boundary level, the base of the Glyptagnostus reticulatus Trilobite Biozone, does not coincide with any marked change in the Hunan conodont species succession useful for local and regional correlation.     

Early Cambrian radiolarians and sponge spicules from the Niujiaohe Formation in South China

Most of the reported Cambrian radiolarians are from middle Cambrian (Miaolingian Series, Wuliuan Stage) and onward, the radiolarians from lower Cambrian (Terreneuvian and Cambrian Series 2), on the other hand, are poorly documented, thus their morphological characteristics have not been well understood. In this study, we extracted spherical radiolarians and sponge spicules from the chert of the Cambrian Series 2 Niujiaohe Formation in southern Jiangxi Province, China. The well-preserved radiolarian fossils, identified as Paraantygopora porosa, consist of perforate plate shells pierced by dense pores with elevated rims, and display similarities to those from Lower Ordovician. Seven forms of sponge spicules are recognized, including monaxons, diaxons, tetractines, hexactines, triaxon tetractines, triaxon pentactines and irregular tetraxon tetractines, which are similar to those from the Qiongzhusian Stage in South China. Our results, combined with previously reported early Cambrian radiolarians from South China, indicate that the early Cambrian radiolarians developed advanced spherical skeletons.     

黔东早—中寒武世凯里组疑源类组合及其界线意义

通过对台江八郎和丹寨两条剖面凯里组中疑源类化石的分析,研究,台江剖面产疑源类化石有17属35各（12未定种）,其中以Leiosphaeridia,Synsphareidium,Cymatiosphaera,Pterospermella最为丰富,可划分为3个组合,即Cymatiosphaera cf.cristata-Fimbriaglomerella memebrancea组合,Cristallinium-Micrhystridium-Pterospermella组合和Dictyotidium-Granomarginata组合,丹寨平寨剖面凯里组所产疑源类化石有：13属21种（5未定种）,同样划分为3个组合,即Leiosphaeridia-Tasmanites组合,Retisphaeridium-Micrhystridium tentatium组合和Baltisphaeridium-Bubomorpha hunjiangensis组合,本文对两条剖面中的凝源类化石的组成,相对含量做了详细的统计,发现在八郎剖面9－2层和平寨剖面3层疑源类的丰度,分异度开始发生明显的变化,表现由早寒武世向中寒武世疑源类组合面貌的转变,这一疑源类转变层位正好是与三叶虫划分的中,下寒武统界线的层位位置相一致,这充分表明疑源类化石可作为划分中,下寒武统的极有价值的微体生物化石证据。     

寒武纪早期岩家河生物群:研究进展和展望*

埃迪卡拉纪-寒武纪转换时期动物的起源、演化和"寒武纪大爆发"一直是国际古生物学界研究的热点问题,其中寒武纪早期小壳化石群与埃迪卡拉纪化石群和寒武纪早期澄江化石库之间的内在关系是古生物学界研究的难题,其主要原因是寒武纪早期与小壳化石群伴生的宏体动、植物化石的缺乏。发现于峡东地区的寒武纪早期岩家河生物群填补了这一缺失环节,该生物群包含宏体动物、宏观藻类、小壳化石、球形化石(可能的胚胎化石)、微古植物和蓝菌类等化石,部分宏体化石显示了从埃迪卡拉纪向寒武纪过渡色彩。化石保存方式有碳质膜、黄铁矿化、磷酸盐化、硅化。因此对岩家河生物群生物多样性和埋藏学进行综合研究,将可提供纽芬兰世(梅树村期)碳酸盐台地—碳酸盐台地内部的局部凹陷盆地相的一个较完整的生物景观图,对探索"寒武纪大爆发主幕"前夕生物的辐射、演化模式及保存机制具有重要的科学意义。     

Divergence pattern of animal gene families and relationship with the Cambrian explosion

There are many gene families that are specific to multicellular animals. These have either diverged from ancestral genes that are shared with fungi and/or plants or evolved from an ancestral gene unique to animals. The evolution of gene families involved in cell–cell communication and developmental control has been studied to establish whether the number of member genes increased dramatically immediately prior to or in concert with the Cambrian explosion. A molecular phylogeny‐based analysis of several animal‐specific gene families has revealed that gene diversification by duplication occurred during two active periods interrupted by a long intervening quiescent period. Intriguingly, the Cambrian explosion is situated in the silent period, indicating that there is no direct link between the first burst of gene diversification and the Cambrian explosion itself. The importance of gene recruitment as a possible molecular mechanism for morphological diversity, and its possible role for the Cambrian explosion, are discussed. BioEssays 23:1018–1027, 2001. © 2001 John Wiley & Sons, Inc.     

