论粤、桂、湘、鄂二叠纪有孔虫的组合特征

一、前言世界若干地区有关二叠纪非(虫莛)有孔虫(下简称有孔虫)的研究已有百余年的历史,但至今大多限于化石形态、构造及分类上的研究。近年来,海相二叠纪含油、气层的发现,其中富含的有孔虫化石越来越引起人们的注意,特别是有孔虫的生态以及迄今尚未详细研究的二叠纪各时期有孔虫组合特征,均有必要深入进行综合分析,以适应当前石油地质科学发展的需要。我国华南地区海相二叠系的分布极广,并含十分丰富的有孔虫,是研究二叠纪有孔虫     

从鄂西二叠纪碳酸盐岩微相探讨有孔虫的生态环境

鄂西二叠纪的有孔虫类极为丰富，几乎产于各类碳酸盐岩中。其系统演化快，地理分布广，因此对其生态环境的研究，对于恢复古海域各种沉积环境，具有较大的意义。我国对二叠纪有孔虫的研究多则重于分类学和各地层单位中有孔虫组合特征及其地层学意义方面，而对有孔虫生态还很少有系统的研究。傅瑜(1979)应用有孔虫和藻类分布特征探讨四川盆地阳新世沉积条件就是一种尝试。笔者拟从碳酸盐岩岩石学、岩相古地理学、化石岩石学等方面入手，通过对碳酸盐岩微相环境的分析，与碳酸盐岩中的有孔虫组合特征及其形态结合起来，探讨二叠纪有孔虫的生态环境。 鄂西二叠纪的有孔虫类极为丰富,几乎产于各类碳酸盐岩中。其系统演化快,地理分布广,因此对其生态环境的研究,对于恢复古海域各种沉积环境,具有较大的意义。我国对二叠纪有孔虫的研究多则重于分类学和各地层单位中有孔虫组合特征及其地层学意义方面,而对有孔虫生态还很少有系统的研究。傅瑜(1979)应用有孔虫和藻类分布特征探讨四川盆地阳新世沉积条件就是一种尝试。笔者拟从碳酸盐岩岩石学、岩相     

江西乐平沿沟二叠纪末有孔虫的演变及对鲕状灰岩的古环境指示意义

江西乐平沿沟剖面均一的碳酸盐相岩沉积, 完整地记录了二叠系-三叠系界线附近生物演变过程.通过对该剖面系统的化石切片研究, 共鉴别出有孔虫27属39种, 包含类4属7种.该剖面有孔虫的演变在二叠纪-三叠纪之交呈现出单幕式的消减过程, 对应于华南两幕生物灭绝中的第1幕.有孔虫的个体数和多样性在21-2层顶部发生了突然降低.4个不同有孔虫组合的演替关系, 揭示了有孔虫在灭绝事件中的演变过程, 即由灭绝前的高丰度、高分异度组合转变为灭绝后低丰度、低分异度组合.通过对二叠系-三叠系界线处鲕状灰岩的化石和沉积特征研究, 发现Hindeodus changxingensis带内的鲕状灰岩中仍存在较为丰富的有孔虫等化石.剧烈的海平面变化以及鲕状灰岩形成使下伏地层中的化石颗粒发生再沉积作用, 是形成这一特殊现象的主要原因.通过对鲕状灰岩中化石和沉积特征的深入研究, 论证了该鲕状灰岩形成于二叠纪-三叠纪之交大灭绝之后, 是当时特殊的海洋生态系产物, 反映了当时较高的海水回旋速率、微生物繁盛、海水碳酸盐超饱和等异常的环境条件.      

有孔虫壳体内草莓状黄铁矿成因及其地质意义——以湖北雁门口地区栖霞组有孔虫化石为例

在湖北省京山县雁门口地区栖霞组上部的含泥灰岩中存在丰富的节房虫科底栖有孔虫化石,主要有节房虫属、厚壁虫属和郎格虫属,壳体均被草莓状黄铁矿充填。对其系统的显微镜、扫描电镜观察和黄铁矿的能谱分析结果发现,黄铁矿草莓体直径最大为15 μm,平均约10 μm,硫铁原子比值（S/Fe）为1.90±0.10,表明在黄铁矿形成过程中,有孔虫壳体空腔内呈轻度- 中度贫氧的微环境。在分析该类黄铁矿成因的基础上,认为有孔虫壳体内的黄铁矿在指示沉积环境和保存环境方面具有局限性。     

