Microaerophilic Fe‐oxidizing micro‐organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians,Romania)

Ferruginous stromatolites occur associated with Middle Jurassic condensed deposits in several Tethyan and peri‐Tethyan areas. The studied ferruginous stromatolites occurring in the Middle Jurassic condensed deposits of Southern Carpathians (Romania) preserve morphological, geochemical, and mineralogical data that suggest microbial iron oxidation. Based on their macrofabrics and accretion patterns, we classified stromatolites: (1) Ferruginous microstromatolites associated with hardground surfaces and forming the cortex of the macro‐oncoids and (2) Domical ferruginous stromatolites developed within the Ammonitico Rosso‐type succession disposed above the ferruginous microstromatolites (type 1). Petrographic and scanning electron microscope (SEM) examinations reveal that different types of filamentous micro‐organisms were the significant framework builders of the ferruginous stromatolitic laminae. The studied stromatolites yield a large range of δ⁵⁶Fe values, from ?0.75‰ to +0.66‰ with predominantly positive values indicating the prevalence of partial ferrous iron oxidation. The lowest negative δ⁵⁶Fe values (up to ?0.75‰) are present only in domical ferruginous stromatolites samples and point to initial iron mobilization where the Fe(II) was produced by dissimilatory Fe(III) reduction of ferric oxides by Fe(III)‐reducing bacteria. Rare‐earth elements and yttrium (REE + Y) are used to decipher the nature of the seawater during the formation of the ferruginous stromatolites. Cerium anomalies display moderate to small negative values for the ferruginous microstromatolites, indicating weakly oxygenated conditions compatible with slowly reducing environments, in contrast to the domical ferruginous stromatolites that show moderate positive Ce anomalies suggesting that they formed in deeper, anoxic–suboxic waters. The positive Eu anomalies from the studied samples suggest a diffuse hydrothermal input on the seawater during the Middle Jurassic on the sites of ferruginous stromatolite accretion. This study presents the first interpretation of REE + Y in the Middle Jurassic ferruginous stromatolites of Southern Carpathians, Romania.     

Paleoenvironmental and diagenetic implications of δO and δC isotope ratios from the Upper Jurassic Plassen limestone (Northern Calcareous Alps, Austria)

The first δ¹⁸O and δ¹³C data from the Upper Jurassic of the Northern Calcareous Alps are presented. The interpretation of stable isotope ratios serves as an approach for paleoenvironmental and diagenetic studies of the Plassen carbonate platform, which cannot be obtained by paleontological methods and microfacies analyses alone. The studied part of the Plassen limestone is characterized by (1) lithoclast facies, also called ‘intraformational breccia’; the origin of lithoclasts was formerly unknown; (2) peloid facies; (3) bioclastic facies, composed of peloids, porostromate algae, green algae and red algae; and (4) oncoid facies. Two types of fracturing and four cement generations can be distinguished. Isotope ratios of the matrix, oncoids, three cement generations and whole rock samples revealed that (1) the studied section represents an open marine carbonate platform with high water circulation and high input of cool oceanic waters; (2) the platform was not affected by emersion and fresh water influence; normal marine conditions prevailed; (3) carbonate cements were precipitated in a closed diagenetic system, but burial diagenesis was absent; (4) both fabric-selective and non-fabric-selective fracturing occurred in a normal marine environment, affecting the formation of ‘intraformational breccias’.     

A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs

Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates.     

New species of stenolaemate bryozoans from the Jurassic of the Moscow and Saratov Regions (Russia)

Three new species of the Middle Jurassic stenolaemate bryozoans of the genera Reptomultisparsa d’Orbigny and Microeciella Taylor et Sequeiros are described: R. saratovensis sp. nov. and M. seltseri sp. nov. from the Lower Bathonian and the Upper Callovian of the Saratov Region, respectively, and R. stupachenkoi sp. nov. from the Middle Callovian of the Moscow Region. Some specific features of their astogeny and colonial morphology are discussed.     

