Hasil untuk "Paleontology"

STEFANO VISENTIN, GIULIA FAUCHER, Elisabetta Erba

Calcareous nannofossil biostratigraphy was conducted in the Toarcian-lower Bajocian interval at Colle di Sogno (Lombardy Basin, Southern Alps, Northern Italy) where the type-section of the Sogno Formation consisting of pelagic marly limestone, marlstone and marly claystone was established. Semiquantitative analyses of calcareous nannofossil assemblages allowed to achieve a high-resolution biostratigraphy based on several biohorizons, including zonal/subzonal markers and additional events. The NJT5 to NJT9 Zones of the standard nannofossil zonation established for the Mediterranean Province were identified. The biostratigraphy obtained at Colle di Sogno was compared to published nannofossil events calibrated with ammonite zones in sections from SE Spain, S France, Portugal and N Algeria. This assessment evidenced some discrepancies in the succession of events of the standard zonation and, furthermore, resulted in the revision of the age of a few datums. Moreover, some new/additional nannofossil biohorizons are proposed as subzonal markers. A morphometric analysis of the genus Watznaueria was conducted to identify diagnostic features for unambiguous species identification. The species W. colacicchii and W. contracta are distinguished on the basis of the coccolith width/central area width ratio, whereas W. britannica britannica is discriminated by the size - as in the original definition of the species - relative to the new subspecies W. britannica minor. The new species W. gaetanii differs from all other Watznaueria taxa by the bridge ultrastructure. In the Toarcian-Aalenian interval a progressive increase in size of Watznaueria specimens is paralleled by the progressive closure of the central area and the modification of the central area structure passing from a cross (W. colacicchii and W. contracta) to a double-button bridge (W. gaetanii) to a single-button bridge (W. britannica). These intrageneric evolutionary innovations accelerated in the Aalenian under stable paleoceanographic conditions and an oligotrophic regime.

Esperanza Cerdeño, Natalia P. Lucero, Jorge O. Chiesa

This is an updated contribution to the Quaternary geology and paleontology from central-western Argentina, focused on San Luis Province. It is mostly based on unpublished data; only some fossils had previously been briefly mentioned in broader faunal contexts. The fossil-bearing sediments correspond to eolian and alluvial environments of moderate energy, dominated by sands and sandy silts. They overlie high-energy fluvial cycles and underlie edaphic horizons. They have a wide distribution, and several radiocarbon dates allow their regional correlation. Stratigraphic sequences with the precise origin of fossils allow for the improvement of lithostratigraphic and faunal correlations with the Pampean Region (central and east Argentina; La Pampa and Buenos Aires provinces), where Pleistocene assemblages are better known, but also with central-western (Cuyo Region), northwestern, and northeastern Argentina. Faunal remains correspond to large mammals, represented by xenarthrans (Cingulata and Tardigrada), macraucheniids (Litopterna), gomphotheres (Proboscidea), and equids (Perissodactyla), a typical Pleistocene mixture of native (xenarthrans and litopterns) and immigrant mammals.

Nikolaos Dimopoulos, Elena Zoumpouli, Nicolina Bourli et al.

The studied section, up to 10 m thick with 17 different carbonate beds, showed the interaction between a giant slide and the pre-existing normal faults during the upper Cretaceous time. There are three major points of consideration in the studied section: (1). The presence of two slump horizons, up to 1 m thick each, within the stratigraphic column, related to the basin floor instability, due to normal listric faults activity. (2). The presence of many normal, with listric geometry, faults, with an ESE–WNW direction, and mostly west-dipping. These faults acted during the sedimentation processes and produced the basin floor inclination for the slumping when still the sediments were unconsolidated. This tectonic activity seems to terminate in the upper part of the stratigraphic column. (3). After the development of the slumps and the normal faults’ activity, which produced a displacement of up to 30 cm, a new event was characterized in the region. The completely studied block probably rotated to the west and thus the instability of the sediments produced a giant slide, up to 7 m thick and with movement up to 0.9 m, cutting the pre-existing normal faults. The knowledge of the regional evolution, with extensional tectonics during the Jurassic to early Miocene periods, which was inverted to a compressional regime during the middle Miocene, as well as the presence of a major normal fault along the studied section with an NNW–SSE direction, suggested that the studied section was situated on the hanging wall of the above fault during the extensional regime.