Late Late Cambrian Trilobites From Near Birch Inlet, South-Western Tasmania

The first late Late Cambrian basinal-facies trilobites to be described from Tasmania are from a succession exposed 8.5 km west of Birch Inlet, south-western Tasmania. Twenty-one taxa are described; the six agnostoid species include a new species of Leiagnostus, L inletensis. The polymeroids include five new species: Hedinaspis uniformis, Proceratopyge longa, Niobella birchensisSkljarella expansa and Ivshinaspis reticulata.SkljarellaIvshinaspis are described for the first time from Australia. The specimens are preserved in siltstone belonging to a basinal facies; the fauna has more in common with those of the South-East China Faunal Province than with the shallow-water carbonate-facies faunas from northern Australia. The fauna is of late Late Cambrian age (Payntonian–earliest Datsonian) on the north Australian biostratigraphic scale. The Birch Inlet fauna is correlated with those of the Siyangshan Formation of Zhejiang, the Guoziguonen Formation of Xinjiang and the Shengjiawan Formation of Hunan. There are similarities with late Late Cambrian faunas from Nevada, Kazakhstan and New Zealand. K ey words : Trilobita, Late Cambrian, Tasmania, basinal facies, biostratigraphy, palaeobiogeography.     

A New Bivalved Arthropod from the Early Cambrian Sirius Passet Fauna, North Greenland

A new bivalved arthropod is described from the Lower Cambrian (?Upper Atdabanian) Buen Formation of North Greenland. Pauloterminus spinodorsalis gen. et sp. nov. possesses a bivalved carapace that covers the head, which has a single pair of antennae, and anteriormost thorax. No mouthparts are visible. The five‐segmented abdomen was limbless and terminated in a telson plus a pair of large, lobate uropods. A suite of at least six biramous thoracic limbs are present: the short endopods are made up of small, serial podomeres, while the exopods are lobate and may have functioned as gills as well as in swimming. Partially infilled guts are occasionally visible, suggesting that this animal may have been a sediment feeder. It is compared to other Cambrian bivalved arthropods, especially the waptiids Chuandianella ovata from the Lower Cambrian Chengjiang fauna (China) and Waptia fieldensis from the Middle Cambrian Burgess Shale (British Columbia). Of these three animals, the Greenland and Chinese taxa appear to be the most closely related. P. spinodorsalis possesses many typical arthropod features, but it also demonstrates more primitive characters that are more reminiscent of the lobopodians.     

Middle Cambrian cystoid (sensu lato) stem columnals from Bornholm, Denmark

A rich material of echinoderm fragments from two Middle Cambrian stratigraphical levels on Bornholm are preserved due to phosphatization of the original calcitic stereom. Preservation of echinoderms in this way - not previously recorded from the Middle Cambrian - permits detailed analysis of the three-dimensional stereom structure. Identifiable are fragments of stylophorans and eocrinoids. Stem columnals, most likely from eocrinoids, show a wide and advanced morphological variation indicating articulation similar to that of crinoids. The material from the Exsulans Limestone/Kalby marl ( Ptychagnostus gibbus Zone) represents stem-bearing cystoids older than Akadocrinus from Bohemia. The Andrarum Limestone ( Sole-nopleura brachymetopa Zone) contains echinoderm fragments from a higher stratigraphical level, a level correlatable with that from which the oldest North American stem–bearing cystoid, Eustypocystis , has been recorded.     

