Late Darriwilian–early Katian (Ordovician) ostracods of northeastern Yunnan,Southwest China

Ordovician silicified ostracods of the western Yangtze Platform, South China, are documented for the first time from the Huadan Formation of Qiaojia County, northeastern Yunnan Province, Southwest China. Twenty-one species of 17 genera are identified with new taxa including Vendona spinifera n. sp. and Nikitinella songliangensis n. sp. These two species, together with Medianella gigantea are the most common constituents of the fauna. Faunal comparison shows close connections between South China, Baltica, the Argentine Precordillera, Kazakhstan, Tarim, and Sibumasu during this time interval. This fauna is considered to be related to a nearshore carbonate environment, and biostratigraphical analysis of it supports a late Darriwilian to early Katian age for the Huadan Formation.     

Earliest Devonian phacopide trilobites from central Bolivia

An early Lochkovian trilobite faunule from the Catavi Formation, Cochabamba Department, Bolivia, includesPaciphacops waisfeldae n. sp. andKazachstania gerardoi n. sp. The latter species also occurs in the upper part of the Los Espejos Formation in the Precordillera of San Juan, Argentina, and the former is sister species toP. argentinus (Thomas 1905) from the Los Espejos Formation. South AmericanPaciphacops species are allied to North American, rather than Australian, congenerics.Kazachstania Maksimova 1972 appears to include some species previously assigned toReussiana ?najdr 1987. Records ofPaciphacops andKazachstania provide evidence that earliest Devonian trilobites of Andean South America are largely geographically widespread taxa.     

Eine neue fragliche kalkschalige Foraminif ere aus einem mittelordovizischen Geschiebe Norddeutschlands

Calcareous foraminifers were hitherto unknown from the Ordovician of Baltoscandia. From an erratic Backsteinkalk boulder of Northern Germany (Middle Ordovician) a new bodily preserved questionable species ofGlomovertella is described.Glomovertella belongs to the questionable order of foraminifers Reitlingerellida and was known hitherto only from the Lower Cambrian of Siberia and the Caradoc of Kazachstan. The members of the Reitlingerellida were, until now, only known by thin sections.     

Early ordovician reefs from Argentina: Stromatoporoid vs stromatolite origin

Summary Late Arenigian biohermal reef mounds and biostromes within the shallow-marine platform facies of the upper San Juan Formation of the Precordillera (Western Argentina) represent a new Early Ordovician reef type. The meter-sized reefs are dominated byZondarella communis n.g. n. sp. The new taxon is characterized by domical, bulbous and laminar morphotypes exhibiting growth layers and thin horizontal and vertical as well as intermingled skeletal elements included within different sets. The fossil maybe compared with stromatolites and stromatoporoids but an interpretation as primitive stromatoporoids is favoured.     

Stratigraphical distribution of the Ordovician graptolite Azygograptus Nicholson & Lapworth in the Central Andean Basin (northwestern Argentina and southern Bolivia)

We analyzed new occurrences of Azygograptus lapworthi from the Cordillera Oriental, Argentina. The bearer sandstones levels, corresponding to the Acoite Formation, are overlying the deposits, in which the Didymograptellus bifidus Biozone (Lower Ordovician, upper Floian, Fl3) was previously recognized, and are overlain by younger pelitic levels yielding Xiphograptus lofuensis (Middle Ordovician, early Dapingian, Dp2). Previous records from the Central Andean Basin are also reviewed in detail and accurately correlated, allowing us to conclude that the Azygograptus lapworthi Biozone corresponds to the Middle Ordovician (lower Dapingian, Dp1). This biostratigraphic framework documents that the transition between the Lower and Middle Ordovician deposits occurs in the uppermost levels of the Acoite Formation in the Argentine Cordillera Oriental. It is additionally integrated with up to date conodont records to establish a high-resolution regional correlation, with equivalent deposits from the Puna of northwestern Argentina and Cordillera Oriental of Bolivia, and to discuss new insights for global correlation.     

New early Ordovician calcareous foraminifers of the middle Tien Shan

Twelve new species of calcareous foraminifers of the genera Parathurammina, Parathuramminites, Bisphaera, Archaesphaera, and Vicinesphaera from the Lower Ordovician of the Middle Tien Shan are described.     