Fossil plant evidence for Early and Middle Jurassic paleoenvironmental changes in Lanzhou area, Northwest China

Estimating the paleoclimate changes through CO₂ levels has become a promising area of geological research. This paper focuses on analysis of fossil Ginkgo in continuous sedimentary series in northwestern China using plant anatomy and organic geochemistry approaches. The CO₂ variation curve during Early and Middle Jurassic is reconstructed based on the stomatal ratio method, which is consistent with the estimated results of GEOCARB III. In comparison with the carbon isotopic composition measured from the fossil leaves of Ginkgo, we suggest that the stomata-based CO₂ concentrations for the Jurassic are generally consistent with the predictions of the geochemical model, ranging from 1000 to 1600 ppmv. Measurements of carbon isotope values demonstrate that the water use efficiency of the fossil Ginkgo in a “green house” world is higher than that of the living Ginkgo. Investigations of physiological responses of plants to the increasing CO₂ level at the present and in the future should help demonstrate this effect. The cause of the carbon isotopic shift at the boundary between Aalenian and Bajocian for the Yaojie Basin is unclear and therefore needs further investigation.     

Bryozoans of the genera Stomatopora Bronn and Stoporatoma gen. nov. (Stenolaemata) from the Middle Jurassic of Moscow City and the Moscow Region

Encrusting uniserial bryozoans are recorded from the Middle Callovian of Moscow city and the Moscow Region: Stoporatoma gerasimovi gen. et sp. nov. and three species of the genera Stomatopora Bronn; i.e., S. dichotoma (Lamouroux), S. waltoni Haime, and S. bajocensis (Orbigny). Some morphological characters and environmental conditions of these bryozoans are discussed. A new bryozoan that is characterized by a large size and distinctive circular reptozooecia is described.     

Representatives of the genus Ammosiphonia He, 1977 (Foraminifera) from the Jurassic and Carboniferous of Western Siberia

The wide distribution of the genus Ammosiphonia in the Upper Jurassic and Carboniferous of Western Siberia is established for the first time. Six haplophragmoidid species of Western Siberia are assigned to this genus. The diagnosis of the genus is emended; the taxonomic positions and scopes of the species Ammosiphonia nonioninoides (Reuss), A. beresoviensis (Bulatova), and A. sibirica (Zaspelova) are revised; two new species, A. suprajurassica sp. nov. and A. valanginica sp. nov., are described.     

Analysis of Late Jurassic to Early Cretaceous algal debris-facies of the Plassen carbonate platform in the Northern Calcareous Alps (Germany,Austria) and in the Kurbnesh area of the Mirdita zone (Albania): a tool to reconstruct tectonics and palaeogeography of eroded platforms

A characteristic microfacies of the Late Jurassic to Early Cretaceous allodapic Barmstein Limestone of the Northern Calcareous Alps are clasts of wackestones with numerous fragments of calcareous algae (“algal debris-facies”). According to dasycladale palaeocoenoses, several subtypes comprising different associations can be distinguished. One association is characterized by the debris of an unknown large dasycladalean alga reported as dasycladalean alga indet. sp. 1 from different localities in the Northern Calcareous Alps, typically forming a monospecific assemblage. Another microfacies type contains star-like calcitic bodies tentatively referred to the morphospecies Coptocampylodon pantici Ljubović-Obradović and Radoičić, originally described as being from the Turonian of NW-Serbia. Other Coptocampylodon-like bodies represent the calcified tufts of the laterals of Selliporella neocomiensis (Radoičić). The occurrence of Coptocampylodon pantici-like microfossils in the Late Tithonian to Early Berriasian, shows that obviously different species of dasycladaleans display identical to similar shaped tufts of laterals in transverse sections when becoming fragmented. Coptocampylodon pantici Ljubović-Obradović and Radoičić was observed only from different occurrences of Barmstein Limestone, but not from the autochthonous platform carbonates of the Plassen carbonate platform. The Coptocampylodon algal debris-facies is also reported from the Late Jurassic of Albania, Mirdita zone. Occurrences of different types of algal debris-facies in components of mass-flow deposits can be used as a tool to reconstruct eroded carbonate platforms and tectonics, as demonstrated in the Northern Calcareous Alps and the Albanides. Finally, the general occurrences of algal debris-facies in both settings—intra-Tethyan mostly isolated platforms (Alps, Albanides) vs. extended epeiric platforms (Middle East)—are compared and discussed.     

