贵州中寒武世凯里生物群中宏观藻类化石新材料

贵州省台江县中寒武世凯里生物群含有丰富的非钙质藻类和具有软躯体后生动物化石,它为布尔吉斯页岩型生物群在世界广泛分布提供了更有力的证据。在生物群的宏观藻类中描述了5个属5个种。包括2个新属,它们是Marpolia spissa Walcott、Acinocricus stichus Conway Morris and Robison、Udotealga erecta Yang、Eosargassum sawata Yang和Rhizophyton zhaoyuanlongii Yang,并且将凯里生物群中的宏观藻类进行了对比,发现两个生物群不仅具有相似的动物化石组成,而且宏观藻类化石组成也很相似。     

贵州中寒武世早期凯里生物群研究的新进展*

贵州台江中寒武世凯里生物群的研究取得了突破性的进展 ,一些澄江生物群、布尔吉斯页岩生物群的分子诸如Ottoia,Naraoia,Palaeoscolex ,Urokodia,Microdictyon ,Leanchio lia,Isoxys及anomalocarids等化石已被发现 ,凯里生物群的组成发生了重大的变化。新面貌的凯里生物群成为拥有 1 2个大类 1 2 0多个属的布尔吉斯页岩型生物群 ,其中动物化石已超过 80多个属 ,仅次于布尔吉斯页岩生物群和澄江生物群 ,居全球同类型第三位。其核心组成为非三叶虫节肢动物、水母状动物及棘皮动物。     

贵州中寒武世凯里生物群中的蠕形动物化石*

描述了凯里生物群中的蠕形动物Ottoia ,Maotianshania ,Palaeoscolex ,Circocosmia?及Selkirkia。这些软躯体的蠕虫化石在凯里生物群中都是首次发现。其中Ottoia也发现于布尔吉斯页岩生物群 ,Maotianshania ,Circocosmia ?则见于澄江生物群 ,而Palaeoscolex则从澄江生物群至布尔吉斯页岩生物群中都有保存 ,这是凯里生物群处于承前启后位置的又一证据。蠕动动物的发现 ,增加了凯里生物群软躯体化石内容 ,反映了凯里生物群是典型的布尔吉斯页岩生物群。     

华南贵州寒武系(2-3统)凯里组有机质壁微体化石的新材料

凯里生物群既是中国华南寒武系重要的布尔吉斯页岩型生物群之一,同时也是国内外已知少数微体布尔吉斯页岩型特异埋藏化石库之一,化石以二维的有机质壁形式保存。本文改进孢粉学处理方法,对来自中国贵州寒武系凯里组苗板坡、丹寨、竹坪和屯州等几个剖面以及相邻地层的共22个样品进行酸泡处理,获得微体化石新材料。结果显示,苗板坡剖面保存的化石多样性明显较高,其中发现的疑源类和丝状藻类最多,占统计总数(N=1549)的90%以上;同时还发现少量的后生动物残片,如威瓦西虫的骨板、腕足动物壳体残块以及蠕形动物表皮等,这些后生动物化石残片为研究某些后生动物的细微结构提供了重要补充信息,有助于对这些动物化石进行分类鉴定,并可能具有一定生物地层学意义。     

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。     

埃迪卡拉纪至寒武纪苗岭世刺细胞动物化石研究现状与展望

刺细胞动物是一类具有刺细胞的水生无脊椎动物,分布在世界各地的海洋和淡水中。作为后生动物最早分化出的一支,刺细胞动物对研究后生动物的起源和早期演化具有极其重要的意义,也为研究后生动物系统发育、地层对比和古地理恢复等方面提供了重要的科研线索。本文简要介绍了刺细胞动物早期(埃迪卡拉纪至寒武纪苗岭世)的化石记录和研究现状,将刺细胞动物的早期演化分为四个时期,分别为前寒武纪、寒武纪纽芬兰世、寒武纪第二世和寒武纪苗岭世,并对上述四个时期的刺细胞动物进行论述。目前的研究表明:1)前寒武纪的刺细胞动物化石记录虽然比较丰富,但充满争议,目前尚未有比较确切的刺细胞动物记录;2)寒武纪纽芬兰世如宽川铺生物群中保存了较多的刺细胞动物胚胎及发育序列化石,是研究刺细胞动物演化的重要窗口;3)寒武纪第二世,以澄江生物群为代表的布尔吉斯页岩型化石保存了软躯体的刺细胞动物。与此同时,在第二世中已经出现了最早的珊瑚化石记录;4)寒武纪苗岭世刺细胞动物主要以布尔吉斯页岩型化石保存(如布尔吉斯页岩生物群和凯里生物群),同时期在美国犹他州发现的刺细胞动物印痕化石表明了这个时期几乎所有的刺细胞动物大类已经出现。本文根据上述时期的研究,对今后刺细胞动物化石的研究提供一些建议和讨论。     

