华东志留纪最早期的华夏正形贝动物群及其宏演化意义

志留纪最早期的腕足动物群在文献中很少记录,与标准笔石相伴者更为稀罕。江西玉山志留系底部因发现Akidograptus ascensus带的笔石而确定该处盛产志留纪初期（鲁丹早期）、多样性较高的腕足动物群。根据组成、性质与层位,它与浙江江山、常山、淳安、余杭等7个地点的同期组合可统一命名为华夏正形贝动物群（Cathaysiorthis Fauna）。它包含了不同群集,都产自细碎屑岩（如泥岩）中,其分布主要受海水深度和距华夏古陆远近的控制。这个动物群生长在奥陶纪大灭绝后的残存期,文章探讨了它的残存特征。研究揭示,奥陶纪末大灭绝对腕足动物演化的一个实质性的贡献在于制约了奥陶纪占优势的A组（正形贝／扭月贝大类群：发育铰合面、窗齿型铰齿、正扭型主突起和简单腕器官）的繁盛态势,滋生了B组（五房贝／无洞贝大类群：发育后转面、弓齿型铰齿和复杂腕器官但缺失正扭型主突起）在志留纪的优势,造成腕足动物宏演化历程中的一次重大转折。文中提出“优势替代滞后型式（Pattern of lag of dominance replacement）”,专指A组类群的优势被B组类群替代的时间不是紧跟在奥陶纪末大灭绝之后,而是距大灭绝结束约4Ma之后。文中描记新属华夏正形贝（Cathaysiorthis gen．nov．）。     

吉中地区晚古生代腕足动物古生物地理与环境的协同演化*

吉中地区发育了普里道利期—洛霍考夫期Retziella、杜内期通气沟组以及空谷期—沃德期哲斯等腕足动物群。前两者属于"暖水"动物群、后者属于"凉水"动物群。同时参考珊瑚和等动物群分析,说明吉中地区从普里道利期至阿瑟尔期发育"暖水"动物群,从空谷期到沃德期发育"凉水"动物群。"凉、暖"转换是以寿山沟组的Monodiexodina动物群为代表,发生在萨克马尔期。"凉、暖"水动物群的发育及其转换是构造古地理与气候变化双重因素导致的结果。晚志留世—早泥盆世,西伯利亚板块、哈萨克斯坦板块、佳-蒙地块均位于中—低纬度带。吉中地区晚志留世—早泥盆世(乃至中泥盆世)腕足动物群属于"暖水"动物群,古生物地理区划属于中-澳生物地理区。石炭纪,东欧板块东北缘、哈萨克斯坦板块大部分地区、佳-蒙地块南缘属于特提斯洋北缘构造域,发育了特提斯洋北缘腕足动物群,形成了特提斯北缘生物地理区,吉中地区腕足动物群属于这一生物地理区。空谷期—沃德期凉水型哲斯腕足动物群的形成是由于佳-蒙地块西端与塔里木板块以及华北板块西端拼合,形成了西拉木伦洋构造域,以及此时期全球降温事件导致的结果。古生物地理、构造古地理以及古气候之间的协同演化关系表明吉中地区晚古生代地层应属于佳-蒙地块南缘的大陆边缘沉积。     

江苏仑山地区上奥陶统五峰组放射虫动物群及其地质意义

五峰组以盛产笔石动物群著称,时代为凯迪晚期(相当于英国的阿什极尔期),其中也发现了放射虫.该时期的放射虫在全球并不多见.本文首次描述江苏句容仑山地区五峰组的放射虫动物群,该动物群以不具刺的球形放射虫最为发育,并出现少量Inaniguttidae科的分子,化石保存较差,属种单调,分异度很低,这些特点与大西洋沿岸地区陆表海...     

