New Maikhanellid Shells and Siphogonuchitid Spicule Bundles from the Cambrian Fortunian Stage of South China

Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the cap-shaped profiles and scaly shell ornamentation. According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia, we confirmed the family Maikhanellidae content of six genera, which are Maikhanella, Ramenta, Purella, Ramentoides, Yunnannopleura and Mediata. Unlike the halkieriid animals whose shells and spicules are articulated on different body parts, maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix (the "spicule shell" hypothesis), and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms. The affinities of Maikhanellids and siphogonuchitids remain debatable. Here, we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China. They differ from all the previously reported maikhanellids and siphogonuchitids, and may represent new types. The intact and smooth surface underneath the partially preserved scales of the shells challenges the "spicule-shell" hypothesis. The present siphogonuchitid spicules differ from the maikhanellid scales in size, morphology, and .arrangement pattern, thus the spicules might not be derived from the shells. Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.     

Genesis of Silica-phosphatic Nodules with Small Shelly Fossils Preserved in the Lowermost Cambrian of South China

Silica-phosphatic nodules are abundant in black shales of the Yanjiahe Formation in the Three Gorges Area of South China, which is correlated to the Fortunian Stage, Terreneuvian Series, Cambrian System. The nodules are rich in small shelly fossils and hence attract the attention of numerous paleontologists and sedimentary geologists. However, the genesis of the nodules and the preservation of the small shelly fossils are poorly understood. Here we analyze morphological, structural, mineralogical and chemical features of the nodules in multiscale using a combination of micro-X-ray fluorescence spectroscopy, X-ray diffraction, scanning electron microscopy and confocal laser Raman spectroscopy. Results reveal that nodules are concentric in chemical and mineralogical compositions, comprising a silica-phosphatic core encrusted sequentially by a phosphatic zone, a siliceous zone and a very thin pyrite outer rim. The black shales hosting the nodules demonstrate a laminated texture of alternating clayey and silty laminae, which were respectively deposited in sulfidic/less sulfidic, high/low production, intense/weak chemical weathering conditions. The phosphogenesis of the nodules resulted in the phosphatization of small shelly fossils, which prevented the fossils from being dissolved during diagenesis, whereas the silica encrustation sealed the fossils within the nodules and thus protected the fossils from alteration by deep burial and surface weathering.     

新疆阿克苏地区寒武纪幸运期早期小壳化石

本文报道新疆阿克苏地区寒武纪幸运期最早期的小壳化石组合。化石产自玉尔吐斯组底部,包括：Protohertzina anabarica Missarzhevsky, 1973、Protohertzina unguliformis Missarzhevsky, 1973、Anabarites trisulcatus Voronova and Missarzhevsky, 1969、Anabarites ternarius Missarzhevsky in Rozanov et al., 1969、Cambrotubulus decurvatus Missarzhevsky in Rozanov et al., 1969、Olivooides sp.、Kaiyangites novilis Qian and Yin, 1984以及海绵骨针化石。据此可以在新疆阿克苏地区玉尔吐斯组下部建立Anabarites trisulcatus-Protohertzina unguliformis组合带。该组合带下界以Anabarites trisulcatus、Protohertzina ungulifo...     

湖北宜昌滚子坳剖面寒武系幸运阶顶底界线

对湖北宜昌地区滚子坳剖面寒武系纽芬兰统幸运阶顶底界线的位置进行较为细致的研究.通过切片法及酸蚀法对61个样品进行系统处理,获得了大量的小壳化石、疑源类化石及其他分类位置未定化石.系统鉴定和描述了23属44种.根据具刺疑源类化石Asteridium和小壳化石Protohertzina sp.的首现位置以及无机碳同位素BA...     

