内蒙古大兴安岭乌奴耳地区泥盆纪的两个牙形刺动物群

在大兴安岭乌奴耳地区发现两个牙形刺动物群。一个采自北矿组,牙形刺Caudicriodus angulatus cf.cauda指示北矿组的时代为Eifelian早期。另一个样品采自霍博山组(大民山组)上部的角砾岩层,产有牙形刺的混合动物群。Palmatolepis hassi,Pal.ljashenkovae,Pal.kireevae,Pal.subrecta,Polygnathus decorosus,Icriodus ex-pansus,I.symmetricus等牙形刺主要来自Frasnian晚期晚rhenana带。而Ancyrodella binodosa,Ancyrodella nodosa,Schimitognathus cf.hermanni则主要来自Gevitian期晚期和Frasnian期早期;Ancyrognathus ubiquitus是重要的事件种,见于linguiformis带至早triangularis带(F/F界线层);这个角砾岩层最后形成的时代可能是早triangularis带,含有多层位的再沉积的牙形刺。文中共描述了牙形刺11属22种,包括2个未定新种和1个未定种。     

渝东南地区泥盆纪牙形刺及其地层意义

本文研究了渝东南地区3个泥盆纪剖面的牙形刺,黔江濯水剖面的顶部(第7层)产有Palmatolepis quadrantinodosalobata等牙形刺,时代为法门期早期Middle crepida带至Lower rhomboidea带,是本区泥盆纪海相沉积的最高层位;酉阳兴隆剖面(第51层)发现牙形刺Palmatolepis semichatovae等牙形刺,时代为弗拉斯期晚期Lower rhenana带;濯水剖面的5层和6层、黔江水泥厂剖面的5层至7层以及酉阳兴隆剖面的52层和53层均产有较多的弗拉斯期晚期的牙形刺。本区写经寺组、黄家磴组和云台观组都可能是穿时的,写经寺组在各剖面残留厚度不同。写经寺组的时代为弗拉斯期晚期至法门期早期。本区缺少法门期中、晚期的典型的海相沉积。描述了一个新种Polygnathus chongqingensis Wang sp.nov.。     

广西荔浦晚泥盆世法门期竹节石

本文研究了广西荔浦上泥盆统榴江组上部扁豆状灰岩中所含的法门期竹节石2属3种,其产出层位分别为牙形刺化石带的 Palmatolepis crepida带和 Pa.marginifera带。     

湖南锡矿山剖面晚泥盆世底栖介形类及其大灭绝

研究的底栖介形类化石采自湖南锡矿山剖面晚泥盆世地层,共30属61种,含1新属,2未定属,13新种和20未定种。在晚泥盆世F/F生物集群灭绝事件之前和以后,根据底栖介形类的演化特征,分为正常期,包括3—5层;灭绝期,即6层;残存期,包括7,8,9a-c,11—13,15层;和复苏期,即20层以上地层。在湖南锡矿山上泥盆统剖面上,底栖介形类动物群遭受到F/F灭绝事件的重创,正常期的37种中仅11种在残存期中幸免于难,24种在本剖面上消失,灭绝种约占65%。对于F/F生物集群灭绝事件的发生机制,虽有多种解释,但造成底栖介形类灭绝的主要原因更可能是缺(贫)氧或含毒环境和气候变化。根据底栖介形类生态组合特征,正常期的介形类动物群代表近岸浅水开阔海台地环境;复苏期的介形类动物群可能代表半局限海台地环境。根据正常期、残存期和复苏期介形类动物群的组成特征,它们所生存的海底为正常的含氧环境。     

海南岛晚泥盆世—早石炭世牙形刺

作者描述了海南岛昌江县石碌地区昌江组首次发现的牙形刺Palmatolepis gracilis gracilis Bransonet Me-hl,P.gracilis sigmoidalis Ziegler,Polygnathus ansatus Ziegleret Klapper,Polynodosus germanus(UlrichetBassler),Neopolygnathus dentatus(Druce)等和白沙县金波地区南好组第二段的Siphonodella levis(Ni),Polygnathus cf. inornatus Branson等,共8属20种,并据此将含化石地层分别确定为晚泥盆世法门期和早石炭世杜内期早期。指出以往认为是中泥盆统吉维特阶带化石Polygnathus ansatus Ziegleret Klapper与法门期牙形刺化石共同出现于昌江组并非构造混杂所致,但并不排除可能是化石再沉积作用的原因。同意将Polynodosus属从Polygnathus属中分离出来,在我国首次采用Polynodosus。     