Richard S. White

Corrigendum

V. V. Suntsov

It is known that the psychrophilic pseudotuberculosis microbe serotype 1 (Y. pseudotuberculosis 0:1b) causing Far East scarlet-like fever (FESLF) an intestinal infection found in a wide range of invertebrates and vertebrates inhabiting cold regions in the Northern and Central Asia as well as Far East is direct ancestor of the plague causative agent Yersinia pestis. However, the mechanism of Y. pestis speciation remains poorly elucidated. Numerous Y. pestis phylogenies created by using molecular genetic (MG) technologies are largely contradictory, being not in line with reliable data obtained by natural science approaches (e.g., ecology, epizootology, biogeography, and paleontology), which disagree with current evolutionary doctrine (synthetic theory of evolution). The MG approach provides no definitive answer to the questions of where, when, how, and under what circumstances the species Y. pestis arose. One of the reasons for such situation might be due to inadequacy of using the molecular evolutionary model for Y. pestis phylogenetics. Knowledge of the life cycles for the ancestral pseudotuberculosis and derivative plague microbes as well as related unique environmental features allows to create a reliable ecological model for the plague microbe evolution to be further used for assessing patterns of molecular variability and building proper molecular model that might be accepted for MG-reconstruction of plague microbe history. According to the ecological model, the species Y. pestis was formed in a tritopic manner (almost) simultaneously from FESLF clones (populations) in the three geographical populations of the Mongolian marmot-tarbagan (Marmota sibirica) and the flea Oropsylla silantiewi parasitizing on it. The inducer of speciation was coupled to the last maximum (Sartan) cooling in Central Asia occurred 2215 thousand years ago. Soil cooling and deep freezing resulted in altered behavior of the marmot flea larvae with emergence of facultative hematophagy, which, in turn, led to a unique traumatic (compared to routine alimentary) infection route of sleeping marmots with FESLF and, as a result, a unique way of Y. pestis speciation. The molecular model should predict a Y. pestis peripatric tritope speciation, existing numerous parallelisms in intraspecific variability associated with tritope speciation, and the quantum principle of speciation in the highly variable heterothermic (heteroimmune) stressful marmot-flea (Marmota sibirica Oropsylla silantiewi) host-vector environment involving stress-induced mutagenesis. Such molecular model of evolution may be useful for improving molecular methodology of phylogenetic constructions for a wide range of parasitic microorganisms.

Xuefang Wei, Rodrigo Vargas Pêgas, Caizhi Shen et al.

Anurognathids are an elusive group of diminutive, potentially arboreal pterosaurs. Even though their monophyly has been well-supported, their intrarelationships have been obscure, and their phylogenetic placement even more. In the present work, we present a new genus and species from the Middle-Late Jurassic Tiaojishan Formation, the third nominal anurognathid species from the Jurassic of China. The new species provides new information concerning morphological diversity for the group. Furthermore, we provide a new phylogenetic analysis incorporating into a single data set characters from diverging phylogenetic proposals. Our results place them as the sister-group of Darwinoptera + Pterodactyloidea, as basal members of the Monofenestrata.