新疆库鲁克塔格上奥陶统杂土坡组叶月贝动物群的发现*

叶月贝腕足动物群是晚奥陶世海洋较深水底域中一个重要的底栖壳相动物群。文中首次报道了在新疆东南部库鲁克塔格地区却尔却克山上奥陶统杂土坡组发现的叶月贝动物群,包括腕足动物5属5种(含两个未定种),分别为:Apatobolus cf.plicatus,Lingulellasp.,Foliomena xinjiangensis,Kassinella(Kassinella)cf.tchingisensis和Eoplectodonta sp.。壳相化石与笔石共同产出,保存在深灰色泥岩中,推测大致相当于BA5甚至稍深的底域环境。在同一条剖面上,叶月贝动物群曾报道于层位稍高的银屏山组[上奥陶统凯迪阶(Katian)上部],二者之间可能存在分类学和古生态学的联系。叶月贝腕足动物群在塔里木板块的持续发育为深入开展这一古板块的古地理重建提供了依据。     

古植物整体研究和重建

唐山地区奥陶纪树形笔石早有报道(孙云铸,1935),但本文记述的,在本区西域山长山组中部所发现的寒武纪笔石尚属首次。这是一个古老的,以固着底栖为生的原始树形笔石动物群,包括了Dictyonema, Airograptus和Dendrograptus 3属、6种(其中1新种)。证明了Airograptus属的地质历程最早可追溯到中长山期。也揭示了本区繁荣的奥陶纪树形笔石群从上寒武统的属种演化过渡而来的。     

新疆塔里木柯坪地区上奥陶统凯迪阶串管海绵类化石及其滤食选择性探讨北大核心

奥陶纪是串管海绵早期演化的一个关键阶段,记录了该类群的首次大规模辐射演化事件(属级分类单元达15个)。然而,现有大部分奥陶系串管海绵的报道来自澳大利亚东部和北美等地,在中国至今仅发现了两个属,与前述地区相比研究程度偏低。早期研究主要基于形态学特征对串管海绵进行系统分类描述,对其滤食策略知之甚少,因此制约了对此类海绵在奥陶纪底栖生态系统作用的相关探讨。本文系新疆塔里木柯坪地区奥陶纪串管海绵的首次系统古生物学报道,详细描述凯迪阶(上奥陶统)印干组中保存完好的阔室丛花海绵(Corymbospongia amplia)化石的形态学特征,并通过研究标本外壁微孔孔径的大小分布,探讨其滤食选择性。海绵外壁微孔孔径的分析表明:小型和微型浮游生物可能是其食物的主要来源,而多细胞浮游动物因个体尺寸大于海绵外壁微孔,不能被阔室丛花海绵捕获。本研究为奥陶纪串管海绵古生态学及其地球生物学意义的探讨提供了进一步的依据。     

中国宜昌王家湾晚奥陶世五峰组几丁虫的初步研究

中国宜昌王家湾北剖面已被提名为奥陶系赫南特阶的全球候选层型剖面。为此著者分析了王家湾地区,特别是王家湾南和王家湾小河边奥陶—志留系间相关地层共20个层位的几丁虫样品。初步研究的结果表明,王家湾赫南特阶之下,相当奥陶纪第6个阶顶部,即五峰组中部产出的几丁虫与美国内华达中部Vnini河谷以及加拿大极区Cape Mannig的Ordochitina nevadensis 和Nevadachitina vininica 几丁虫带的分子可以进行对比。     

准噶尔盆地北缘中中新世啮齿类

本文记述了新疆准噶尔盆地北缘,乌伦古河沿岸哈拉玛盖组中中新世动物群中的啮齿类,共三属四种.其中, Sinomylagaulus halamagaiensis gen. et sp. nov., Atlantoxerus junggarensis sp. nov. 和 A. giganteus sp. nov. 分别是 Mylagaulidae (圆齿鼠科)和 Atlantoxerus (阿特拉地松鼠)在我国的首次记录. Amblycastor tungurensis 的存在表明该动物群的时代大致为通古尔期,与欧洲陆生哺乳动物分期 MN 7-8 (Astaracian) 相当.     

奥陶-志留系界线地层生物带的全球对比

详述扬子区晚奥陶世晚期(阿什极期)至兰多维列世初期的生物带序列,修正部分的笔石带,与全球各重要地区进行对比.研究表明,全球奥陶系顶部赫南特亚阶及其上下地层在我国的扬子区发育最好,地层连续发育并广泛出露,生物带发育齐全,不但有连续的笔石带,而且有世界广布的赫南特贝腕足动物群,有望在我国建立赫南特亚阶的全球层型剖面和点(GSSP).     