贵州凯里生物群中的宏观藻类化石丘尔藻(Chuaria)及其意义

丘尔藻Chuaria Walcott,1899是宏观藻类中研究最早、延续时限最长的一类宏观藻类化石,它是新元古代赵家山生物群、淮南生物群及西陵峡动物群的代表分子之一.寒武纪第3世凯里生物群中Chuaria化石的产出,不仅是其最年青的代表,也是凯里生物群中宏观藻类组合中较为重要的分子之一.凯里生物群中Chuaria化石呈...     

湖北中部寒武纪早期石龙洞组布尔吉斯页岩型生物群的发现

文章简要报道湖北中部京山县郊发现的一个布尔吉斯页岩型生物群,该生物群由大量三叶虫、腕足类、软舌螺及少量鳃曳动物、双瓣壳节肢动物、非三叶虫节肢动物和棘皮动物等组成。文中重点描述非三叶虫节肢动物Clypecaris?和棘皮动物Sinoeocrinus,两者分别为澄江动物群和凯里生物群的典型分子。依据生物地层学证据,该生物群的时代大致为寒武纪第四期晚期(龙王庙期),与凯里生物群下部组合基本相当,稍晚于云南东部的关山动物群和峡东地区石牌组的布尔吉斯页岩型生物群。该发现进一步丰富了华中地区早-中寒武世化石库的资料,扩大了布尔吉斯页岩型生物群的地理分布,并是目前已知唯一的分布在扬子地台北缘的该类型生物群,这对寒武纪环扬子地台古生态的重建和多门类后生生物的演化都将提供重要资料。     

贵州江口桃映埃迪卡拉系陡山沱组中的三叶脊动物化石

本文描述的三叶脊类化石于2004年采自贵州东北部江口县桃映镇翁会村埃迪卡拉系陡山沱组上部庙河生物群,共2新属2新种:中国三射盘(新属新种)Triactindiscus sinensisgen.et sp.nov.及不规则似三角形盘(新属新种)Quasitriagondiscus irregularisgen.et sp.nov.。前者为大型盘状化石,具有3个呈碳质薄膜的长三角形叶脊,自盘体中央向边缘呈三辐射伸展,没有其它生物构造;后者为小型盘状化石,3条不规则叶脊在盘体中部形成似三角形并以此不同于其它三叶脊化石。庙河生物群2个三叶脊化石属相似于俄罗斯白海生物群的Albumares,Anfesta,Tribrachidium和澳大利亚埃迪卡拉生物群中的Tribrachidium,它们细节上有差异,但均属于埃迪卡拉系中三辐射对称的三叶动物。新的发现表明三叶动物在埃迪卡拉纪广泛分布于全球各地,也显示埃迪卡拉纪生物分异度比较高,辐射、两侧及三侧对称的动物均匀代表。贵州东北部江口桃映翁会庙河生物群含有丰富的宏观藻类及动物化石,如Protoconites,Cucullus,Sinospongia,Eoandromeda octobrachiata及新发现的2属三叶脊动物化石。江口庙河生物群组成上很相似峡东庙河生物群,也都位于陡山沱组上部黑色页岩中。江口庙河生物群不仅是整个庙河生物群的重要组成部分,也是埃迪卡拉纪生物演化的重要窗口。     

Fuxianospira gyrata和Morania fragmenta(宏观藻类)在华北寒武系馒头组的发现

本文描述了山东省临朐县龙岗村寒武系苗岭统乌溜阶馒头组上页岩段的宏观藻类化石,计2属2种:环圈螺旋抚仙藻Fuxianospira gyrata Chen et Zhou, 1997和碎片玛拉利亚藻Morania fragmenta Walcott, 1919。这两种藻类在大小和形态上可与布尔吉斯页岩和澄江生物群中的宏观藻类相比较。本研究通过探讨藻体的长宽比,认为M.fragmenta的碎片状形态可能是藻体本身生长而成的形态,而不是其命名者所认为的碎裂而成的形态。这两个属种首次在馒头组的发现,拓展了其时空分布,为华北地区寒武纪宏观藻类研究提供了较有价值的资料。     