BRADLEY MCFEETERS, DAVID C. EVANS, HILLARY C. MADDIN

Five new partial skulls of the hadrosaurid dinosaur Maiasaura peeblesorum from the Linster Quarry bone bed (Two Medicine Formation, Campanian) in Montana, USA, provide the basis for a description of the skull roof and braincase morphology of this taxon. These skulls additionally form an ontogenetic series consisting of one subadult, two small “intermediate adults”, and two larger “mature adults”. The subadult skull is approximately two thirds as wide as the largest adult and lacks a nasofrontal crest, suggesting that the crest formed relatively late in ontogeny compared to some other hadrosaurids. As in closely related taxa, larger skulls of M. peeblesorum have a proportionately wider braincase and a larger, more rugosely ridged nasofrontal contact for supporting a larger crest. In the two largest adults, the skull roof incipiently overhangs the anterior margin of the dorsotemporal fenestrae. In the largest skull examined, the crest is semicircular in anterior view and incorporates flared, anteriorly concave prefrontals in its lateral margins. Intraspecific variation in M. peeblesorum is observed in cranial characters previously discussed as interspecific variation in related taxa, including the prominence of dorsal depressions on the frontal, and the position of the foramen for the facial nerve (CN VII). Although cranial ontogeny in Maiasaura shares some trends with Brachylophosaurus and Probrachylophosaurus, it deviates in other ways from the previous heterochronic model proposed for the evolution of Maiasaurini.

Alexander P. Minaev, Nikita I. Iudin

The purpose of the work is to combine all stone Muslim gravestones of the 14th century found during the excavations of the Golden Horde city of Azak. A significant number of publications covers studies of urban and rural necropolises of the Golden Horde cities, including Azak. The publications, in addition to the description of the funerary rite, contain details of the graveside structures. However, the studies are mainly focused on the description of epigraphic inscriptions on gravestones. Their architectural design often falls out of the researchers’ field of interest. In this work, attention is paid to both the epigraphy and the stylistic features of gravestone design. As noted by the authors, the design of Azak gravestones clearly traces the influence of Asia Minor region’s traditions of the Seljuk period. But unlike the finds from Turkey, the gravestones of Azak and the Crimean cities are less ornamented and schematically decorated. The study of stone monuments, including gravestones, allowes to identify the cultural, economic and religious processes that took place in Azak, as well as to determine the origins of certain artistic traditions of different regions of the Golden Horde.

B. GALBIATI, M. OXILIA

The Borghetto d' Arroscia sequence begins with a little known basel post, followed by two lithostratigraphic Units: the M. Bignone Quartzites (Paleocene ? —Eocene ? ) and the Ubaga Limestones (Eocene). Three deformation phases affected the tectonic evolution of the Borghetto d'Arroscia element. They are shown by the minor structures (at outcrop scale) and by the major ones, surveyed at 1/10.000 scale. The first two phases are vergent outwards. The former (Fl ) is characterized by southvergent recumbent folds, the latter (Fl b) gives cut planes slightly dipping, forming the overthrust surface to the same direction. The third phase (F2) is retrovergent and does not change the general structural setting already reached.

ANNE BOERSMA , ISABELLA PREMOLI SILVA

Biserial heterohelicid foraminifera are paleohydrographic indices for open ocean oxygen minimum zones. Comparison of the depletion of biserial heterohelicid carbon isotope ratios with the carbon isotope contrast through the water column is used to describe the strength of Eocene oxygen minima. Combining stable isotope values and percentages of planktonic foraminiferal index species, we describe the following boundary condition for early, middle and latest Eocene oxygen minimum zones in the Atlantic Ocean. Early Eocene - low meridional and vertical thermal contrasts, reduced upwelling and circulation vigor in a moderately war m, stable thermospheric ocean accompany a poorly developed, spatially restricted oxygen minimum. Middle Eocene - invigorated upwelling, large vertical and spatial thermal contrasts caused by cooling at the bottom but not at the surface together with increased ventilation of the water column accompany a strong, widely developed oxygen minimum; and Late Eocene - in a psychrospheric ocean low meridional and vertical thermal contrasts, reduced equatorial upwelling and atmospheric circulation with decreased current circulation vigor correlate with a homogeneous mixed layer in which an oxygen minimum is poorly developed above the thermocline, but not at mid depths.

Daniel Vidal, Pedro Mocho, Adrián Páramo et al.