新疆东部托克逊马鞍桥剖面桑树园组刺毛-珊瑚礁的时代

新疆东部托克逊马鞍桥剖面桑树园组下部灰岩段的顶部发育了刺毛-珊瑚礁,通过对礁体及其上下地层的■类和牙形刺研究,可识别出■类3属14种,以属Eostaffella-Eostaffellina-Pseudostaffella组合为特征;牙形刺2属2种:Idiognathoides corrugatus和Idiognathodus sp.。■类Pseudostaffella antiqua,P.conspecta和P.paracompressa extensa的出现指示桑树园组灰岩段顶部相当于上石炭统滑石板阶上部,属于■类Pseudostaffella composite-P.paracompressa带。牙形刺Idiognathoides corrugatus和Idiognathodus sp.是晚石炭世巴什基尔期常见分子,对应上石炭统罗苏阶上部至滑石板阶上部。综合上述■类和牙形刺生物地层,可以确定桑树园组刺毛-珊瑚礁的时代为巴什基尔期中期(滑石板阶上部)。本文刺毛-珊瑚礁时代的确定可以为石炭纪中期生物灭绝/更替事件之后后生动物礁的复苏演化提供新认识。     

湖北宜昌黄花场下奥陶统弗洛阶Oepikodus evae带精细地层划分对比

全球中奥陶统及奥陶系第三个阶、大坪阶的界线层型剖面和点位(GSSP)确定后,文中作者对宜昌黄花场剖面弗洛阶上部Oepikodus evae带牙形刺生物地层序列进行再研究。通过对红花园组上部-大湾组下段一些关键层位中牙形刺样品的补充采集和牙形刺标本的系统检查,研究牙形刺属种垂向分布特征,修订一些牙形刺属种的首现层位。讨论Stolodus stola,Lundodus gladiatus,Oepikodus intermedius,Oepikodus communis,Trape-zognathus diprion,Baltonioduscf.B.triangularis等重要的多分子器官种分类问题。识别出Baltoniodus trian-gularis(Lindstr m)的先驱:Baltonioduscf.B.triangularis(Lindstr m)与Baltoniodus triangularis(Lindstr m)的区别。描述新建化石带属种,包括Baltoniodus triangularis(Lindstr m)。认为Oepikodus evae带上部时限范围内并未见Oepikodus evae分子,所以与国际地层指南(2000)关于间隔带和延限带的含义相悖。据此,厘定了原Oepikodus evae带的含义。并以牙形刺带分子首现为标志,将大湾组下段自下而上划分为3个间隔带,分别为:O.evae带,Trapezognathus diprion带和Baltonioduscf.B.triangularis带。其中Trapezognathus diprion带和Baltonioduscf.B.triangularis带为新建化石带。     

贵州独山泥盆纪弗拉期-法门期生物灭绝后的生物遗迹

黔南独山地区晚泥盆世弗拉期 法门期 (F/F)生物灭绝事件发生后 ,遗迹化石的出现早于其它化石。描述产于独山地区晚泥盆世法门期早期的遗迹化石 ,并分析其生态习性 ,它们在地层中的产出呈现出习性构造逐渐复杂、潜穴管逐渐“粗化”、由层面线性向二维空间到三维空间的发展 ,反映造迹生物有机体的逐渐变大和完善、生活和活动空间的不断扩大。     

下扬子区奥陶纪牙形刺多样性演变初探

根据前人和作者现有资料,对下扬子地区,特别是宁镇地区奥陶纪已经报道的牙形刺属种进行厘定,并按牙形刺带逐带进行多样性统计分析,初步编制出该地区奥陶纪牙形刺属种的地层延限表.研究表明;下扬子区牙形刺在奥陶纪的宏演化经历了3次较明显的辐射事件,分别发生在特马豆克期晚期-弗洛期早期(Serratognathus diversua带)、大坪期早期(Baltoniodus triangularis带)、达瑞威尔期晚期(Eoplacognathus suecicus带);此外,还经历了2次快速增长期,分别发生在达瑞威尔期早期(Lenodus antivariabilis带)、桑比期晚期至凯迪期早期(Hamarodus europaeus带),后者可能与局部环境变化有关.研究表明:华南海平面升降对下扬子区牙形刺宏演化趋势有重要影响.     