New Macroalgal Fossils from Middle Cambrian Kaili Biota in Guizhou Province,China (in English)

Abundant and well-preserved remains of noncalcareous algae and soft-bodied metazoans were collected from Middle Cambrian Kaili biota in Taijiang county, Guizhou Province, China. These remains provide further evidence for the wide geographic distribution of many Burgess Shale taxa. Among the algae, 5 genera (including two new genera) and 5 species are described. They are Marpolia spissa Walcott, Acinocricus stichus Conway Morris and Robison, Udotealga erecta Yang, Eosargassum sawata Yang, and Rhizophyton zhaoyuanlongii Yang. Contrasting the macroalgal fossil assemblage in the Kaili biota with one in the Burgess Shale biota, it is clear that similarity of the Kaili biota and the Burgess Shale biota is reflected by the same content of not only the soft-bodied metazoans, but also the noncalcareous algae.     

贵州台江凯里动物群中的非钙质藻类化石

贵州台江凯里组的非钙质藻类化石在我国中寒武统尚属首次发现。国外主要见于北美。描述的非钙质藻类化石Ｍａｒｐｏｌｉａ ｓｐｉｓｓａ． Ｂｏｓｗｏｒｔｈｉａ ｓｉｍｕｌａｎｓ ,Ａｌｇａ ｇｅｎ． ｅｔ ｓｐ． ｉｎｄｅｔ, Ａ,Ａｌｇａ ｅｔｓｐ． ｉｎｄｅｔ, Ｂ等常见于北美布尔吉斯页岩动物群。当前中武寒武非钙质藻类化石的发现不仅填补了我国中寒武统非钙质藻类的空白,而且对于凯里动物群与布尔吉斯页斯     

贵州台江下-中寒武统凯里组遗迹化石群落与环境关系的探讨

通过贵州台江凯里组中丰富的、分异度较高的、以原地埋藏为特征的遗迹化石的研究,探讨凯里组遗迹化石群落的沉积环境和埋藏环境。凯里组遗迹化石群落以节肢动物和软体动物的停息迹、爬行迹和游泳迹占优势,浅层内生爬行觅食潜穴和系统觅食潜穴占有一定的地位,也见有浅的居住滤食性潜穴,属Seilacher的Cruziana遗迹相,为正常浪基面和风暴浪基面之间的浅海软质基底陆棚低能环境,那里盐度正常、光照充足、含氧量充分、水体平静、沉积速率较快。在此环境中,浮游、游泳以及底栖爬行和固着生物类型大量地生长、繁殖和活动,表生遗迹和浅层内生遗迹十分丰富。生物死亡后的腐烂和分解,使得食泥生物大量繁盛。随着沉积物的覆盖和被埋藏生物遗体的分解、腐烂,沉积物内部还原能力逐渐增强,导致分解和腐烂过程终止。     

凯里生物群腕足动物与游泳动物 共存现象研究

腕足动物是贵州凯里生物群中重要的化石门类,不仅化石数量丰富,分异度高,还具有丰富的生态现象。在寒武系的化石记录上,腕足动物常与海绵、藻类、棘皮动物、水母状生物、软舌螺、威瓦西亚虫、其他腕足动物等保存在一起,凯里生物群中的腕足动物也有类似的共存现象。本文就凯里生物群中腕足动物与游泳动物的共存现象进行了初步研究,认为腕足动物与贵州拟轮盘水母Pararotadiscus guizhouensis存在共栖、共埋两种关系,讨论了这两种关系的不同之处;分析了腕足动物与大型双瓣壳节肢动物加拿大虫Canadaspis的共存现象,推测一只腕足动物与Canadaspis共同保存的化石记录表明这两种生物存在共栖关系。本文的研究丰富了凯里生物群物种之间的生态关系,为凯里生物群的生态多样性提供了更多的证据。     

Benthic primary producers in exceptionally preserved Cambrian biotas of North China

Strata situated within the South China Craton host several key Cambrian macroalgal assemblages, including those of the Chengjiang, Kaili, and Tsinghsutung Lagerstätte. In this report, Cambrian macroalgae are described for the first time from the North China Craton, an area that, during the early Paleozoic, was not contiguous with the South China Craton. The material collected from the Mantou Formation and overlying Zhangxia Formation (Miaolingian Series) in Shandong Province is preserved as carbonaceous compressions and includes abundant simple tubular forms. These fall into two groupings on the basis of size and have characteristics broadly comparable to Fuxianospira gyrata and Sinocylindra yunnanensis, both of which are well-known from the Chengjiang biota and may represent simple siphonous green algae. Additional material includes irregular circular to oval films referable to Morania fragmenta and a tuft-like form superficially similar to Marpolia spissa, taxa with possible cyanophyte affinities described initially on the basis of material from the Burgess Shale but also known from the Cambrian of South China. The material is typical of the “Cambrian Flora” and provides further support for the cosmopolitan distribution of this noncalcified macroalgal flora at low latitude settings during the Cambrian.     