The functional morphology of sauropod dinosaur long necks has been studied extensively, with virtual approaches yielding results that are difficult to obtain with actual fossils, due to their extreme fragility and size. However, analyses on virtual fossils have been questioned on several of their premises, such as the ability to accurately reconstruct intervertebral tissue with only skeletal data; or whether zygapophyseal overlap can be used to determine the limits of range of motion, since some extreme neck poses in extant giraffes have been claimed not to retain any zygapophyseal overlap. We compared articulation and range of motion in extant giraffes with the exceptionally well-preserved and complete basally branching eusauropod Spinophorosaurus nigerensis from the Middle (?) Jurassic of Niger, under the same virtual paleontology protocols. We examined the articulation and range of motion on grown and young specimens of both Spinophorosaurus and giraffes in order to record any potential changes during ontogeny. Also, the postures of virtual giraffes were compared with previously published data from living animals in the wild. Our analyses show that: (i) articulation of virtual bones in osteologically neutral pose (ONP) does enable accurate prediction of the amount of inter-vertebral space in giraffes and, roughly, in Spinophorosaurus; (ii) even the most extreme neck postures attained by living giraffes in the wild do not require to disarticulate cervical vertebrae; (iii) both living giraffes and Spinophorosaurus have large intervertebral spaces between their cervical centra in early ontogenetical stages, which decrease as ontogeny advances; and (iv) that grown specimens have a greater osteological range of motion in living giraffes and Spinophorosaurus.

Yafit Kedar, Ran Barkai

Hearths were constructed and used at Paleolithic cave and rockshelter sites in Africa, Europe and Asia as early as the late Lower Paleolithic period. The advantages of the use of fire have been widely researched for the last decades. However, only a few studies have focused on the possible negative impact of the use of fire within closed spaces, such as caves. One of the major negative fire products is smoke, which has an immediate, as well as long-term, effect on humans and may even prevent cave occupation after a short period. In this study we propose a basic air circulation model based on thermodynamics to represent smoke ventilation in caves. We employ this model to shed light on the relationship between smoke dispersal and cave structure, opening dimensions, hearth characteristics, and seasonal temperature fluctuations. We further show that hearth location was crucial in allowing humans to occupy prehistoric caves while using fire on a regular basis. We present preliminary insights from specific case studies, demonstrating the potential of understanding smoke ventilation in reconstructing the hearth season of use and location within the cave.

HELMUT FLUEGEL, ANDREA TINTORI

Rugosa and Tabulata from the Late Devonian of central Dolpo (Nepal) belong to the genera Kuangxiastraea, Scruttonia, Sinodisphyllum, Tabulophyllum (?), Fruehwirthia gen. n., Thamnopora, Cladopora, Alveolites and Alveolitella. The calcarenitic beds yielding the fossils are overlain by a prominent oolitic ironstone with thick ferruginous nodules and crusts. The age of the corals is probably Early Frasnian, thus younger than the Givetian fauna previously reported from eastern Dolpo. Biogeographic relations of the new fauna are with Western Europe and South China.

Maximilian Kmenta, Katharina Bastl, Uwe Berger et al.

Abstract Background Grasses release the most widespread aeroallergens with considerable sensitization rates, while different species produce several pollen concentration peaks throughout the season. This study analyzed the prevalence of grass species in three different European city areas and compared the flowering period of these species with daily pollen concentrations and the symptom loads of grass pollen allergy sufferers. Methods The most prevalent grass species in Vienna (Austria), Berlin (Germany) and Turku (Finland) were studied and examined by use of three different approaches: phenology, pollen monitoring and symptom load evaluation. A mobile pollen exposure chamber was employed to observe reaction patterns of grass pollen allergy sufferers to three common grass species evaluated in this study versus placebo. Results Common meadow grass (Poa pratensis) and the fescue grass species (Festuca spp.) are important contributors within the grass pollen season. The pollination period of orchard grass (Dactylis glomerata) and false-oat grass (Arrhenatherum elatius) indicated a greater importance in Berlin and Vienna, whereas a broader spectrum of grass species contributed in Turku to the main pollen season. The standardized provocation induced a nasal symptom load, reduction in nasal flow and increased secretion, in contrary to the placebo control group in grass pollen allergic subjects. Conclusion The phenological observations, pollen measurements and symptom data evaluation provided unique insights into the contribution of multiple grass species in different European regions. All investigated grass species in the provocation induced rhinitis symptoms of comparable significance, with some degree of variation in symptom patterns.