三峡地区寒武系纽芬兰统岩家河组小壳化石研究进展

埃迪卡拉纪—寒武纪转换时期小壳化石的突然出现是世人瞩目的重要演化事件之一,它见证了动物的爆发式快速演化过程,标志着以两侧对称动物为特征的寒武纪生态系统的开始。湖北三峡地区寒武系纽芬兰统岩家河组处于幸运阶—第二阶这一关键层段,是研究上述问题的理想地区之一。岩家河组小壳化石研究最近取得的进展,为寒武系纽芬兰统幸运阶/第二阶界线的标定,和寒武纪早期软体动物和刺胞动物的演化及个体发育提供了重要的化石依据,本文对其进行了总结。全球界线层型剖面和点位(GSSP)寒武系第二阶底界划分标志的Watsonella crosbyi和Aldanella attleborensis在岩家河组第5段底部的同时出现,意味着岩家河组第5段已归属寒武系第二阶。这两类软体动物化石均广泛分布于华南、蒙古、西伯利亚和北美等大陆碳酸盐岩相寒武系第二阶地层中,它们均是定义寒武系第二阶底界的有力竞争者。另外,W.crosbyi壳顶下方一对肌肉附着结构的发现提供了重要的软组织结构信息,证实了W.crosbyi为内腹型壳,归属为未扭曲的软体动物太阳女神螺类。新发现六方锥石类Septuconularia yanjiaheensis具侧向压扁、两辐射对称的、14个等大锥面的围鞘,是迄今所描述的六方锥石类中锥面数最多的类型。根据横肋疏密程度,围鞘由下向上可分为三部分,可能代表胚胎期、幼年期和成年期不同的生长阶段。Septuconularia显然由寒武系幸运阶Hexaconularia通过扇面扩增演变而来,证明Hexaconularia可能是Arthrochites和Septuconularia之间的中间过渡类型。新发现的橄榄蛋类Octapyrgites elongatus与幸运阶Olivooides和Quadrapyrgites十分相似,围鞘由方形的壳顶区和波纹状倒宝塔形的远顶区组成。然而Octapyrgites只有8个口折叶,有别于具12个口折叶的Quadrapyrgites。通过与幸运期水母类多种对称方式对比,发现在寒武系第二阶橄榄蛋类数量减少和五辐射对称骨状壳类缺失,表明在幸运期/第二期转换时期,底栖固着型的刺胞动物水母类多样性发生了明显衰落,甚至部分绝灭,而同期的两侧对称动物则迅速辐射演化。     

A New Species of Septuconularia (Hexangulaconulariidae, Cnidaria) from Cambrian Stage 2, South China

Hexangulaconulariids, an extinct family of medusozoan small shelly fossils (SSFs), were a conspicuous component of early Cambrian, shallow marine platform communities in South China. Described herein is Septuconularia crassiformis sp. nov. from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) in the Three Gorges area of Hubei Province. The new species differs from the type and only other known species, S. yanjiaheensis, in the shape of the abapical portion and in the degree of curvature of the adapertural margin. The anatomy of the apical portion of the new species is unknown. The diagnosis of the genus Septuconularia is emended and the spatio-temporal distribution of hexangulaconulariids in South China is summarized. Finally, S. yanjiaheensis, with its slit-like aperture and very narrow transverse cross-section, may have been better adapted to the shallow platform environment than the broader S. crassiformis, which appears to have been less common than the type species.     

Tommotian (Lower Cambrian) stratigraphy and fossil fauna communities in the Kiya River section (Kuznetsk Alatau)

The lower Ust’-Kundat Formation has been studied in detail in a section along the Kiya River (Kuznetsk Alatau, Altai-Sayan folded area). The section was deposited during the Tommotian stage and is a stratotype for the Lower Cambrian Ust’-Kundat sequence comprising several members of the Ust’-Kundat Formation. Member 2 contains newly discovered and previously known species of archaeocyathids near its top found stratigraphically lower than the oldest known archaeocyathan assemblage of the Nochoroicyathus mariinskii biozone. The found archaeocyaths cannot be dated precisely and may have either Tommotian or Atdabanian ages. Small shelly fossils from the same section cover a large stratigraphic range as well. The findings call for updating the age of the upper Ust’-Kundat sequence and the Tommotian upper boundary in the regional stratigraphy of the Altai-Sayan folded area.     