Two new species of Archaeohelorus (Hymenoptera,Proctotrupoidea, Heloridae) from the Middle Jurassic of China

Two new fossil species, Archaeohelorus polyneurus sp. n. and A. tensus sp. n., assigned to the genus Archaeohelorus Shih, Feng & Ren, 2011 of Heloridae (Hymenoptera), are reported from the late Middle Jurassic, Jiulongshan Formation of Inner Mongolia, China. Based on the well-preserved forewings and hind wings of these specimens, the diagnosis of the Archaeohelorus is emended: forewing 2cu-a intersecting Cu and Rs+M at the same point or postfurcal, and hind wing may have tubular veins C, Sc+R, R, Rs, M+Cu, M and Cu distinct, or simplified venation. The new findings also elucidate the evolutionary trend of forewing and hind wing venation and body size for the Heloridae from the late Middle Jurassic to now.     

A second specimen of the pterosaur<Emphasis Type="Italic">Anurognathus ammoni</Emphasis>

A new complete and fully articulated specimen of the anurognathid pterosaurAnurognathus ammoni from the Upper Jurassic Solnhofen Limestone of southern Germany provides new information about the species. The skull is broader than long and quite tall. The naris and antorbital fenestra are both small and anteriorly placed, whereas the orbit is very large. The palatal elements are slender struts of bone separating large openings. The tail is short, but is neither pygostyle-like nor like that of pterodactyloids. The wingfinger, unlike that of almost all pterosaurs, is reduced to three phalanges. Pedal digit V bears two long phalanges. Reexamination of the holotype specimen revealed evidence of bony bumps on the premaxilla and dentary that may have been associated with a fringe of bristles around the mouth.Anurognathus and the other anurognathids were probably adapted to aerial insectivory in low light conditions like extant caprimulgids and insectivorous bats, and may have spent little time on the ground. The taxonomy of the Anurognathidae is reviewed and new diagnoses are presented. A cladistic analysis supports the interpretation that the Anurognathidae is the sister-group to all other pterosaurs.      

Diet of prosauropod dinosaurs from the late Triassic and early Jurassic

Prosauropods were not scavenger-predators, rather they were the dominant large terrestrial herbivores during the late Triassic and early Jurassic. The herbivorous adaptations of anchisaurids include spatulate teeth with anteroposteriorly expanded crowns (maximum width apical to base of crown) which are obliquely inclined with respect to the jaws so each slightly overlaps the tooth behind it, and which have coarse marginal serrations at 45° to the cutting edges. Most of the teeth of yunnanosaurids lack serrations and resemble those of sauropod dinosaurs in form and in having self-sharpening surfaces, formed by tooth-to-tooth wear, which increased the efficiency of dealing with more resistant plant material. Anchisaurids and yunnanosaurids had a ventrally set jaw articulation; the teeth and skull of melanorosaurids are unknown. All prosauropods were high browsers that extended the feeding range with a long neck and tripodal feeding (long hindlimbs and stout tail for support). They used herding and the enormous claw on the pollex for defense, and probably had a muscular gastric mill with stones that was used for grinding the food. They account for at least 95% of the biomass in their respective faunas.     

Two new aero-aquatic species of the hyphomycete genusHelicodendron from Austria

Two new aero-aquatic species of the genusHelicodendron are described and illustrated:H. coniferarum andH. longitubulosum spp. nov. Both belong to the ecological group of the aero-aquatic fungi which inhabit submerged litter in stagnant pools and ditches. The new species are compared with similar species (H. coniferarum withH. fuscum, H. cumbriense, H. multiseptatum andH. pinicola;H. longitubulosum withH. tubulosum andH. longisporum). In addition, ecology and substrates are recorded: WhereasH. coniferarum was isolated from pine litter submerged in oligotrophic peat bog ditches,H. longitubulosum grew on an oak leaf submerged in a eutrophic woodland pond. The presence of microconidia inH. longitubulosum is discussed.     

