Chitinozoan zonation of the Late Ordovician and the Early Silurian of the island of Anticosti, Québec, Canada

A reappraisal of chitinozoan distribution across the Ordovician-Silurian boundary on the Island of Anticosti has led to the recognition of a new zone, the Ancyrochitina ellisbayensis biozone, in the uppermost part of the Ellis Bay Formation. This biozone lies between the well defined Upper Ordovician Spinachitina taugourdeaui biozone and the lowest Silurian (Rhuddanian) Plectochitina nodifera biozone of the Becscie Formation. The occurrence of such diagnostic species as P. nodifera, Belonechitina postrobusta, Conochitina electa and Ancyrochitina ramosaspina in the Lower Silurian of Anticosti points to a close similarity to faunas in Estonia and north Latvia and indicates an age ranging from the Parakidograptus acuminatus to the Coronograptus cyphus in terms of graptolite zones. The chitinozoan biozonation harmonizes with that based on conodonts and, to a lesser extent, with the known graptolite faunal succession. Five new species: Ancyrochitina ellisbayensis sp. nov., Clathrochitina postconcinna sp. nov., Conochitina gunriveris sp. nov., Clathrochitina perexilis sp. nov., Bursachitina basiconcava sp. nov. and three species in open nomenclature are described.     

EARLY LLANDOVERY CHITINOZOANS FROM JORDAN

Abstract:  Chitinozoans recovered from cores BG-14 and WS-6 in southern and eastern Jordan are described. Sample ages are well-constrained by graptolite data to the ascensus-acuminatus and vesiculosus graptolite biozones. Eighteen chitinozoan taxa are recognized, with Spinachitina  fragilis , Plectochitina  nodifera , Ancyrochitina  laevaensis and Belonechitina  postrobusta allowing correlation with both local and global chitinozoan and graptolite biozonations for the Rhuddanian. One new species of chitinozoan is erected, Belonechitina  pseudarabiensis sp. nov.     

重庆城口大塘口下奥陶统红花园组和湄潭组下部的几丁虫

文中图示和描述了重庆城口大塘口奥陶系红花园组和湄潭组下部营盘段的几丁虫计 6属, 17种。其中包括 7个未定种和 3个新种 (Conochitinadatangkouensissp. nov., C. wengxigouensissp. nov., Rhabdochitinachenk ouensesp. nov. )。讨论了几丁虫的地理和地层分布特点及其与笔石生物带的关系,阐明了红花园组和湄潭组下部营盘段不同笔石带(A. filiformis, D. bifidus和A. suecicus笔石带)中几丁虫的组合特征,并与国外同期地层几丁虫组合进行了对比。     

上扬子区奥陶系Nemagraptus gracilis 笔石带的几丁虫

作者系统描述了在重庆城口廖子口和宜昌分乡普溪河奥陶系庙坡组Nemagraptusgracilis笔石带中发现的几丁虫化石,共7属9种。由于此前对该层位的几丁虫研究较少,因此本次所发现的几丁虫化石具有重要的生物地层意义。     

新疆塔里木盆地奥陶纪冷水型胞石

文内描述了在新疆塔里木盆地覆盖区QB-1井(黑土凹线)和TZ-32井(却尔却克组)中发现的3种奥陶纪冷水型胞石.即Tanuchitina sp.cf.achabae Paris,Linochitina pissotensis Paris和Siphonochitina bella sp.nov.,时代为中到晚奥陶世。冷水型胞石在奥陶纪主要分布于冈瓦纳大陆北缘和英国等中高纬度地区,沿冈瓦纳大陆边缘向北的洋流将这些中高纬度的表层冷水型胞石带入低纬度的塔里木板块内,热带下沉作用能使它们在深水的盆地相中获得适宜的环境温度而得以生存。     

陕西梁山地区宝塔组介形类

本文报道了陕西省南郑县梁山地区中奥陶统宝塔组介形类8属10种,其中包括3新属8新种。这些介形类化石的发现,为该时代地层的划分、对比增添了新的古生物依据。     

Cryptostomid Bryozoans From The Sassito Formation,Upper Ordovician Cool‐Water Carbonates of the Argentinean Precordillera

Abstract: Two new bryozoan species are described from the Upper Ordovician Sassito Formation of the Argentinean Precordillera: Moyerella  spinata sp. nov. and Phylloporina  sassitoensis sp. nov. The bryozoans are found in cool‐water carbonates. The Silurian genus Moyerella is reported the first time in the Ordovician, showing palaeobiogeographic connections with Estonia and Siberia.     