安徽萧县白土剖面有孔虫动物群研究

实测描绘了安徽萧县白土镇石炭纪—早二叠世的地层剖面,对剖面中采集的样品进行了磨片,并在偏光显微镜下对磨片进行了系统鉴定,共鉴定出9科16属34种,且进行了系统的描述。建立了有孔虫化石组合带Tetratax-is-Nodosaria-Palaeotextularia组合带,为晚石炭世晚期(C22)。将研究区内的有孔虫化石组合带与国内不同地区有孔虫化石组合带进行了对比,探讨了石炭纪—早二叠世有孔虫化石在地层中的分布特征,探讨了有孔虫化石对地层划分对比中的作用,认为有孔虫化石对于石炭—二叠纪的地层界线也有重要的意义。     

山东淄博太原组有孔虫及石炭系与二叠系界线

通过对山东省淄博地区太原组小有孔虫类动物群的系统研究,共鉴定出小有孔虫11属22种及部分未定种。根据有孔 虫类化石在地层中的分布和垂向变化规律,建立了两个小有孔虫化石组合带：IBradyina-Plectogyra 组合与IITetrataxisNodosaria-Palaeotextularia 组合。通过与邻区及华中华北其它地区的有孔虫进行对比,并结合前人对本区 类化石的研究结 果,确定了各组合带的地质时代：太原组小有孔虫动物群第I组合带地质时代归为晚石炭世,第II组合带地质时代归为早二 叠世,其层位相当于山东地区太原组 类Pseudoschwagerina带之底。     

罗平生物群

<正>罗平生物群是目前已知多样性最为丰富的中生代海生化石库之一,代表二叠纪末生物大绝灭后早三叠世海洋生态系统的全面复苏。罗平生物群是海生动物、陆生植物以及少量陆生动物的混合群落。其中,节肢动物占主宰地位,以甲壳纲为主,还有鲎类、千足虫类等。鱼类也丰富多样,至少有二十多个种,其中大部分是新属新种。伴生化石还包括海生爬行类、双壳类、腹足类、菊石、棘皮类、腕足类、牙形石、有孔虫等。罗平生物群保存     

Gallowayinella的时代——兼论长兴阶与吴家坪阶的分界

<正> 陈旭教授1934年建立Gallowayinella属,是纪念美国有孔虫学者Galloway的。初发表时称为Gallowaiina,1937年被Dunbar和Skinner改为Gallowaiinella。1964年,Thompson指出这两个属名的拼法都有缺陷,把Galloway的最后一个字母变成“i”,与国际动物命名法32条a(ii)和c的规定不符,应予改正。但如果机械地改成Gallowayina,则此名又早在1932年被有孔虫圆片虫类(orbitoid)的Gallowayina Ellis所占用。因此,Thompson(1964)将其改成Gallowayinella,并认为符合国际动物命名法56条a的规定的。     

罗平生物群

<正>罗平生物群是目前已知多样性最为丰富的中生代海生化石库之一,代表二叠纪末生物大绝灭后早三叠世海洋生态系统的全面复苏。罗平生物群是海生动物、陆生植物以及少量陆生动物的混合群落。其中,节肢动物占主宰地位,以甲壳纲为主,还有鲎类、千足虫类等。鱼类也丰富多样,至少有二十多个种,其中大部分是新属新种。伴生化石还包括海生爬行类、双壳类、腹足类、菊石、棘皮类、腕足类、牙形石、有孔虫等。罗平生物群保存     

罗平生物群

<正>罗平生物群是目前已知多样性最为丰富的中生代海生化石库之一,代表二叠纪末生物大绝灭后早三叠世海洋生态系统的全面复苏。罗平生物群是海生动物、陆生植物以及少量陆生动物的混合群落。其中,节肢动物占主宰地位,以甲壳纲为主,还有鲎类、千足虫类等。鱼类也丰富多样,至少有二十多个种,其中大部分是新属新种。伴生化石还包括海生爬行类、双壳类、腹足类、菊石、棘皮类、腕足类、牙形石、有孔虫等。罗平生物群保存     

Numerical Taxonomy and Bayes Discriminant Analysis on 42 Fossil Species in Dicksoniaceae from China

