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The Ediacaran-Cambrian transition is marked by the diversification of metazoans in the marine realm. However, this is not recorded by the Ediacaran-Cambrian Bambuí Group of the São Francisco basin, Brazil. Containing the sedimentary record of a partially confined foreland basin system, the Bambuí strata bear rare metazoan remnants and a major carbon isotope positive excursion decoupled from the global record. This has been explained by changes in the paleogeography of the basin, which became a restricted epicontinental sea in the core of the Gondwana supercontinent, promoting episodes of shallow water anoxia. Here, we report new δ15Nbulk data from the two lowermost second-order transgressive-regressive sequences of the Bambuí Group. The results show a rise of δ15N values from +2 to +5‰ in the transgressive system tract of the basal sequence, which was deposited when the basin was connected to other marginal seas. Such excursion is interpreted as an oxygenation event in the Bambuí sea. Above, in the regressive systems tract, δ15N values vary from +2 to +5‰, pointing to instabilities in the N-cyle that are concomitant with the onset of basin restrictions, higher sedimentary supply/accommodation ratios, and the episodic anoxia. In the transgressive systems tract, the δ15N values stabilise at ∼+3.5‰, pointing to the establishment of an appreciable nitrate pool in shallow waters in spite of the basin full restriction as marked by the onset of a positive carbon isotope excursion. In sum, our data show that the N-cycle and its fluctuations were associated with variations in sedimentary supply/accommodation ratios induced by tectonically-related paleogeographic changes. The instability of the N-cycle and redox conditions plus the scarcity of nitrate along regression episodes might have hindered the development of early benthic metazoans within the Bambuí seawater and probably within other epicontinental seas during the late Ediacaran-Cambrian transition.

This paper shows the preliminary results of the zooarchaeological analysis of Dupuy Rockshelter (La Toma, San Luis Province, Argentina). This rock shelter has evidence of Late Holocene (Last Millennium) human occupation dating from 340 ± 40 BP. Some species, including Lama guanicoe and Ozotoceros bezoarticus , were exploited and their bones were used as raw material to make instruments. The zooarchaeological analysis is complemented by geological and phytoarchaological evidence which indicates a humid environment during the Holocene and a mixed diet that included vegetables. [ABSTRACT FROM AUTHOR]

Functional traits of herbivorous mammals provide tools for reconstructing past environments. In 1952, Björn Kurtén used distribution of ecomorphological features in fossil herbivorous mammal communities from Late Miocene "Hipparion faunas" of Eurasia to characterize their paleoenvironments as "steppe", "forest" and "mixed" types. We tested Kurtén's results with a revised set of ecometric methods. We used dental ecometric estimates of mean annual temperature and precipitation, net primary productivity, and normalized difference vegetation index to compare Miocene localities with modern biomes, and dental mesowear to estimate woody and grass cover in the paleoenvironments. Our results agree with Kurtén's, indicating steppe-edge environments in northern China, wooded paleoenvironments in Pikermi, Greece, and central Europe, and open woodland-grassland environment in Maragheh, Iran. Our analyses indicate the presence of wooded grassland savanna in Lothagam and tropical forest in Lukeino in East Africa, further demonstrating paleoenvironmental variation and ecological diversity within later Late Miocene "Hipparion faunas". [ABSTRACT FROM AUTHOR]

The palynofacies and sedimentological analyses of the sedimentary succession of the HB-001 well were carried out to establish biozones and the palaeodepositional environment. Ninety-six samples of ditch cutting within intervals of depth of 1250 -4011 m were analyzed. Most of the previous researchers established biozones with alpha-numeric method. The use of palynomorphs and palynofacies analyses to delineate paleoenvironment of deposition has been applied to a limited extent in the Niger Delta Basin in Nigeria. The analysis produced fairly diverse and moderately abundant pollen and spores with high recoveries of palynomaceral 1 and 2 and minimal retrievals of palynomaceral 3 and 4. The textural, lithologic, as well as wireline log data point out that the whole studied interval in the HB-001 well fit in to the Agbada Formation. Late Miocene age was assigned on the bases of the analysis of stratigraphic age range of indicative palynological markers for example Zonocostites ramonae, Verrucatosporites sp., Laevigatosporites sp., Monoporites annulatus, Pachydermites diederixi and Psila, tricolporites crassus. Two assemblage zones were established in the well with the use of the International Stratigraphic Guide for the biozones establishment. The two recognized palynostratigraphic zones are Cyperaceaepollis sp. - Nympheaepollis clarus, and Stereisporites sp Zones. Lower delta plain, pro-delta and delta front depositional environments have been deciphered for well with the use of the palynofacies association, palyno-ecological groupings, and sedimentological features. Bodies of sand that signify sub-environments inside these settings are deposited in sequences. Every sequence begins with a transgressive stage, after that considerable regression. The palyno-ecological groupings of the retrieved palynomorph taxa revealed that the well intervals studied were deposited under alternating wet and dry paleoclimatic settings. The zones of dry climate presented high account of montane and savannah taxa and low incidence of rainforest, mangrove and freshwater taxa. The zones of wet climate signified increased account of rainforest, freshwater and mangrove taxa and lower incidences of montane and savannah taxa. [ABSTRACT FROM AUTHOR]