广西南宁大沙田下泥盆统那高岭组的牙形刺

世界泥盆系洛霍考夫阶和布拉格阶牙形刺生物地层有较明显的地理分区性,区域对比较困难,中国缺少连续的布拉格阶与洛霍考夫阶灰岩相剖面,牙形刺生物地层的研究,仍很不完善。广西南宁大沙田剖面是目前所知布拉格阶灰岩最多的剖面,在其下部发现了牙形刺Eognathodus irregularis,E.nagaolingensis,E.sulcatus mu morphs,Masaraella pandora(Murphy,Matti et Walliser,1981)W morphotype P element,其时代为布拉格期早期,大致相当于北美的Eognathodus irregularis-Gondwania profunda带和欧洲的E.sulcatus带。中布拉格期牙形刺Pseudogondwania kindlei带,还没有确立。晚布拉格期的牙形刺Polygnathus pirenniae带的存在和时限范围也没有在大沙田剖面得到确定。但大沙田剖面那高岭组的时代属布拉格期早期是肯定的。     

Revision of Famennian-Tournaisian (Late Devonian – Early Carboniferous) conodont biostratigraphy of Sardinia,Italy

Conodont biostratigraphy of the Famennian and Tournaisian of Sardinia is provided on the basis of all data available in the literature. More than 130 conodont taxa documented from this time-interval allow recognition of nineteen conodont biozones. The zonation scheme adopted here is broadly similar to the standard zonation schemes used in the Upper Devonian and Lower Carboniferous, though a few variations are needed to better accommodate the species occurrences in Sardinia: the velifer Zone and the styriacus Zone have been reintroduced, even though with slightly different meanings than previously used; the Lower praesulcata Zone is expanded to include the Middle praesulcata interval. The Upper praesulcata Zone and the sulcata Zone are missing. All zones are described and discussed and a complete list of bioevents is provided.     

新疆准噶尔盆地西北缘洪古勒楞组时代的新认识

标准地点的洪古勒楞组长期以来一直被认为是准噶尔盆地西北缘,乃至整个新疆北部以海相为主的层位上最高的晚泥盆世晚期的沉积。然而牙形类和微体脊椎动物的研究证实,该组跨弗拉阶－法门阶（Ｆ－Ｆ）界线,它至少包括了一小部分弗拉晚期和主体部分为法门早期的沉积。两个牙形类带ＬａｔｅｒｈｅｎａｎａＺｏｎｅ和ＭｉｄｄｌｅｃｒｅｐｉｄａＺｏｎｅ被识别出,它们在Ｆ－Ｆ界线附近,并分别在大绝灭事件（在ｌｉｎｇｕｉｆｏｒｍｉｓＺｏｎｅ内）之前后。另一个层位更高的牙形类带ＬａｔｅｃｒｅｐｉｄａＺｏｎｅ也可能存在。同时还证实,长期以来一直被认为“正常层序”的标准地点的洪古勒楞组的层序是倒转的。由此,含植物大化石Ｌｅｐｔｏｐｈｌｏｅｕｍｒｈｏｂｉｃｕｍ等的陆相层在下（此层可能归于该组下伏的朱鲁木特组）,而产牙形类和其它丰富的无脊椎动物的海相层在上。按牙形类年代带的年代地层时间表（Ｆｏｒｄｈａｍ,１９９２）,该组距今约３６８－３６４百万年。至于它和邻近地区和布克河组的关系,由于后者发现了更高层位的牙形类,两者还不能完全对比。     

Famennian conodonts from the Hongguleleng Formation at the Bulongguoer stratotype section,western Junggar,Northwest China

The Hongguleleng Formation, the highest and most important Devonian marine carbonate horizon in western Junggar, contains an endemic shallow-water Icriodus–Polygnathus conodont fauna with rare palmatolepids and other genera. The conodont faunas from the Bulongguoer and the Wulankeshun sections are similar, with high abundance (about 40%) of endemic taxa (13 taxa), indicating isolation of the Junggar Basin during early Famennian. Non-endemic species in the faunas suggest that the Lower Member of the Hongguleleng Formation is assignable to the Pa. rhomboidea Zone to the Pa. marginifera marginifera Zone of early Famennian, not including the Frasnian–Famennian boundary. The Upper Member may be of late Famennian–early Tournaisian in age on the basis of our preliminary faunal analysis.     

Sedimentary and biofacies records in calciturbidites at the Devonian-Carboniferous boundary in Moravia (Moravian-Silesian Zone, Middle Europe)