Oncoid-dwelling foraminifera from Late Jurassic shallow-water carbonates of the Northern Calcareous Alps (Austria and Germany)

Oncoidal limestones with different oncoid types are ubiquitous in back-reef open-lagoonal and, to a minor amount, in closed-lagoonal facies of the Late Jurassic Plassen Carbonate Platform of the Northern Calcareous Alps. A common feature of the oncoids from moderately to well-agitated open-lagoonal habitats are incorporated small trochospiral benthic foraminifers, tentatively assigned to trochamminids, switched between individual micritic layers. Their life style is discussed concluding a specialized feeding on cyanophytes on the outer side of the oncoids and later becoming biomurated by successive sheet formations due to oncoid growing.     

Distribution and palaeoecology of freshwater algae and stromatolites: III, some new forms from the Carboniferous, Permian and Triassic of France and Spain

New collections allow us to describe some new algae forming: a) centimetric, unorganized, masses (Toutinella bifurcata from the Middle Triassic of Provence); b) large, decimetric masses (Zarramanella menorica from the ‘Buntsandstein’ of Minorca, Balearic Islands) and c) interesting, plurispecific biocenosis, laminated and silicified, from the French Massif Central: Lower Stephanian of Saint-Étienne basin (with Hankerpella minima, Baltzerella stephaniense, Ponsinella undulata) and Lower Autunian of Bourbon-l'Archambault basin (Hanskerpella pustulata, Baltzerella stephaniense, Ponsinella multifrons, Sarfatigirella intricata). Other forms are badly preserved, one is possibly a Broutinella sp. and another may be a coccoid form of cyanobacteria or chlorophyceae. Silicified biocenoses macroscopically occur in the form of regular laminations, exhibiting vertical, planar joints (1–2 cm wide) and horizontal, planar joints, 5 mm to 3 cm thick, with various sedimentary infillings. These facies represent early and late silicifications of biological felts (mats), probably previously partly calcified and affected by desiccation cracks partly infilled before the silicification. There is no evidence for an early silicification of living filaments and trichomes. The silicification also affects other types of sediments (petites, sandstones, conglomerates, breccias) associated with the algal formations. Macroscopically, these laminated formations do not show domes or hemispheres; on the other hand, these features clearly appear under the microscope, and these formations are true stromatolites. The basins of Saint-Étienne and Bourbon-l'Archambault contain volcanic rocks; the siliceous series, very localized in the basins, represent an impregnation of various primary materials by silica of hydrothermal origin. The present study is voluntarily limited to the palaeontological and palaeoecological appearances; algal laminations formed in ephemeral pools and small lakes, under very particular conditions, ‘hydrothermal’ sensu lato, are still to be stated more precisely.