台江阶——我国寒武系一个新的年代地层单位

台江阶是继湘西建立的 4个中 -上寒武统新阶之后在我国江南斜坡带黔东传统的中寒武统下部建立的又一个新阶 ,它的底界层型剖面位于贵州台江县革东镇八郎村 ,底界划在 Oryctocephalus indicus的首现位置 ,位于凯里组下部第 10层之底。     

Furongian (upper Cambrian) Guole Konservat-Lagerst?tte from South China

The Guole biota contains common shelly fossils and some exceptionally well-preserved soft-bodied fossils. Stratigraphically, it is located in the mudstones and siltstones of the Sandu Formation near Guole Town, Jingxi County, Guangxi, South China. It is the first Furongian (late Cambrian) Burgess Shale-type biota found in the world, thereby filling the gap between middle Cambrian and Lower Ordovician Burgess Shale-type Lagerst?tten. Preliminary studies suggest that the Guole biota includes approximately seven metazoan groups as well as algae. These will provide important new evolutionary and ecological information.     

内蒙古商都白云鄂博群小壳化石的发现及其意义

根据研究清河镇化石群提供的信息,在内蒙古商都五道湾地区白云鄂博群阿牙登组下部首次发现梅树村阶小壳动物化石,内含软舌螺类、似软舌螺类、齿形壳类、棱壳类、卡门壳类等８属８种（含１相似种,２未定种）及大量海绵骨针,共计２０００余件。确定白云鄂博群的地质时代为震旦纪一寒武（奥陶）纪。再次证明了清河镇化石群的存在;验证了氢氟酸法是提取浅变碳酸盐岩中化石的有效方法;并提出加里东褶皱带的新设想。     

New Bivalved Arthropods from the Cambrian (Series 3, Drumian Stage) of Western Hunan,South China

We report two new three-dimensionally phosphatized microfossils, Cambrolongispina reticulata gen. et sp. nov. and Cambrolongispina glabra gen. et sp. nov., from the middle Cambrian （Series 3, Drumian Stage） at Wangcun, Yongshun County, western Hunan, South China. They are bivalved arthropods, with thin, pliable, originally chitinous or chitin-calcareous shields （c. 350-517 I1 m long）. The shields are equipped with a pair of antero-dorsal spines. The spines are internally hollow, varying in length from 1/2 of to as long as the shield length in C. reticulata, and uniformly longer than the shield length in C. glabra. The spines of C. reticulata are ornamented with a longitudinal row of conical or blade-shaped denticles along the posterior edge. Cambrolongispina lacks marginal rims, valve lobation and sulci which are diagnostic of the Bradoriida sensu stricto. It also lacks a donblure/duplicature characteristic of phosphatocopids and some bradoriids. It could be related to the Monasteriidae （which may belong to Bradoriida sensu lato）, both characterized by a pair of antero-dorsal spines. Cambrolongispina may have been meiofaunai detritus feeders that lived on or within sediments. The antero-dorsal spines may have been sensory organs to detect nearby predators. The posterior denticles on these spines might have facilitated the sensory function of the spines.     

全球寒武系第4阶国际层型剖面及点位(GSSP)研究的进展

赵元龙研究团队以贵州剑河交榜杷榔组剖面为依据,结合其下变马冲组及其上“清虚洞组”于2010年起进行了长达10多年的寒武系第4阶地层、层序地层、碳硫同位素等学科的研究,取得了明显的进展,建立了3个三叶虫带及1个三叶虫层位、2个疑源类组合带,初步确定首现于杷榔组底部的Oryctocerella duyunensis为第4阶首现三叶虫。疑源类、碳硫同位素等变化曲线与此基本一致。并与北格林兰Henson Gletscher地层进行了对比,将视剑河交榜杷榔组剖面为潜在的寒武系第4阶国际层型剖面及点位(GSSP),将继续进行深入研究。     