Summary At the Devonian/Carboniferous boundary, major climatic and oceanographic changes influenced sedimentation on carbonate platforms and in peri-platfrom asreas. Three deep-water carbonate successions in Moravia, which were selected to represent different paleotectonic settings, have been studied with the aim of testing the influence of eustatic, climatic and tectonic controls on sedimentation and conodont paleoecology and taphonomy. On the slopes of the wide carbonate platforms of the Moravian Karst Development (Lesní lom and Grygov sections), an exemplary highstand shedding systems developed in the upper Famennian (expansa Zone), marked by a pronounced thickness of their respective calciturbidite successions and an abundance of shallow-water skeletal grains.Palamatolepis— andBispathodus-dominated conodont assemblages contain an admixture ofPolygnathus representing a transported, near-shore component. The eustatic sea-level fall in the praesulcata Zone and the lowstand conditions at the D/C boundary resulted in a decline of carbonate platform production and condensed deposition or nondeposition. In the Lesní lom section, a condensed sequence of turrbiditic calcarenites and shales (Middle praesulcata—lowermost sulcata Zone) was followed by lime mud calciturbidites (sulcata and duplicata Zones). In the conodont assemblages, the first event in the Lower praesulcata Zone was associated with the reduction of ‘mesopelagic’Palmatopic and a bloom of epipelagicPolygnathus communis. The second event in the Middle praesulcata Zone corresponds to the onset of polygnathidprotogranthodid biofacies, indicating a carbonate slope environment. In the Grygov section, a pronounced thickening and upward-coarsening succession of tubiditic calcilutites through calcarenites and intraclast breccias, with poor palmatolepid-bispathodid connodont assemblages (expansa Zone), indicates a progradation of the calciturbidite system associated with sea-level highstand. After a break in sedimentation, covering the interval from the Lower praseulcata to the base of Lower crenulata Zone, thick-bedded, fine-grained calciturbidites were deposited in the Lower crenulata Zone, and are associated with poor, mixed assemblages where siphonodellids and polygnathids predominate. At the isosticha-Upper crenulata/Lower typicus boundary, coasre grained, turbiditic calcarenites and breccias rich in clastic quartz grains and mixed conodont assemblages with reworked Frasnian and Famennian conodonts indicate a deep erosion of the source area, presumably due totectonic uplift (relative lowstand). In the Jesenec section, on the flanks of the volcanic seamount (the Drahany Development), a deep-water Upper Famennian condensed succession of calciturbidites and presumably winnowed pelagic limestones is marked by conodont assemblages of palmatolepid-bispathodid biofacies. More proximal calciturbidites with mixed deep-water and shallowwater conodonts prograde at the top of the Upper Famennian succession (Middle to Upper expansa Zone). A striking hiatus, covering the interval from the Early preaesulcata to the base of Lower crenulata Zone, resulted from extreme condensation and submarine bottom current erosion due to sea-level lowstand in the late Famennian and early Tournaisian. The renewed middle Tournaisian calciturbidite sedimentation with strong evidence of erosion at the source area indicates global eustatic rise and tectonic uplift of the Drahany Development seamounts (relative lowstand). The earlier occurrence of the uplift in the Jesenec area, relative to the Grygov section, shows the advance of tectonic processes over time in the Moravian-Silesian basin (orogenic polarity) as a consequence of Variscan orogenic movements.     

湖北宜昌黄花场剖面中/下奥陶统界线附近的牙形剌

重点描述宜昌黄花场剖面中 /下奥陶统界线附近的重要牙形剌共 3属、5种和 2新种Bergstroe mognathussp .nov .,BaltoniodustetrachotomusLiandWangsp .nov .,并对Oepikodusevae带和Baltoniodustriangu laris带分子的首现位置及带的含义进行厘定。作者还在此剖面大湾组下段发现北美中大陆区暖水型牙形剌Tripoduslaevis和Protoprioniodusaranda ,并确定Tripoduslaevis的首现位置在Baltoniodustriangularis带底界之上 0 .3m处。Tripoduslaevis的首次出现曾提议为中奥陶统的底界的标志 (见陈旭等 ,2 0 0 0 ) ,在宜昌黄花场剖面上Tripoduslaevis的首现位置接近Baltoniodustriangularis带底界 ,对确定中 /下奥陶统界线很重要。由于在黄花场剖面可识别出Baltonioduscrassulus—B .gladiatus—B .triangularis演化谱系 ,作者建议以B .triangularis的首次出现作为中奥陶统的底界 ,宜昌黄花场剖面为中 /下奥陶统界线的层型剖面。同时 ,文中将本区的牙形刺带与世界其它地区作了对比。     