Résumé

Des récoltes nouvelles permettent de décrire quelques algues nouvelles formant des amas centimétriques non organisés (Toutinella bifurcata du Trias moyen de Provence), de grosses masses décimétriques (Zarmmanella menorica du Buntsandstein de Minorque) et d'intéressantes biocrenoses plurispécifiques laminées et silicifiées du Massif central français: Stephanien inférieur de Saint-Étienne (à Hankerpella minima, Baltzerella stephaniense, Ponsinella undulata), Autunien inférieur du bassin de Bourbon-l'Archambault (Hanskerpella pustulata, Baltzerella stephaniense, Ponxinella multifrons, Sarfatigirella intricata). D'autres formes sont mal conservées, l'une serait attribuables à une ? Broutinella sp. et une autre à une coccoide (cyanobactéries ou chlorophycées). Les biocœnoses silicificées se présentent macroscopiquement sous forme de laminations régulières, accidentées de fentes planes verticales (1–2 cm de largeur) et de fentes planes horizontales (5 mm–3 cm de hauteur), à remplissages sédimentaires variés. Ces faciès correspondent à des silicifications précoces et tardives de feutres biologiques probablement en grande partie calcifiés précocement et affectés de fentes de dessiccation partiellement remplies avant la silicification. Aucun indice de silicification de filaments et de trichomes du vivant des organismes n'a pu être observé. La silicification affecte aussi d'autres sédiments (pélites, grès, conglomérats, brèches), associés aux anciennes formations algaires. Macrospiquement, ces formations laminées ne montrent pas de dômes ni d'hémisphères; en revanche ces structures apparaissent parfaitement au microscope, et ce sont de véritables stromatolites. Les bassins de Saint-Étienne el de Bourbon-l'Archambault contiennent des formations volcaniques; les formations siliceuses, qui sont très localisées dans les bassins, correspondent certainement à une imprégnation par de la silice d'origine hydrothermale de sédiments variés. La présente étude se limite volontairement à l'aspect paléontologique et paléoécologique; les laminations algaires se sont formées dans des bassins ou de petits lacs éphémères, dans des conditions très particulières, hydrothermales sensu lato, encore à préciser.     

Middle to Late Holocene vegetation history of the Upper Engadine (Swiss Alps): the role of man and fire

To reconstruct the vegetation and fire history of the Upper Engadine, two continuous sediment cores from Lej da Champfèr and Lej da San Murezzan (Upper Engadine Valley, southeastern Switzerland) were analysed for pollen, plant macrofossils, charcoal and kerogen. The chronologies of the cores are based on 38 radiocarbon dates. Pollen and macrofossil data suggest a rapid afforestation with Betula, Pinus sylvestris, Pinus cembra, and Larix decidua after the retreat of the glaciers from the lake catchments 11,000 cal years ago. This vegetation type persisted until ca. 7300 cal b.p. (5350 b.c.) when Picea replaced Pinus cembra. Pollen indicative of human impact suggests that in this high-mountain region of the central Alps strong anthropogenic activities began during the Early Bronze Age (3900 cal b.p., 1950 b.c.). Local human settlements led to vegetational changes, promoting the expansion of Larix decidua and Alnus viridis. In the case of Larix, continuing land use and especially grazing after fire led to the formation of Larix meadows. The expansion of Alnus viridis was directly induced by fire, as evidenced by time-series analysis. Subsequently, the process of forest conversion into open landscapes continued for millennia and reached its maximum at the end of the Middle Ages at around 500 cal b.p. (a.d. 1450).     

Genus <Emphasis Type="Italic">Eckhardites</Emphasis> Mitta (Cardioceratidae,Ammonoidea) from the Lower Callovian of the subboreal Jurassic

The genus Eckhardites Mitta 1999, with the type species Macrocephalites pavlowi Smorodina, 1928 is discussed and its diagnosis and assignment to the family Cardioceratidae are substantiated. Eckhardites is compared to the genus Macrocephalites Zittel (family Sphaeroceratidae), to which some workers presently assign the type species of Eckhardites. Three species of Eckhardites are recorded from the basal Callovian elatmae Zone of the Russian Platform, one of which (E. menzeli (Mönnig)) was originally described from the synchronous beds in Germany. A new species E. dietli sp. nov. is described.     

A stegosaur vertebra (Dinosauria: Ornithischia) from the Callovian (Middle Jurassic) of Sarthe, western France

A dinosaur vertebra found in the course of road works in the “Chevain Marls” (marine Callovian) of the Vermont outlier, near the village of Béthon (Sarthe, Pays-de-la-Loire, western France) is described and referred to a stegosaur (cf. Lexovisaurus). It is the first record of a dinosaur in the Middle Jurassic of that area. The specimen was probably derived from the floating carcass of an animal that had lived on the emerged areas of the Armorican Massif, near which the Chevain Marls were deposited. This fossil is an addition to the short list of stegosaur remains reported from France.     