IRINA A. KORETSKY, SULMAN J. RAHMAT

Several excavations in Slovakia resulted in the finding and description of a new species of the extinct phocid subfamily Devinophocinae from the early Badenian, early Middle Miocene (16.26-14.89 Ma). Material of Devinophoca , including the skull, mandibles and teeth, presents distinguishing characters of the subfamily as well as mixed characters with the three extant phocid subfamilies (Cystophorinae, Monachinae and Phocinae). Detailed descriptions of dentition reveal that true seals ranging from 16 million years ago to the present have a generally uniform dental formula within each subfamily, based on total number of incisors: Phocinae (10 incisors; 3/2), Cystophorinae (6 incisors; 2/1); Monachinae (8 incisors; 2/2), and Devinophocinae (also 8 incisors as Monachinae, but in different combination: 3/1). The newly described Devinophoca emryi is represented by the second known skull of this subfamily, with D . claytoni being the first. Certain derived characters in pinnipeds were clearly noticeable on this skull, supporting the phylogenetic analysis that showed D . claytoni as its sister taxon. Stratigraphical examinations suggest that these Paratethyan seals ( D . claytoni and D . emryi )from the Vienna Basin, specifically from the Dev√≠nska Nov√° Ves-Bonanza locality, occupied shallow marine water with coral-reef zones. Over time, they transitioned from a humid, tropical shallow shore zone in the early Badenian (16.26 ‚Äì 14.89 Ma) to a subtropical climate in the middle Badenian (14.89 -13.82 Ma) and a warm temperate climate during the late Badenian (13.82 -12.73Ma).

CRISTIANO DAL SASSO, GIANNI INSACCO, ALFIO ALESSANDRO CHIARENZA et al.

Here we report for the first time on the presence of ichthyosaurs in Sicily, southern Italy. The deposit of origin (Mufara Formation) can be dated to the upper Carnian (Tuvalian substage) based on a typical association of ammonites, one of which (Shastites sp.) is embedded in the sediment still encrusting one of the bone specimens recently found. The latter consist of two isolated vertebral centra that are referred to the Ichthyosauria thanks to their disk-like shape (i.e. they are much taller than long) combined with the amphicelous condition, lack of transverse processes, and presence of rib articulations on the central sides. The largest specimen is more precisely an anterior dorsal vertebra from an adult individual, ascribed to Shastasauridae indet. By the presence of elongated reniform diapophyseal facets, cranially not truncated, and absence of parapophyses. The smaller specimen represents an anterior cervical element from an immature individual of a likely smaller-sized, indeterminate taxon. These finds indicate that the biodiversity of the Monte Scalpello Triassic fauna is higher than previously known, but above all represent the southernmost occurrence of Triassic ichthyosaurs in the western Tethys basin.

Felipe Pimentel Lopes de Melo, Victor Arroyo-Rodríguez, Bráulio Almeida Santos et al.

In this essay we examine some of the processes affecting the composition and structure of tree species assemblages and, consequently, what we can expect from secondary-forest stands as an element of human-modified landscapes and as an opportunity for biodiversity persistence in this ecological context. Based on the available information, it is reasonable to predict that in some landscapes or biotas: (1) small forest remnants degenerate and support plant assemblages with attributes similar to those observed in early and intermediate-aged regenerating stands, while secondary-forest stands move from initial to more advanced successional stages; (2) collectively, remnant/stand attributes and landscape integrity define the pace through which degeneration proceeds, but also the potential for regeneration; (3) at the landscape spatial scale, remnants and stands tend to converge in terms of structure, but also in terms of taxonomic and functional composition. In other words, remnants degenerate and secondary-forest stands regenerate toward a sort of ‘climax community’, which is conditioned by the physical and biological integrity of both patch and landscape. Considering secondary forests in the conceptual, ecological and spatial framework of human-modified landscapes may help us to understand and maximize the conservation services provided by this habitat as it proliferates through human-modified landscapes.

A. Romer

W. P. Woodring, M. Bramlette, W. Kew

E. C. Galbreath