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.     

Oysters and oyster-like bivalves from the Middle Triassic Muschelkalk of the Germanic Basin

Middle Triassic marine deposits of the Germanic Basin (Muschelkalk) record a significant proliferation of cementing bivalves from different families. Based on previously undescribed, excellently preserved material from the Willebadessen Member (late Anisian, Illyrian) of the Upper Muschelkalk Trochitenkalk Formation of Willebadessen (Germany), we propose the new genus Noetlingiconcha, type species N. speculostreum sp. nov., for strongly plicate prospondylids lacking auricles. The new genus differs from Terquemia and Enantiostreon in being plicate rather than costate, and from Newaagia in the absence of auricles. We demonstrate that N. speculostreum was invariably attached by its right valve, in contrast to an externally similar species from the Lower Muschelkalk Freudenstadt Formation (lower Anisian, Bithynian) that was exclusively cemented by its left valve and thus represents the geologically oldest known oyster species. Previous reports of amphi-pleurothetic cemented bivalve species from the Muschelkalk probably result from lumping together these two externally similar species. The constancy of sinistral attachment in the geologically oldest Ostreidae suggests that left-pleurothetic valve orientation was already established in the ancestry of this family. Palaeontological data are therefore in accordance with genetic and larval shell morphology analyses that identified Pterioidea as the sister taxon of Ostreoidea, because Pterioidea contains several Permian-Triassic genera with an anatomically lower left valve.     

Lower Ordovician microfacies and microfossils from Cerro San Pedro (San Pedro de la Cueva,Sonora, Mexico), as a westernmost outcrop of the newly defined <Emphasis Type="Italic">Nuia</Emphasis> Province

The lowermost carbonate beds of the Cerro San Pedro (San Pedro de la Cueva, Sonora State, Mexico) previously assigned to the Mississippian, belong in fact to the lower Ordovician. The limestone of this succession is often dolomitized and chertified, and displays gastropods, pelmatozoans, sponges, and trilobites as major bioclastic components. The different microfacies show that high-energy grainstones, proximal tempestites, and distal tempestites dominated the sedimentation. The paleoenvironments of deposition correspond to an inner ramp, a mid-ramp, and perhaps the upper part of an outer ramp. The strata are characterized by the incertae sedis cyanobacteria Nuia sibirica. A taxonomic revision and discussion of these cyanobacteria, often confused with ooidic grains, is emphasized. Some data are presented on other microfossils, such as primitive, monothalamous foraminifers: Rauserina sp., Vicinesphaera sp., and Neoarchaesphaera sp., leperditicopida and their endolithic microperforations, and primitive chaetetids. Compared to the contemporaneous deposits of the USA, some paleobiological components, e.g., the lithistid siliceous sponges Archaeoscyphia, stromatoporoids? Pulchrilamina, and receptaculacean algae Calathium, are quite rare in the studied section of Sonora, but the predominance of tempestites in the carbonate succession shows that boundstones formed before were systematically eroded and resedimented. The paleogeographic implications are the following: (1) a lower Ordovician intertropical Nuia Province is newly defined in the western part of the lower Ordovician intertropical belt; (2) San Pedro de la Cueva constitutes one of the westernmost outcrops of this new Nuia Province; (3) from Sonora, Nuia extends eastward as far as South China; (4) due to its westernmost paleoposition, San Pedro de la Cueva was frequently affected by tropical storms; and (5) northern lower Ordovician terranes of Mexico (Sonora, Chihuahua, and Baja California) are entirely distinct from the southern ones (Oaxaca). The paleopositions and paleogeographic connections of these northern Mexican terranes with Laurentia, Avalonia, and peri-Gondwanan parts of South America, through the Iapetus and Rheic oceans, still remain disputable or unknown.     