As the basal group of Polypodiales, the specific taxonomy of Dicksoniaceae is still being debated. As aquantitative analysis method, numerical taxonomy has been applied to the taxonomic study of many plant families andgenera in recent years due to its simplicity and high accuracy. However, the numerical analysis of the Dicksoniaceae fossilshas not been reported at present. In the present study, the pinnule morphological data of 42 Mesozoic fossil species of theDicksoniaceae were analyzed using cluster analysis, principal component analysis and correlation analysis. The resultsrevealed that 42 taxonomic units could be divided into six representative groups, which are consistent with the traditionaltaxonomy. After screening, an identification key on 28 fossil species of four genera with a definite taxonomic position wasestablished. According to the quantitative analysis, a Bayes discriminant model was established for the selected species.Lastly, the model was tested using the morphological data of the fossil pinnules in Dicksoniaceae from the YaojieFormation, suggesting that the discriminant model is accurate to a certain extent. As a result, the numerical taxonomy canbe applied to the classification of the Dicksoniaceae fossils.     

Vestrogothia spinata (Phosphatocopina, Crustacea), Fossils of Orsten-type Preservation from the Upper Cambrian of Western Hunan, South China

Abstract: Fossils of Orsten-type preservation represented by the crustacean Skaracarida and Phosphatocopida were found in western Hunan, South China in 2005, including the important phosphatocopid species Vestrogothia spinata based on exquisitely preserved soft-bodied specimens that allow the first growth stage to be reestablished. The taxonomy of Vestrogothia spinata is revised employing the character of a two-divided limb stem of the mandible. A new foundation for the phylogeny of the Phosphatocopina using mandible characters related to crustacean appendages is postulated. Vestrogothia spinata has only previously been found from Sweden.     

Quantitative taxonomy and biostratigraphy of Middle Cambrian trilobites from Montana and Wyoming

This study was made to revise the taxonomy and biostratigraphy of Middle Cambrian trilobites from Montana and Wyoming. Both numerical and conventional analyses were made of the taxonomic and biostratigraphic data. Numerical taxonomy was performed on a sample of 210 OTU's (Operational Taxonomic Units) using 66 characters which were determined on cranidia of Middle Cambrian ptychopariid trilobites. These characters consisted of linear measurements which were transformed to indices proportional to glabellar length, quantitative-qualitative shape or angle measurements, and multistate attributes. The similarity coefficients calculated were average taxonomic distances and Pearson's product-moment correlation coefficient. The matrices of similarity coefficients were clustered by single-linkage and unweighted pair-group algorithms. The coordinates of OTU's in a three-dimensional A-space defined by the first three principal axes also were calculated. A phenogram of the distance matrix clustered by UPGMA (which yielded the highest cophenetic correlation coefficient) and a three-dimensional pin-and-ball model were used to interpret the trilobite taxonomy. Insufficiently clear clustering in both representations of taxonomic structure necessitated also a conventional taxonomic study guided by the numerical phenetics. Numerical biostratigraphy was performed with 79 collections as OTU's and 43 trilobite genera as characters. Jaccard coefficients were used as similarity coefficients, and the results were clustered by UPGMA. The resultant phenogram was readily interpretable, and seven faunal assemblage zones (Albertella, Glossopleura, Ehmaniella, Bolaspis-Glyphaspis, Ehmania, Parehmania, and Bolaspidella)are defined for the Middle Cambrian in the study area. Two of the zones (Ehmaniellaand Parehmania)are new and replace part of the previously defined “Bathyuriscus-Elrathina”zone. Bolaspis-Glyphaspis, Ehmania,and Parehmaniazones may have only regional validity.     

Numerical classification applied to certain Jamaican eocene nummulitids

Eighty-eight specimens of Eocene nummulitids from the Yellow Limestone Formation of northwestern Jamaica are classified according to quantitative measurements of morphologic parameters that are generally considered to be taxonomically useful. The specimens are grouped into homogeneous classes by the computer screening of differently oriented data projections. By this method, the use of similarity coefficients and the question of a priori weighting of characters, for which numerical taxonomy has been heavily criticized, are both avoided. The stability of the classes thus obtained is validated by discriminant analysis. These techniques provide an objective view of phenetic differences among specimens and show how the measured characters produce those differences. Tightness of coiling and total number of whorls, prove to be the most useful features in discriminating between groups but seem to have taxonomic value only at the specific and not at the generic level. This suggests that the generaOperculinoides andNummulites are synonymous.     