Skimming the surface with Burgess Shale arthropod locomotion

The first arthropod trackways are described from the Middle Cambrian Burgess Shale Formation of Canada. Trace fossils, including trackways, provide a rich source of biological and ecological information, including direct evidence of behaviour not commonly available from body fossils alone. The discovery of large arthropod trackways is unique for Burgess Shale-type deposits. Trackway dimensions and the requisite number of limbs are matched with the body plan of a tegopeltid arthropod. Tegopelte, one of the rarest Burgess Shale animals, is over twice the size of all other benthic arthropods known from this locality, and only its sister taxon, Saperion, from the Lower Cambrian Chengjiang biota of China, approaches a similar size. Biomechanical trackway analysis demonstrates that tegopeltids were capable of rapidly skimming across the seafloor and, in conjunction with the identification of gut diverticulae in Tegopelte, supports previous hypotheses on the locomotory capabilities and carnivorous mode of life of such arthropods. The trackways occur in the oldest part (Kicking Horse Shale Member) of the Burgess Shale Formation, which is also known for its scarce assemblage of soft-bodied organisms, and indicate at least intermittent oxygenated bottom waters and low sedimentation rates.     

Graptolite (Hemichordata,Pterobranchia) preservation and identification in the Cambrian Series 3

Due to inadequate preservation, pterobranchs are often difficult to identify in the fossil record, and a better understanding of preservational modes and diagenetic and metamorphic effects is needed for their recognition. Pterobranch hemichordates are common in Cambrian Stage 5 and younger sedimentary rocks, but are frequently overlooked. Often, pterobranch hemichordate colonies have been considered to be algal remains or hydroids. Re‐examination of Cambrian Burgess Shale algae reveals that the genera Yuknessia and Dalyia can be recognized as putative early representatives of pterobranch hemichordates. Distinct fusellar construction of the individual zooidal tubes and branching of the creeping proximal part of the colonies are found in the morphologically similar rhabdopleurid pterobranch genus Sphenoecium. The erect tubes of Sphenoecium do not branch and can reach a length of several centimetres. The development of the fusellar construction in this taxon shows a highly irregular development of the suture patterns, but a fairly consistent height of the individual fuselli. The taxon is widely distributed in the Cambrian Series 3, but has regularly been identified as a hydroid or an alga. Sphenoecium wheelerensis from the Cambrian Wheeler Shale of Utah is described as new.     

Annelids from the Lower Devonian Hunsrück Slate (Lower Emsian, Rhenish Massif, Germany)

Abstract:  Four new genera and species of annelid, Hunsrueckochaeta hohensteini , Ewaldips feyi , Crocancistrius lutzi and Scopyrites magnus , are described from the Hunsrück Slate (Lower Emsian) of Germany, as well as new material of Bundenbachochaeta eschenbachensis   Bartels and Blind, 1995 . The specimens preserve details of the appendages and other aspects of the morphology as a result of pyritization. A phylogenetic analysis using the morphological data matrix of Rouse and Fauchald places four of the five genera basal to the Aciculata; the fifth Ewaldips falls within the Scolecida. The diversity of annelids represented in the Hunsrück Slate is similar to that in the other major Palaeozoic Konservat-Lagerstätten that yield them, including the Cambrian Burgess Shale and the Late Carboniferous Mazon Creek biota.     

贵州台江中寒武世的一些软舌螺化石

该文的软舌螺标本采自贵州省台江县八郎村中寒武世地层,计有Haplophrentis?reesei,H.?carinatus,Hyolithes?cf.idahoensis,H.?cf.cariniferus,H.?sp.,Cambrovitus balangensis gen.sp.nov.,Notabititidae gen.et sp.uncertain.。其层位位于梅树村动物群和澄江动物群之上。地层时代与北美布吉斯页岩的时代相当,两地的软舌螺可直接对比。更为可贵的是在方Haplophrentis?carinatus的腹内视标本中发现了直肠和伸缩肌软体印痕。