Middle–Late Ordovician chitinozoans from Songliang of Qiaojia,western South China,and their biostratigraphic implications

Ordovician chitinozoans are as yet inadequately documented from the western Yangtze Platform, South China. Here we present a systematic study on chitinozoans from a Middle–Upper Ordovician succession at Songliang of Qiaojia, northestern Yunnan, southwestern China. Altogether 34 species of 12 genera are identified from the upper Hungshihyen and the Huadan formations. The top of the Hungshihyen Formation yields typical Early and Middle Ordovician forms, for instance, Lagenochitina obeligis and Belonechitina chenjiawuensis, with the latter only known from the lower Darriwilian in South China, thus suggesting an early Darriwilian age for this interval. The chitinozoans recovered from the Huadan Formation include Lagenochitina prussica and Spinachitina fossensis, both are mainly confined in Katian and sometimes ranging into younger strata. This indicates an age younger than the middle to late Darriwilian previously determined for the Huadan Formation. However, conflicts exist in age assignment of the Huadan Formation based on chitinozoan and other evidence, and further work is required.     

ORDOVICIAN NAUTILOID FAUNA FROM LUNSHAN, JURONG, JIANGSU

The fossil nautiloids described in this paper were collected in 1984 and 1985 from Lunshan, Jurong in Jiangsu; there the Ordovician strata are well developed and may be divided in descending order into seven formations as follows:Upper Ordovician: Wufeng Formation Tangtou FormationMiddle Ordovician Pagoda Formation Lower OrdovicianKuniutan FormationDawan FormationHunghuayuan FormationLunshan FormationThese nautiloids comprise 36 species belonging to 13 genera (including one new genus and 11 new species), namely,Middle OrdovicianPagoda FormationSinoceras chinense (Foord), Michelinoceras changjiangense Chen, densn (Y), M. paraelongatum Chang.Lower OrdovicianKuniutan FormationRhynchorthoceras jurongense sp. nov., R. lunshanense sp. nov., Dideroceras wahlenbergi (Foord), D. holmi Flower, Michlinoceras irregulare sp. nov., Kotoceras gaoluncunense sp. nov.Dawan Formation.Cochlioceras yantzeense Chang, Chisiloceras ichangense Wang, C. yaoshanense Qi, C. changyangense (Chang), Protocycloceras deprati Reed, P. hupehcnse (Shimizu and Obata), P. sichuanense Wang, P. remotum Lai, P. gangshanense sp. nov., P. siphosedimentum Pan, P. chaoi sp. nov., P.shishantouense sp. nov., P. gaojiabianense sp. nov., Changyangoceras gaojiabianense sp. nov., Gangshanoceras jurongense gen. et sp. nov., G. densum gen. et sp. nov., Michelinoceras cf. dayongense Lai, Troedssonella lunshanensis sp. nov., Mesosendoceras leei (Y), Vaginoceras peiyangense malukonense Chen, Dideroceras mui (Chang), D. gaoluncunense sp. nov.     

粤西云开地区中奥陶世翼形类(双壳类)一新超科——郁南蛤超科Yunannioideasuperfam. nov.

本研究记述粤西云开地区中奥陶统东冲组一种奇异的翼形类(双壳类)化石,建立了郁南蛤超科(新超科)Yunannioidea superfam.nov.,郁南蛤科(新科)Yunanniidae fam.nov.,郁南蛤属(新属)Yunannia gen.nov.及2新种:干坑郁南蛤(新属新种)Yunannia gankengensis gen.et sp.nov.和云开郁南蛤(新属新种)Yunannia yunkaiensis gen.et sp.nov..讨论了它们的内部构造特征及分类位置.     