A New Platy-armored Worm from the Early Cambrian Chengjiang Lagerstatte, South China

The Lower Cambrian Chengjiang Lagerstatte provides a good window to explore the origin and radiation of early bilaterians. Here we describe a netted sclerite-bearing worm Tabelliscolex hexagonus gen. et sp. nov., and tentatively assign it to palaeoscolecidans of priapulids. The cuticle of the animal is covered with two kinds of platy sclerites which are constructed by hexagonally arranged tubercles. Similar structures of the sclerites can be seen on some Cambrian palaeoscolecidans and lobopods, so, this new species is critical for understanding the relationships between lobopods and palaeoscolecidans.     

New Record of Palaeoscolecids from the Early Cambrian of Yunnan, China

A new palaeoscolecid, Guanduscolex minor Hu, Luo et Fu gen. et sp. nov., with preserved soft parts of introvert and intestines comes from the Lower Cambrian Guanshan fauna of Yunnan, South China. Microstructural details of the cuticle revealed by scanning electron microscopy （SEM） show that each annulation bears three rows of plates and each plate bears 9-10 marginal and 4-5 central nodes. This discovery sheds new light on the relationships and evolutionary pathway of the palaeoscolecids and other early priapulids.     

A New Vetulicolian from the Early Cambrian Chengjiang Fauna in Yunnan of China

The genus and species Yuyuanozoon magnificissimi gen. et sp. nov., a new fossil vetulicolian, is reported from the Early Cambrian Chengjiang Fauna in Yunnan of China. It has a bipartite body plan and five pairs of chain-formed gill sacs, showing the general characteristics of Ventulicolia. However, the exclusive "atrial cavity" and external gill observed indicate that the new form is different from those previously described as vetulicolians, probably representing a lineage developed within deuterostomes and more primitive than urochordates.     

贵州遵义寒武系底部硅质岩中细菌状化石的发现

通过扫描电镜精细观测,在贵州遵义松林地区早寒武世黑色岩系剖面,于其底部的硅质页岩中发现了可能的细菌状化石,直径200～500 nm,形态不一,具有细菌的大小和形状,有机碳含量丰富,大部分细菌含磷.通过与已有报道中具相似形态生物体的对比,认为其可能是原生的、具有细菌生物结构的微生物小球体(Microbioids),本文称之为细菌状化石.这类细菌状化石可以赋存于石英颗粒表面、石英颗粒间,甚至嵌入石英颗粒中.据前人的模拟实验推测,细菌在石英颗粒沉淀过程中可能起到过重要促进作用,这从微观上为硅质岩的形成提供了新信息.     

New Localities and Palaeoscolecid Worms from the Cambrian (Stage 4, Series 2) Guanshan Biota in Kunming, Yunnan, South China

The Guanshan Biota from the Cambrian Stage 4 Wulongqing Formation is a typical Burgess-shale type Lagerst?tte that had witnessed the Cambrian explosion. Here we report two new localities of the Guanshan Biota, which is located at Baimei village, south of Kunming and Xinglong village, Wuding County, Yunnan Province respectively. Both localities produce soft-body fossils and several new taxa, e.g. a new species of palaeoscolecidans (Palaeoscolex xinglongensis sp. nov.) reported herein. The comparative study of the new species with similar form not only indicates that there is a diversification of palaeoscolecid species in Guanshan Biota, but also strengthens the ties between the older Chengjiang Biota and the younger Kaili Biota (and also the coeval Burgess Shale community). Three paleoecological features, including high diversity, little disparity and richness of palaeoscolecid worms, are summarized as a case study to represent the differences between Guanshan and Chengjiang Biota.     