云南永善肖滩剖面早寒武世Lapworthella (托莫特壳类)骨片化石

描述了采自云南永善肖滩剖面下寒武统石岩头组的托莫特壳类(tommotiids)骨片化石Lnpworthella rete Yue,1987,其骨片锥状或塔状,横向环脊明显,环脊尖棱状;骨片外表面具多边形网状纹饰,但无齿、瘤或纵脊等装饰;骨片可分为两种类型,即弯曲型和近直立型,前者数量明显多于后者。简要地讨论了托莫特壳类化石的分类及生物亲缘关系,认为目前为止,其仍为亲缘关系不明的化石类别。尚难断定所有的托莫特壳类骨片化石皆属于同一生物门类,因为难以证明将它们归人同类生物所依据的骨片性状是共同衍征(synapomorphy)还是由于趋同演化(convergent evolution)的结果;在缺乏躯干化石记录的情况下,离散骨片的生物亲缘关系研究较为困难。     

A review of the Cambrian biostratigraphy of South Australia

Cambrian rocks in South Australia occur in the Stansbury, Arrowie, eastern Officer and Warburton Basins. The succession in the Stansbury and Arrowie Basins can be divided into three sequence sets (supersequences), 1, 2 and 3. Sequence set 1 can be divided into five third-order sequences: 1.0, 1.1A, 1.1B, 1.2 and 1.3. Trilobites from the Stansbury and Arrowie Basins are restricted largely to the lower part of the succession. Four trilobite zones are recognized: Abadiella huoi (latest Atdabanian–earliest Botoman), Pararaia tatei, Pararaia bunyerooensis and Pararaia janeae Zones (all Botoman). Trilobites higher in the succession are known from only a few horizons and in part correlate with the upper Lower Cambrian Lungwangmiaoan Stage of China, equivalent to the top Toyonian. Pagetia sp. has been reported in the Coobowie Formation of the Stansbury Basin, thus suggesting an early Middle Cambrian age.The Cambrian faunas of the Warburton Basin range in age from early Middle Cambrian (Late Templetonian) to very Late Cambrian, although the richest faunal assemblages are late Middle Cambrian (Ptychagnostus punctuosus to Goniagnostus nathorsti Zones). Conodonts, including Cordylodus proavus, occur in a Datsonian fauna.The Arrowie Basin contains the most complete and best studied archaeocyath succession in the Australia–Antarctica region. The Warriootacyathus wilkawillensis, Spirillicyathus tenuis and Jugalicyathus tardus Zones from the lower Wilkawillina Limestone (Arrowie Basin) and equivalents are correlated with the Atdabanian. Botoman archaeocyathids occur higher in the Wilkawillina Limestone. The youngest (Toyonian) archaeocyath fauna in Australia occurs in the Wirrealpa Limestone (Arrowie Basin).Brachiopods and molluscs of the Arrowie and Stansbury Basins can be divided into four biostratigraphic assemblages. Several informal Early Cambrian SSF biostratigraphic assemblages are recognized. Probable tabulate-like corals occur in the Botoman Moorowie Formation. Seven informal acritarch assemblages occur in the Early Cambrian of the Stansbury and Arrowie Basins. Trace fossils may mark the Precambrian–Cambrian boundary. Only two of several tuffaceous horizons from the Stansbury and Arrowie Basins have been dated (i) a date of 522.0 ± 2.1 Ma from the Heatherdale Shale of the Stansbury Basin, about 400 m above latest Atdabanian archaeocyathids and (ii) a date of 522.0 ± 1.8 Ma from the lower part of the Billy Creek Formation in the Arrowie Basin. Neither date is regarded as reliable.     

贵州寒武纪海绵动物化石组合特征

贵州寒武纪海绵化石丰富。分布广泛,主要产于早寒武世梅树村期的戈仲伍组或牛蹄塘组底部、筇竹寺期的牛蹄塘组和早、中寒武世凯里组。梅树村期的海绵属种单调,主要为六射海绵类麦粒海绵（Triticispongia sp．）及一些海绵骨针,代表寒武纪海绵首次爆发或辐射的前奏和先驱。牛蹄塘组海绵多达13个属,是寒武纪海绵辐射的重要窗口,以普通海绵略占优势,Leptomitus为优势属。凯里组的海绵共计7属,以普通海绵为主。贵州寒武纪海绵动物群的发展具有明显的阶段性和组成的差异性,其演变过程受到环境的制约。贵州早期海绵动物的发现和研究不仅改变了寒武纪生物多样性的认识,而且还为探讨海绵动物本身的起源、辐射提供了重要材料。