The significance ofSaccocoma-calciturbidites for the analysis of the Polish epicontinental late Jurassic Basin: An example from the Southern Cracow-Wielun Upland (Poland)

Summary In the top section of the Upper Jurassic profile in the S part of the Cracow-Wielun upland there occur deposits with numerous fragments of the plantonic crinoidsSaccocoma. Sedimentary structures indicate that these deposits are calciturbidites with domination of the redeposited pelagic material. TheSaccocoma-calciturbidites rest on the slope beds of Oxfordian cyanobacterial-sponge carbonate buildups formed in the Polish epicontinental basin, bordering the Tethys ocean in the north. The occurrence of the planktonicSaccocoma seems to be connected with a short deepening the S part of the Polish epicontinental basin in the Late Jurassic. This deepening caused the change within biocoenoses thriving in carbonate buildups and was mainly expressed in reducingTubiphytes. ‘Tubiphytes-reefs’, representing the last stage in the development of the carbonate buildups in the S part of the Cracow-Wielun upland, marked the most shallow sedimentation environment. With deepending of the basin,Tubiphytes and other benthonic forms disappeared, and, simultaneously, the dominant fauna became planktonic. The abundance of planktonic crinoidsSaccocoma (=Lombardia), as well as the presence of planktonic foraminifers, nannoplankton cf.Schizosphaerella, coccoliths and radiolarians indicates a pelagic, open-sea depositional environment. TheSaccocoma-dominated sediments, which had been primarily deposited from a suspension on a sea floor with a distinct relief, became subsequently transported by turbidity currents. A limited extent and thickness of theSaccocoma-calciturbidites was caused by a relatively small amount of the primary material which could be transferred by the turbidity currents because the period of pelagic sedimentation was short. TheSaccocoma-calciturbidites indicate a distinct shift in conditions of sedimentation resulting from over-regional changes and, despite the lack of index fossils, seem to represent a local lithostratigraphic horizon. These sediments probably mark a sedimentation event which caused a minor levelling of the sea floor relief. Then, after a sedimentation break, wide-spread destruction of the tops of carbonate buildups and formation of debris flows in the shallowing Late Jurassic sea took place. TheSaccocoma-calciturbidites in the S part of the Cracow-Wielun upland can be found near edges of horsts. This suggests that the foundations of these horsts are probably of sedimentary origin, dating back at least to the Late Jurassic. TheSaccocoma-calciturbidites in the S part of the Polish epicontinental basin seem to result from local, synsedimentary tectonic movements, which probably reflect over-regional events on the one hand, and oscillations of the sea level-on the other.     

Vertical distribution of an ectomycorrhizal community in upper soil horizons of a young Norway spruce (Picea abies [L.] Karst.) stand of the Bavarian Limestone Alps

The vertical niche differentiation of genera of ectomycorrhiza (ECM) was assessed in a 17-year-old Norway spruce (Picea abies [L.] Karst.) plantation on a mountainous dolomitic site (1,050 m above sea level) of the Bavarian Limestone Alps. We determined ECM anatomotypes, recorded the abundance of corresponding ECM root tips and classified them into groups of ECM exploration types, which refer to the organisation and the extent of their extramatrical mycelia. The abundance of ECM was highest in the organic soil layers, compared to the mineral soil horizon. The ordination of the ECM communities and of the exploration types revealed segregation related to soil horizon properties. While Cenococcum geophilum preferred the organic soil layers, Lactarius spp., Tomentella spp. and Craterellus tubaeformis were generally most abundant in the mineral soil horizons. Cenococcum geophilum was the predominant species, possibly based on enhanced competitiveness under the prevailing site conditions. The short-distance exploration types (e.g. C. geophilum) preferentially colonised the organic soil layer, whereas the contact types (e.g. most of the Tomentella spp., C. tubaeformis) together with medium-distance types (e.g. Amphinema byssoides) were primarily associated with the underlying A-horizons. Therefore, the soil horizons had an important effect on the distribution of ECM and on their community structure. The spatial niche differentiation of ECM genera and exploration types is discussed in regard to specific physico-chemical properties of soil horizon and the assumed ecophysiological strategies of ECM.