New Bradoriid Arthropods from the Early Cambrian Balang Formation of Eastern Guizhou, South China

The Early Cambrian Balang Formation is comprised of mudrock and shale, which was deposited in a shelf environment in the eastern part of Guizhou, south China. The Balang Fauna, which consists of seven phyla, occurs in the middle and upper parts of the Balang Formation. Arthropods are important constituents of the Balang Fauna and include a great number of trilobites, large bivalved arthropods, and newly-discovered well-preserved bradoriid fossils. The bradoriids present include three genera and four species : Comptaluta inflata (Cheng, 1974) emend Hou et al., 2002; Comptaluta kailiensis sp. nov., and Alutella elongeta sp. nov., Aluta sp. This faunal assemblage in the Balang Formation is distinguished from the Tsunyiella Chang, 1964, Songlinella Yin, 1978 and Kunmingella Hou, 1956 assemblage which occurs in the Niutitang and Mingxinsi formations of the Yangtze Platform in middle region of Guizhou and which is earlier than the Balang Formation in age. However, this assemblage resembles the Comptaluta pik, 1968 assemblage from the Early Cambrian Heilinpu Formation in Wuding County, Yuanan Province and from the Ordian Stage of the Cambrian of Australia. The great abundance of Comptaluta pik, 1968 and overall taxonomic diversity of the Comptaluta pik, 1968 assemblage set it distinctly apart from the Alutella Kobayashi et Kato, 1951 and Aluta Hou, 1956 assemblages of the Balang Formation. Alutella Kobayashi et Kato, 1951 and Aluta Hou, 1956 also occur in the Early Cambrian Niutitang Formation of the Yangtze Platform of Guizhou. Individual Bradoriids from the Balang Formation are characterized by large size (3 mm). The discovery of new Bradoriid assemblages not only expands the group’s geographical range and assemblage affinities, but also indicates that Bradoriids migrated eastward from shallow-water to deeper-water environments during the Early Cambrian, indicating that they were capable of life in deeper-water, and adaptation to a new ecological setting.     

华南早寒武世黑色岩系镍钼多金属矿床矿物学特征研究

湖南张家界三岔和贵州遵义黄家湾在下寒武统黑色岩系中发育有镍钼多金属矿床,这是华南乃至全球这类矿床的2个典型实例。通过对其进行系统的矿相显微镜、电子探针以及扫描电子显微镜观测分析,分析了成矿岩系的矿物学特征,并进一步根据矿物结构、组成与共生关系,结合地质背景,讨论了矿床成因。结果显示,非矿层中的金属矿物类型较为单一,主要是黄铁矿;而矿层中发现的矿物种类丰富,主要包括＂碳硫钼矿＂、针镍矿、黄铁矿、胶磷矿等,其中＂碳硫钼矿＂和针镍矿分别是钼与镍的主要赋存形式。认为钼主要来自于海水,镍主要来自于热水（液）流体,矿床为海水-热水（液）-生物复合成因。这些研究结果为此类矿床研究提供了新的矿物学基础研究资料,并且有助于加深对矿床成因的认识。     

A New Ichnogenus Kailidiscus Produced by Attachment from the Middle Cambrian Kaili Formation in Taijiang, Guizhou Province, China

Over 190 specimens of an attachment ichnofossil Kailidiscus （n. ichnogen.） have been found in the Kaili Bitoa, a Burgess Shale-type biota, from the middle Kaili Formation （early Middle Cambrian） in Taijiang County, Guizhou Province, southern China. Kailidiscus is an epichnia with a circular to oval attachment platform, on which there is a carbonaceous film probably formed by the body of the living organism. Structures such as a marginal furrow, an inner and outer marginal ride, many convex fold-ridges, and a large caved peripheral furrow on the attachment platform may be the result of basal tissues of a sessile organism that wrinkled to increase the attachment＇s surface area. The Kailidiscus organism may have been a sessile cnidarian attached to the muddy seafioor. Kailidiscus organisms lived in relatively quiet water, and were buried by a sudden influx of sediment.