华南与缅甸奥陶纪末赫南特贝动物群中的无铰类腕足动物

在奥陶纪末生物大灭绝的两幕之间,海洋底域繁盛着赫南特贝腕足动物群（Hirnantia Fauna）。它数量丰富,分布广泛,历程短暂。以往国内外学者研究这个动物群时,常把有铰类腕足动物作为重点,而无铰类只被简单描述或列出名单,整体面貌不明。无铰类化石尽管材料有限、研究基础薄弱,但只就属的数目而言,占据了全球赫南特贝动物群总属数的近1/5,其群落、演化和环境意义不可小觑。文中专门记述上扬子区（华南古板块）观音桥层（赫南特早中期）与缅甸曼德勒地区（滇缅马苏古地体）Hwe Mawng紫色页岩段（赫南特中期）所产赫南特贝动物群的无铰类化石,计有3目、4超科[Linguloidea（舌形贝超科）、Discinoidea（平圆贝超科）、Craniopsoidea（似髑髅贝超科）和Cranioidea（髑髅贝超科）]的10属、12种,包括5个命名属种[Plectoglossa cf. davidsoni (Barrande),Schizotretinia cf. euxina (Havlí?ek), Pseudopholidops partibilis (Rong),Petrocrania cribrum (Temple),Xenocrania haimei (Reed)]和7个未定种（Trematis sp.,Paracraniops sp.,Acanthocrania sp.,Petrocrania? sp. 1,Petrocrania? sp. 2, Pseudolingula? sp. 和Orbiculoidea sp.）,其中,Pseudolingula? sp.和Orbiculoidea sp.两个未定名种因标本不佳,未正式描述。其中,以Pseudopholidops最为常见,其次是Xenocrania和Petrocrania。前两属是华南、滇缅马苏、波罗的卡、阿瓦隆尼亚、佩鲁尼卡等古板块或地体赫南特贝动物群的常见分子。它们已知限于南、北纬30°之间的低纬度地区,这可能与化石采集和研究程度有关,但更可能反映奥陶纪末全球气候仍存在分异现象。研究识别了奥陶纪晚期无铰类腕足动物7个目,可归为3个类群：灭绝目（仅神父贝目Paterinida）、消减目（多样性与丰度大幅衰减,尤其是三分贝目Trimerellida和乳孔贝目Acrotretida在Hirnantian销声匿迹）和延续目（适应能力强、忍耐阈值高,成功穿越大灾难的首幕）。这些分类单元对研究奥陶纪-志留纪交界期腕足动物群的多样性、群落生态、生物地理及宏演化等有重要意义。     

贵州思南奥陶纪末至志留纪初大息场组的笔石

贵州思南奥陶纪末至志留纪初大息场组的笔石研究结果表明,大息场组共产出笔石6属7种:Styracograptus chiai(Mu,1949),Normalograptus mirnyensis(Obut and Sobolevskaya,1967),Normalograptus ajjeri(Legrand,1977),Metaclimacograptus hughesi(Nicholson,1869),Avitograptus avitus(Davies,1929),Atavograptus atavus(Jones,1909)和Korenograptus laciniosus(Churkin and Carter,1970)。自下而上可识别出相当Dicellograptus complexus带、Akidograptus ascensus带和Cystograptus vesiculosus-Coronograptus cyphus带的3个含笔石地层带。虽然大息场组的笔石动物群分异度较低,但全都是上扬子区奥陶-志留系之交的常见属种,除S.chiai(Mu)之外,其它都是全球广布的物种。     

A relict Ordovician brachiopod fauna from the Parakidograptus acuminatus Biozone (lower Silurian) of the English Lake District

At Yewdale Beck in northern England, a brachiopod fauna dominated by species of Hindella, Kinnella, Mirorthis, Paromalomena and Plectothyrella , occurs interbedded with a graptolite fauna which includes Akidograptus ascensus , Atavograptus ceryx , Persculptograptus parvulus and Normalograptus spp. (including probable examples of N. normalis , N. angustus and N. medius ) within the lower part of the Skelgill Formation. This suggests that taxa of the terminal Ordovician Hirnantia fauna occur within the lower P. acuminatus Biozone, representing the youngest documented occurrence of the Hirnantia brachiopod fauna. Biostratigraphy, brachiopods, graptolites, Ordovician-Silurian boundary.     