The oldest bryozoans of Baltoscandia from the lowermost Floian (Ordovician) of north-western Russia: two new rare,small and simple species of Revalotrypidae

We describe two new species of esthonioporate bryozoans, Revalotrypa inopinata sp. nov. and R. yugaensis sp. nov., from the Lower Ordovician, south-east of Lake Ladoga, north-western Russia. The colonies of the two species are very small and were extracted from limestone nodules found in the lower part of glauconitic sandstone in the Joa Member (lowermost Floian). Revalotrypa inopinata sp. nov. and R. yugaensis sp. nov. are the oldest known bryozoans from Baltoscandia. Study of the two species includes scanning electron microscopy (SEM) imaging and X-ray microtomography (micro-CT). The palaeogeographic distribution of the oldest known bryozoans from the Lower Ordovician and the advantages and disadvantages of micro-CT for the study of Palaeozoic bryozoans are discussed. The authorship of Revalotrypidae, which has been inconsistently allocated in the literature, is discussed.     

The earliest known estuarine bivalve assemblage, Lower Ordovician of northwestern Argentina

The oldest known estuarine bivalve assemblage is documented from the Lower Ordovician (upper Arenig-lower Llanvirn) Alto del Cóndor Formation, which crops out in the Cordillera Oriental of northwestern Argentina. This unit displays most of the diagnostic sedimentary attributes of estuarine environments. Biotic components include low-diversity trace fossils and a peculiar bivalve fauna consisting of the new genera Konduria, Pseudoredonia, and Pucamya, and the new species Redonia condorensis. This constitutes the earliest known occurrence of bivalves in brackish waters, suggesting that the capability of this clade to colonize estuarine environments developed early in their radiation.     

Lower Darriwilian radiolarians from the Argentine Precordillera

The first radiolarians discovered in the Ordovician of the Argentinian Precordillera are reported. The material is associated with conodonts indicating the upper part of the Lenodus variabilis Biozone (Lower Darriwilian, Da1-2). The low diversity radiolarian fauna shows similarities with Middle Ordovician radiolarians from the Akzhal Mountains of Kazakhstan. However, a close comparison is difficult due to the poor preservation of the material, in which internal structures of the radiolarian tests are not preserved.     

First report of craniide brachiopods in the Palaeozoic of Iran (Pseudocrania,Ordovician), and Early to Mid‐Ordovician biogeography of the Craniida

Abstract: Lower Ordovician faunas of Bohemia (Perunica), Baltica and North China include the oldest known representatives of the Order Craniida, but otherwise in Gondwana and associated terranes, the record of craniides is sparse. Pseudocrania insperata sp. nov. from the Lashkarak Formation of the Eastern Alborz Mountains is the first and as yet only record of the occurrence of craniides in the Middle Ordovician (Darriwilian) of Iran and temperate to high latitude peri‐Gondwana. Pseudocrania was known hitherto only from the Middle Ordovician of Baltoscandia and the Chu‐Ili terrane of Kazakhstan.     

Palynostratigraphical dating of the Lower Cretaceous Peñaferruz Formation,San Pedro de Antromero Beach (Asturias Region,northwestern Iberian Peninsula)

A palynological assemblage of five Lower Cretaceous stratigraphic levels corresponding to the Peñaferruz Formation in San Pedro de Antromero Beach, has been studied to determine the exact age of this formation. An age no older than the Aptian is suggested on the basis of the palynoflora, based on the presence of Trilobosporites hannonicus, Cicatricosisporites venustus, Cicatricosisporites berouensis, Ephedripites dudarensis, and Reticulisporites semireticulatus. This age assignment implies a new relationship between the Peñaferruz and Antromero formations, the Peñaferruz Formation being younger than previously thought. This possibly makes both formations contemporaneous, at least at the San Pedro de Antromero Beach section, suggesting a lateral change of facies between these deposits.     

Stratigraphic distribution of selected acritarchs in the Ordovician subsurface,Canning Basin,Western Australia