The hydrodynamics of conodont elements

Accurate palacobiological interpretation of the fossil record requires an assessment of biostratinomic processes. Samples which have undergone significant post-mortem sorting reflect only the hydrodynamic regime prevalent at the time of deposition and not the original faunal composition. Conodont bedding plane assemblagcs are rare and many conodont taxa are known only through reconstructions of apparatuses using empirical techniques. These methods require large collections where the elements have undergone no significant post-mortem transportation. In this paper measurements of settling velocities are used to predict relative hydrodynamic behaviour in a current. The settling velocity of a particle is of about the same magnitude as the current required to entrain that particle. Conodont elements rotate during fall, spinning about a central axis. Elements with equal Reynolds numbers may have different drag coefficients indicating that shape is an important factor in determining conodont element hydrodynamics. In a current of increasing velocity the predicted order of entrainment of elements of the same equivalent size is as follows: Polygnathus S. Ancyrodella Pa. Polygnathus Pa. Palmatolepis Pa. Polygnathus Pb. lcriodus Pa. Conodont elements grow by accretion of lamellae; to the first approximation. length is a satisfactory indication of size. Length can therefore be used to predict the settling velocities of elements, and which elements will sort together. Measurement of element lengths allows a rapid estimation of the degree of post-mortem sorting undergone by a sample and therefore its suitability for use in palaeobiological analysis. □ Conodont hydrodynamics, biostratinomy, drag coefficient, settling velocity. sorting.     

Patterns of bilateral asymmetry and allometry in Late Devonian Polygnathus conodonts

Conodont animals were early jawless vertebrates equipped with a feeding apparatus composed of several tooth‐like elements. The P1 elements, at the rear of the apparatus, were characterized by a robust shape and rapid morphological evolution. Occlusion occurred between paired right and left P1 elements, occasioning some bilateral asymmetry, which, together with allometric growth, may partially obliterate the temporal differences. The present study aims to disentangle these different components of morphological variation in Late Devonian Polygnathus P1 conodont elements. An extensive 2D geometric morphometric analysis of the platform shape was performed through the Famennian record of two outcrops. This analysis was completed by a 3D study on a subset of conodont elements. The 2D and 3D morphometric quantifications provided highly congruent results, showing that the 2D shape constitutes a good approximation of the element geometry. The 3D analysis delivered further insights into the relationship between the geometry of the elements and the constraints related to occlusion. The 2D analysis allowed a quantitative assessment of the variation among species and through time. Allometry and bilateral asymmetry were differently expressed depending on the species considered, suggesting that constraints imposed on pairing by the morphology of the elements varied even among related species. The within‐species variation was so important that it largely obliterated temporal trends; a relationship of Polygnathus shape and conodont biofacies variations through the Famennian nevertheless suggested an evolution driven by ecological interactions between conodont genera.     

New Middle Devonian conodont data from the Dong Van area,NE Vietnam (South China Terrane)

Middle Devonian conodonts from the Si Phai section in NE Vietnam are described. The section ranges from the Middle Devonian ensensis to timorensis conodont zones to the Late Devonian rhomboidea conodont Zone. A rich overall assemblage is described, including 27 taxa of species or subspecies rank and 11 taxa described in an open nomenclature. Among the dominant Polygnathus forms, four new taxa are described: Polygnathus linguiformis saharicus subsp. nov., Polygnathus linguiformis vietnamicus subsp. nov., Polygnathus rhenanus siphai subsp. nov., and Polygnathus xylus bacbo subsp. nov. Conodont assemblages are attributed to polygnathid, polygnathid-klapperinid, and klapperinid conodont biofacies representing hemipelagic to pelagic environments. The klapperinid biofacies, unreported in the previous literature, are here attributed to offshore areas of the external shelf. The taxonomic compositions of the studied conodont assemblages, as well as their CAI characteristics (CAI 4–5), suggest a palaeogeographic affinity of the studied strata to the Chinese Devonian Guangxi Basin, and the South China Terrane in general. Furthermore, the conodont biofacies and the palaeogeographic distribution of the fauna are discussed.     

Horizon of the oldest known bryozoans (Ordovician)

Among the six species of fossil bryozoans described by Xia et al. [Xia, F.S., Zhang, S.G., Wang, Z.Z., 2007. The oldest bryozoans: new evidence from the late Tremadocian (Early Ordovician) of East Yangtze Gorges. Journal of Paleontology 81 (6), 1308–1326] from the Fenghsiang Formation of the Chenjiahe section of Yichang and the Guanzhuangping section, Liujiachang Town of Songzi, the Yangtze Gorges, Nekhorosheviella nodulifera occurs in the pristinus Conodont Subzone (lower Subzone of deltifer Conodont Zone) and the five other species are associated with the conodont Paltodus deltifer deltifer and the graptolites Acanthograptus sinensis and A. erectoramus. Based on the conodonts and graptolites, this bryofauna stratigraphically corresponds to the A. sinensis Graptolite Zone or P. deltifer Conodont Zone. The bryofauna is of Tremadocian Age (Early Ordovician) and represents the oldest bryozoans so far as known.