The effects of the final stages of the Late Ordovician glaciation on marine palynomorphs (chitinozoans, acritarchs, leiospheres) in well Nl-2 (NE Algerian Sahara)

Palynomorph assemblages, especially chitinozoans and acritarchs, from the Upper Ordovician of well Nl-2 (north-east of the Algerian Sahara) are studied in order to precisely date the ultimate effects of the Late Ordovician glaciation and to document the impact of this major climatic stress on the diversity of the palynoplankton. References are made to stable isotope excursions and to global eustatic sea level variations in order to improve the local age determination. The Hassi el Hadjar Formation, i.e. glacio-marine diamictites, is interpreted as a transgressive event resulting from the melting of the northern Gondwana ice cap. It yields poorly preserved and moderately diverse chitinozoans of late Hirnantian age. Acritarchs are more abundant in the lower part of these "microconglomeratic clays", but display a low diversity and are badly preserved throughout the whole formation. Reworked individuals are recorded in both groups. The marine sediments of the M'Kratta Formation of latest Hirnantian age contain better preserved, more abundant and more diverse palynomorph assemblages, especially in the Upper Member. The composition of this palynoplankton indicates a fairly good faunal and phytoplankton recovery after the early Hirnantian climatic stress.The extinction of the Ordovician forms, and the appearance of Silurian type taxa occur only in the uppermost Hirnantian, i.e. following with a slight delay the glacial event. The overlying black shales of Wenlock age (lower part of the Oued Mehaiguène Formation) are indicative of marine anoxic environments. They yield a virtually exclusive, but enormous number of Tasmanacea. The very peculiar composition of this palynoplankton seems to be independent of the Late Ordovician glaciation and is most likely related to the factors that, later, generated and maintained anoxic conditions in this area.A new species of chitinozoan, Spinachitina oulebsiri sp. nov. from the latest Hirnantian M'Kratta Formation, is described and illustrated.     

峡东地区上奥陶统高庙坡组球节子类及其它多节类三叶虫

系统描述湖北宜昌和秭归新滩晚奥陶世庙坡组球接子类及多节类三叶虫动物群中的１４种,分属于９属、７科、。根据化石保存状态、挤压变形以及个体发育特征,对前人所报道的产于本组的有关三叶早作了大量归并、转移和重新厘定,新的材料支持解释Telephiana longicephala的性双形现象。Ａtractopyge系首次在庙坡组中发现,以往它在三峡地区只见于临湘组。文中还将新疆的一个保留命名种Ｌonchodomas cf.yohi重新命名为Ｌonchodomas zhangi sp.nov.。     

An Upper Ordovician chitinozoan biozonation in British Avalonia (England and Wales)

An Upper Ordovician chitinozoan biozonation for British Avalonia is established. The new scheme is based on chitinozoan faunas from the historical Caradoc- and Ashgill-type sections in the Anglo-Welsh area; these data are supplemented with information from other key British sections that have accurate graptolite control. As a result, the chitinozoan biozonation for British Avalonia is tied to both the British chronostratigraphical framework and the graptolite biostratigraphy. It consists of 13 chitinozoan bio(sub)zones and for the first time provides a formal chitinozoan biozonal scheme for the Upper Ordovician of Britain, which can be tied with the well-established biozonation in Baltoscandia. This predominantly Baltoscandic signature of the new British chitinozoan biozonation is consistent with Avalonia's northwards migrating palaeogeographical position during the Ordovician.     

Late paleocene flora of the northern Alaska Peninsula: the role of transberingian plant migrations and climatic change

For the first time, the Late Sagwon Flora is described from the upper beds of the Prince Creek Formation (Upper Paleocene) at the Sagavanirktok River (northern Alaska Peninsula). The flora is dominated by the angiosperm Tiliaephyllum brooksense Moiseeva et Herman sp. nov. and conifer Metasequoia occidentalis (Newb.) Chaney. The Late Sagwon Flora is most similar to the Danian or Danian-Selandian flora from the middle part of the Upper Tsagayan Subformation (Amur Region) and lower part of the Wuyun Formation (Heilongjiang Province, China). This similarity allows us to hypothesize that the genus Tiliaephyllum, which dominated in the Late Tsagayan Flora, migrated via the Bering Land Bridge from southern paleolatitudes of the Far East to high latitudes of the Arctic Pacific, due to the progressively warming climate of the Paleocene. Additional new angiosperm species are described from the Late Sagwon Flora: Archeampelos mullii Moiseeva et Herman sp. nov., Tiliaephyllum brooksense Moiseeva et Herman sp. nov., and Dicotylophyllum sagwonicum Moiseeva et Herman sp. nov.     

Discovery of rhombifera (Echinoderms) in the Ordovician of Mongolia

Two new rhombiferan species Echinosphaerites mongolicus sp. nov. and Stichocystis altaicus sp. nov., described from a recently discovered Upper Ordovician locality in the Mongolian Altai, on the Chegertei River, suggest possible biogeographic links between this region and Gondwana and Baltica in the Ordovician. In the Upper Ordovician beds in the East Gobi Depression near Saishand Well, we identified the crinoid Ristnacrinus, previously recorded from the Ordovician of Estonia and Central Asia.     