The latest Ordovician Hirnantia Fauna (Brachiopoda) in time and space

The diachronous temporal and spatial distribution of the Hirnantia brachiopod fauna and the complicated pattern of terminal Ordovician events are documented through biostratigraphical analysis of the Ordovician-Silurian boundary strata in S China, Sibumasu, Xizang and elsewhere. The duration of these events (longer than the half Myr derived from isotopic excursions) indicates that they were not abrupt and instantaneous. The presence of some core taxa of the Hirnantia fauna in the upper P. pacificus Biozone (known from their earliest occurrence in China) signals the start of increased water ventilation due to the invasion of cool water across the Yangtze Basin. Low- and higher-diversity Hirnantia faunas related to onshore, shallow-water and to offshore, deeper-water environments, respectively, developed first in the basal and upper N. extraordinarius-N. ojsuensis Biozone. Disappearance of most of the fauna in the early N. persculptus Biozone suggests that the glacial maximum started to decline. The presence of the Hirnantia fauna in the upper N. persculptus to the lower P. acuminatus biozones indicates the continuation of cool water environments in some places. The diachronous disappearance of deteriorating environments (earlier in later Hirnantian and finally in the early Rhuddanian) is associated with geographical heterogeneity. Occurrences of atrypids, pentamerids and spiriferids along with key elements of the Hirnantia fauna in N Guizhou provide a link between the Late Ordovician radiation and Early Silurian recovery of these major brachiopod groups.     

湖南益阳早、中奥陶世的叶笔石属(Phyllograptus)

报道湖南益阳早、中奥陶世的叶笔石1属5种,包括Phyllograptus anna Hall,1865,Phyllograptus anna longus Ruedemann,1947,Phyllograptus anna ultimus Ruedemann,1904,Phyllograptus claviger Monsen,1937,Phyllograptus claviger acuminatus(Chen and Xia),1979。研究表明,该属主要产出于弗洛晚期至大坪中期,在早、中奥陶世笔石多样性演变事件第一阶段的后期(Corymbograptus deflexus带),叶笔石所代表的上攀伸展类型就已萌芽,且在第二阶段(Pseudophyllograptus angustifolius elongatus带-Isograptus victoriae divergens带)于均分笔石动物群中占据优势地位,对该动物群内部类群的演替起着承前启后的作用,同时也验证了笔石动物群自身的演替对于其多样性演变具有重要影响。     

The oldest known occurrence of the Foliomena fauna in the uppermost Darriwilian (Middle Ordovician) of South China

The oldest Foliomena fauna was, until now, known from the middle–upper Miaopo Formation (Nemagraptus gracilis Biozone, lower Sandbian, basal Upper Ordovician) of South China. In this study, the oldest record of the fauna is set back to the latest Darriwilian (upper Hustedograptus teretiusculus Biozone), represented by Foliomena jielingensis and some typical constituents of the Foliomena fauna from the basal Miaopo Formation at Jieling, northern Yichang, western Hubei Province, central China. The Miaopo Formation is characterized by its organic‐rich dark‐grey shale facies, unique in its localized distribution on the Yangtze Platform, and distinguished by its rich and diverse benthic and graptolitic faunas. This suggests an origin of the Foliomena fauna in periodically oxygen‐starved local depressions on the Yangtze Platform during the Middle–Late Ordovician transition.     

川西汉源-荥经地区下奥陶统大乘寺组的笔石

对川西汉源-荥经地区CYD2井下奥陶统弗洛阶大乘寺组的笔石进行研究,结果表明Baltograptus deflexus笔石带在这一覆盖区发育良好。CYD2井的该带笔石动物群共含2属5种。根据下垂对笔石类的始端发育型式,修正前人对波罗的笔石属(Baltograptus)和巅峰笔石属(Corymbograptus)内一些种的归属,并对CYD2井的5种笔石进行描述。可能受制于钻心标本的限制,该地区的Baltograptus deflexus带笔石动物群分异度较低。川西汉源-荥经-峨眉山地区的大乘寺组与上覆二叠系梁山组呈假整合接触,表明该地区长期遭受沉积间断和剥蚀作用,B.deflexus带的确定,指示了这一长期剥蚀作用的最大深度。     