Phylogeny of transfer RNA and origins of organelles

By using nucleotide sequences of transfer RNA's, the endosymbiotic model for the origin of chloroplasts and mitochondria is examined. The endosymbiotic origin of the chloroplasts is confirmed, but concerning the origin of the mitochondria no conclusion can be drawn. Phyletic relations of euglenoids to higher plants and to animals are also discussed. Finally, phylogeny of fungi is discussed in terms of tRNA sequences and it is proposed that the classical taxonomy of fungi should be reconsidered in terms of molecular taxonomy or molecular paleontology.     

THE PROBLEM OF TRANSITION IN PALEONTOLOGY

The author equates paleontology and phylogeny and discusses principles and problems of transitions found in the phylogentic approach to taxonomy. opics discussed include: subspecies and species (time needed for new species to become isolated is 500 to 1,000 years); the morphological exclusiveness of genera in the differential diagnoses of species, evolutionary patterns of transition in time, the biogenetic law (“Ontogenesis in compressed form reflects the phylogeny of a long series of ancestors, retaining everything that was especially useful for life, but preserving in it generalized form, without the details characterizing the adult states”); ability of changes in early ontogenetic stages to produce sudden large phylogenetic changes, and monophyletic and polyphyletic evolution. — R. S. Boardman.     

Phylogeny of Devonian Lycopsids Inferred from Bayesian Phylogenetic Analyses

To investigate the phylogeny of early lycopsids, cladistic analyses using both parsimony and Bayesian approaches are presented, with a data matrix of 33 morphological characters across 25 taxa. The resulting parsimony and Bayesian trees showed overall similarities in tree topologies. In the Bayesian tree, the Protolepidodendrales and the heterosporous lycopsids are recognized as two monophyletic groups, and within the latter group, the Isoetales sensu lato forms a subclade. This topology implies that the acquisition of a ligulate character evolved twice in the lycopsids, once in the protolepidodendralean Leclercqia Banks et al., and once in the heterosporous lycopsid clade. Phylogenetic positions of several lycopsid plants previously reported from the Mid-Upper Devonian of South China, which have uncertain ordinal affinities, were estimated by the cladistic analyses; cf. Longostachys Xue et Hao, Longostachys Zhu et al., Monilistrobus Wang et Berry, and Yuguangia Hao et al. fall well within the Isoetales clade, as earliest members of this order, while Minostrobus Wang and Wuxia Berry et al. are nested within the basal part of the heterosporous lycopsids. Bayesian analyses are a very useful approach in systematic studies and can be applied in analyzing paleobotanical data sets as well.     

中国的伤齿龙类恐龙化石

伤齿龙类是手盗龙类中较为独特的一支, 时代从中侏罗世到晚白垩世, 主要分布于亚洲(东部和中部)以及北美地区。本文基于前人的研究成果, 结合新标本, 对中国伤齿龙类的系统分类、骨骼形态、骨组织、系统发育关系和古生物地理等方面进行了全面深入的评估与探讨。     

The perils of taxonomic inconsistency in quantitative palaeoecology: experiments with testate amoeba data

Payne, R. J., Lamentowicz, M. & Mitchell, E. A. D. 2010: The perils of taxonomic inconsistency in quantitative palaeoecology: experiments with testate amoeba data. Boreas, 10.1111/j.1502‐3885.2010.00174.x. ISSN 0300‐9483. A fundamental requirement of quantitative palaeoecology is consistent taxonomy between a modern training set and palaeoecological data. In this study we assess the possible consequences of violation of this requirement by simulating taxonomic errors in testate amoeba data. Combinations of easily confused taxa were selected, and data manipulated to reflect confusion of these taxa; transfer functions based on unmodified data were then applied to these modified data sets. Initially these experiments were carried out one error at a time using four modern training sets; subsequently, multiple errors were separately simulated both in four modern training sets and in four palaeoecological data sets. Some plausible taxonomic confusions caused major biases in reconstructed values. In the case of two palaeoecological data sets, a single consistent taxonomic error was capable of changing the pattern of environmental reconstruction beyond all recognition, totally removing any real palaeoenvironmental signal. The issue of taxonomic consistency is one that many researchers would rather ignore; our results show that the consequences of this may ultimately be severe.