Early Silurian(Telychian)rugose coral fauna of Daguan area, northeast Yunnan Province,China

Study on rugose coral fauna of the Sifengya Formation(early Telyehian)and Daluzhai Formation (mid-late Telychian)in Daguan area,northeast Yunnan Province,China was carded out.Rugose coral fauna of the Sifengya Formation included 18 genera and 34 species,while Daluzhai Formation with nine genera,ten species.We described rugose coral fauna(12 genera,19 species)including one new genus and five new species,i.e.Protoketophyllum daguanense gen.et sp.nov..Crassilasma huanggexiense sp.nov.,Pseudophaulactis heae sp.nov.,P.convolutus sp.nov.,and Shensiphyllum minor sp.nov..The characteristics and geological significance of rugose coral fauna of Sifengya Formation and Daluzhai Formation were analyzed.Particularly,mgose coral fauna of the Sifengya Formation represent early Telychian rugosan fauna in the Upper Yangtze region and improve the sequences of early Silurian(Llandovery)mgose coral assemblages in Yangtze region.It is therefore very meaningful to further analyze radiation period of rugose coral fauna in such epoch.     

New brachiopod species from the order acrotretida from the Cambrian of central Kazakhstan

Four new brachiopod species from the order Acrotretida (class Lingulata): Picnotreta saryarkensis sp. nov., Stilpnotreta propria sp. nov., Anabolotreta firma sp. nov., and Batenevotreta variabilis sp. nov. are described from the Agyrek Mountains, northeastern Central Kazakhstan from two olistoliths of limestones, which contain the uppermost Middle and lowermost Upper Cambrian fauna and are located in the Upper Ordovician olistostrome. These new species supplement the described earlier brachiopod assemblage from this region (Koneva and Ushatinskaya, 2008). Strong age and intraspecific variability of some Kazakh acrotretids is shown.     

鄂尔多斯盆地南缘上奥陶统生物礁的层孔虫化石

文中系统描述了鄂尔多斯盆地南缘淳化县铁瓦殿、岐山县烂泥沟上奥陶统生物礁中的层孔虫化石,包括2目5属9种,分别为囊层孔虫(Cystistroma)、拉贝希层孔虫(Labechia)、穿孔层孔虫(Forolinia)、网格层孔虫(Clathrod ict yon)和蜂巢层孔虫(Ecclimadictyon).建立拉贝希层孔...     

Restudy of some Ordovician–Silurian boundary graptolites from Anticosti Island, Canada, and their biostratigraphic significance

The Ellis Bay Formation on Anticosti Island has long been recognized for the biostratigraphic importance of its latest Ordovician conodont, palynomorph, and shelly fossil assemblages. However, a sparse record of graptolites has made it difficult to correlate these assemblages with the graptolite biozonation. Restudy of some previously described and examination of newly collected normalograptid specimens from the Ellis Bay and lower Becscie formations, however, shows that biostratigraphically important taxa are present and these species provide important constraints on the age of the strata. Normalograptus parvulus and N. minor have been identified in the upper half of the Ellis Bay Formation, suggesting that these strata are late Hirnantian in age ( N. persculptus Biozone). Normalograptus imperfectus and Normalograptus sp. aff. N. acceptus occur in the basal beds of the Becscie Formation, indicating that these strata are earliest Silurian. These graptolite data support the hypothesis that the positive carbon isotope excursion seen in the uppermost strata of the Ellis Bay Formation is isochronous with that seen in the Hirnantian strata at Dob's Linn, Scotland, and does not span much of the lower to mid-Hirnantian, as is the case in Arctic Canada and Nevada, USA.     Anticosti Island , Hirnantian, graptolites, Ordovician, Silurian.     

A new Middle Ordovician conodont from central Kazakhstan, nothern Kyrgyzstan, and Altai

Naimanodus degtyarevi gen. et sp. nov., a new conodont genus and species from the Lower Darriwilian (Middle Ordovician) limestones of the Naiman Formation in central Kazakhstan is described. Three types of coniform nongeniculate elements are identified in the apparatus of this species. The new species was widespread in the Asian Paleobasin and recorded in three localities in Kazakhstan, eastern Kyrgyzstan, and Altai.