BRYOZOAN MUD-MOUNDS FROM THE UPPER ORDOVICIAN JIFARAH (DJEFFARA) FORMATION OF TRIPOLITANIA, NORTH-WEST LIBYA

Abstract:  A bryozoan fauna from carbonate mud-mounds is described from subsurface well cores from the Upper Ordovician (Lower Ashgill) Jifarah (Djeffara) Formation of Tripolitania, north-west Libya. Among a diverse assemblage dominated by trepostomes, nine species of bryozoans are identified, including Jifarahpora libyensis gen. et sp. nov. Delicate and robust branching, encrusting and nodular bryozoan growth forms are all common. The bryozoan-rich limestones are mostly mudstones and wackestones, with bafflestone and floatstone textures, but the mounds apparently lack organic framework and microbial fabrics. Regional geophysical data indicate rapid thickness changes between wells, where mound complexes locally up to 100 m thick had limited topographic relief over the surrounding sea floor. The mounds formed in a high-latitude, cool-water carbonate belt that extended widely across the northern margin of Gondwana. Quaternary analogues from the Great Australian Bight suggest that these early Ashgill mounds may have developed in slope environments during an episode of glacial lowstand that preceded the late Ashgill, Hirnantian glacial event.     

扬子区中、晚奥陶世和兰多维利世四射珊瑚起源、扩散及生物古地理关系

扬子区中奥陶世—志留纪兰多维利世四射珊瑚产出丰富 ,尤以兰多维利世最为繁盛。目前已报道的1 2 3属 (包括中奥陶世 4属 ,晚奥陶世 2 5属 ,兰多维利世 94属 )中 ,有 30属最早出现在扬子区 ,尔后扩散到欧洲、北美和其它邻区。例如 :Calostylis最早出现在川南的中奥陶世 (Llandeilo)地层中 ;Aphyllum和Cantrillia最早出现在浙西的晚奥陶世中Ashgill地层 ;扭心珊瑚类Briantelasma ,Pycnactis和Tunguselasma等 ,最早出现在黔东北晚Ruddanian地层 ;柱珊瑚类Ceriaster、Stauria、Amplexoides、Synamplexoides等 ,泡沫珊湖类Maikottia ,Rhizophyl lum等均最早出现在黔东北的中兰多维利统 (MiddleLlandovery)。根据这些资料 ,我们认为扬子区应该是奥陶纪和志留纪四射珊瑚起源中心之一。文中论述扬子区中奥陶世—兰多维利世四射珊瑚动物群特征及其生物古地理关系。该区中奥陶世珊瑚以穿孔珊瑚类的Calostylis和Yohophyllum为特征。下扬子区浙西晚奥陶世三衢山组 (中Ashgill)四射珊瑚群有某些澳大利亚分子Hillophyllum和Bowanophyllum ;而上扬子区晚Ashgill观音桥层的四射珊瑚动物群与北欧同期珊瑚群有高度的相似性。这表明扬子区当时与欧洲具有较密切的古生物地理关系。扬子区兰多维利世四射珊瑚群与西伯利亚。     

HIRNANTIAN (LATEST ORDOVICIAN) GRAPTOLITES FROM THE UPPER YANGTZE REGION, CHINA

Abstract:  The Upper Yangtze region yields a Hirnantian (latest Ordovician) graptolite fauna that includes 41 species assigned to 13 genera. This fauna is particularly important for understanding the Late Ordovician mass extinction event because it is the most diverse known from this interval. In addition, it records the survival, well into the Hirnantian, of many taxa of the Dicranograptidae-Diplograptidae-Orthograptidae (DDO) fauna, which was previously regarded as having gone extinct at the beginning of the Hirnantian. Taxa exhibiting six different astogenetic patterns, including taxa with reclined stipes, scandent, biserial, full-periderm and 'archiretiolitid' rhabdosome forms occur in the lower Normalograptus extraordinarius-N. ojsuensis Biozone. In contrast, in the upper N. persculptus Biozone only four genera remain, all but one of which are Normalograptidae: scandent and biserial taxa with Pattern H astogeny. Normalograptids are the dominant form of the succeeding, lower Rhuddanian, faunas. The Yangtze faunas also document the early expansion of normalograptids coeval with the decline of the DDO fauna. Many previously identified species considered endemic to China have been synonymized; 24 of the 41 species recorded here have been recognized elsewhere. No new taxa are described.