Palynological investigation of 80 core samples from four boreholes, drilled through the Lower to Middle Ordovician marine sections of the central-northeastern Canning Basin, northwestern Australia, reveals diverse acritarch associations including a number of stratigraphically significant species. The stratigraphic succession studied, embracing the Willara Formation and conformably overlying Goldwyer Formation, has been independently dated as early Arenig to Llanvirn by conodont faunas (Oepikodus communis through Phragmodus-Plectodina zonal interval). Nine morphologically distinctive acritarch species have relatively narrow vertical ranges within the study interval and likely constitute serviceable palynostratigraphic indices for the Ordovician in and possibly beyond the Western Australian study area. Three new species, Comasphaeridium setaricum, Polyancistrodorus kunzeanensis, and Stelomorpha calix, are established; and one new combination, Baltisphaeridium variocavatum (Playford and Martin, 1984), is proposed. Other stratigraphically significant species include Petaloferidium comptum Playford and Martin, 1984 and Peteinosphaeridium sp. cf. P. exornatum Tongiorgi et al., 1995; together with Dorsennidium symmetricum (Lu, 1987) Sarjeant and Stancliffe, 1994, Peteinosphaeridium coronula Yin et al., 1998, and Striatotheca rarirrugulata (Cramer et al., 1974) Eisenack et al., 1976, which are found for the first time in Australia. The vertical distribution, and hence the stratigraphic utility, of each of the above species is documented through the studied sections.     

Discovery of Anticostia uniformis from the Xiazhen Formation at Zhuzhai,South China and its stratigraphic implication

The Xiazhen Formation is an Upper Ordovician lithostratigraphic unit in the Jiangshan-Changshan-Yushan (JCY) area, which contains series of Late Ordovician reef successions. The reef successions of the Xiazhen Formation at Zhuzhai are critical for evaluation of the Late Ordovician marine diversity and palaeoecology. However, their age has long been uncertain and generally is regarded as of upper Katian, based on the occurrences of shelly fossils and correlation with the stratigraphic equivalent Changwu Formation. The newly discovered graptolite species Anticostia uniformis, in the Xiazhen Formation, together with the combined evidence of brachiopods and sedimentology, indicates an age range for the graptolite locality from the Dicellograptus complanatus Biozone to the Diceratograptus mirus Subzone of late Katian, but the graptolites do not rule out the possibility that it is Hirnantian.     

Timing and progression of the end-Guadalupian crisis in the Fars province (Dalan Formation, Kuh-e Gakhum, Iran) constrained by foraminifers and other carbonate microfossils

The Middle-to-Upper Permian in the Kuh-e Gakhum anticline (southeastern Iran) has rarely been studied due to its structural complexity and the difficult access. Rich Permian fusulinid assemblages varying in age from Wordian to Changhsingian were found in a thick carbonate succession corresponding to the Dalan Formation. Three new species of foraminifers are described and a new biostratigraphic framework including five biozones is proposed. One of these, described and defined for the first time in the Dalan Formation, is based on the presence of Praedunbarula simplicissima n. gen. n. sp. When compared to the fossil content of existing bioprovinces, the floro-faunal biota of the Dalan Formation shows an affinity with Central and Western Tethys. A mass extinction of fusulinids and small foraminifers (70%) occurred concomitantly with the onset of a relative sea-level fall. This event led to a change in the carbonate factories from biologically induced carbonate production to ooid-rich chemically induced precipitation. The morphology of the platform at the Guadalupian/Lopingian transition evolves from a bioclastic ramp to a shelf. This transition is also characterized by a major sequence boundary and morphological anomalies in foraminifers. Therefore, as the regression and the changes in floro-faunal contents have been observed at the Guadalupian/Lopingian boundary, the extinction event is considered as end-Guadalupian. It is followed by a Lopingian transgression yielding renewed foraminiferal assemblages.     

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.     

Preliminary palaeobotanical notes on the Early Cretaceous Cintura Formation (Sonora,Mexico)

The Cintura Formation of Albian–Cenomanian age in the Cabullona Basin yielded an important fossil flora, including palynomorphs, leaf impressions and fossil trunks. At the base of the Marquechi Member a poorly preserved palynomorph assemblage is recognised. The palynological assemblage is dominated by gymnosperms, mainly by cheirolepidiacean genus Classopollis. A noteworthy feature is the presence of angiosperm pollen grains of the genera Clavatipollenites, Retimonocolpites and Tucanopollis. A rich, diverse and well-preserved macroflora of leaf impressions has been observed in the uppermost part of this formation belonging to the San Juan Member. There are at least eight morphospecies of leaves including an abundance of taxa with possible botanical affinities to the family Sapindaceae. The angiosperm pollen grains together with the sapindalean leaves constitute the oldest record of such remains in Mexico.