Copyright of Ameghiniana is the property of Argentine Paleontological Association / Asociacion Paleontologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The study of the chondrichthyan fauna from the Angostura, Onzole, Canoa and Jama formations, in the Neogene of Bordón and Manabí basins, Ecuador, reveals the presence of 30 taxa, including the deep water shark †Chlamydoselachus landinii sp. nov. The assemblages are dominated by tropical shallow and deep water chondrichthyans, suggesting paleoenvironments associated with a short platform shelf bordering a deep margin. These assemblages are the most diverse shark and ray association known from the Tropical Central Eastern Pacific Ocean in the South American coastal basin, and provide new information on the paleoecology and paleodiversity of Neogene chondrichthyans. [Copyright &y& Elsevier]

The Late Pleistocene littoral ridges of southern South America, especially those of the north of Argentinean Patagonia, contain remains of mollusk shells with bioerosion traces. Eleven sites from marine isotope stages (2 from MIS 7, 4 from MIS 5e) and five sites from modern beaches from northern Río Negro Province, with 40 taxa (17 bivalves and 23 gastropods) were analyzed, in the area between west of Baliza San Matías and Las Grutas (41°S). Three ichnogenera were identified in deposits of MIS 7: Entobia, Gastrochaenolites (Domichnia) and Oichnus (Praedichnia) with one ichnospecies (G. torpedo). Six ichnogenera were identified in deposits of MIS 5e: Entobia, Meandropolydora, Pinaceocladichnus, Iramena, Caulostrepsis and Oichnus with one ichnospecies (O. simplex). Seven ichnogenera were identified from modern beaches: Entobia, Meandropolydora, Iramena, Caulostrepsis, Pinaceocladichnus, Gastrochaenolites (Domichnia) and Oichnus (Praedicnia), with two ichnospecies (O. simplex and O. paraboloides). On this basis, it is inferred that Pleistocene benthic communities were constituted from cheilostome bryzoans and polychaete annelids, together with drilling bivalves, predatory gastropods and overall warm‐water species of mollusks. Of these, Chama iudicai was found on Plicatula gibbosa from MIS 7 and MIS 5e. The record of warm temperature species suggests a higher sea surface temperature (SST) than the present one and/or the influence of the warm southward Brazilian Current affecting the waters of Golfo San Matías. On the modern beaches surveyed, there is an increase in polychaete annelids, cheilostome bryzoans, temperate‐cold species and drilling bivalves, as well as sandy substrate species, which together with an increase of Gastrochaenolites and Caulostrepsis, suggest a colder climate due to the greater influence of the Malvinas Current during the Holocene. [ABSTRACT FROM AUTHOR]

Postcranial elements (cervical, sacral and caudal vertebrae, as well as ilium, rib and limb bone fragments) belonging to a gigantic tetanuran theropod were recovered from the basal unit (the White Rock Sandstone equivalent) of the Vectis Formation near Compton Chine, on the southwest coast of the Isle of Wight. These remains appear to pertain to the same individual, with enormous dimensions similar to those of the Spinosaurus holotype and exceeding those of the largest European theropods previously reported. A combination of features--including the presence of spinodiapophyseal webbing on an anterior caudal vertebra--suggest that this is a member of Spinosauridae, though a lack of convincing autapomorphies precludes the identification of a new taxon. Phylogenetic analysis supports spinosaurid affinities but we were unable to determine a more precise position within the clade weak support for a position within Spinosaurinae or an early-diverging position within Spinosauridae were found in some data runs. Bioerosion in the form of curved tubes is evident on several pieces, potentially related to harvesting behaviour by coleopteran bioeroders. This is the first spinosaurid reported from the Vectis Formation and the youngest British material referred to the clade. This Vectis Formation spinosaurid is unusual in that the majority of dinosaurs from the Lower Cretaceous units of the Wealden Supergroup are from the fluviolacustrine deposits of the underlying Barremian Wessex Formation. In contrast, the lagoonal facies of the upper Barremian--lower Aptian Vectis Formation only rarely yield dinosaur material. Our conclusions are in keeping with previous studies that emphasise western Europe as a pivotal region within spinosaurid origination and diversification. [ABSTRACT FROM AUTHOR]

In order to study the lithostratigraphy, biostratigraphy, microfacies, depositional setting and also to reconstruct the paleo-environmental conditions of the Tirgan Formation, three outcrop sections were selected in the western part of the Kopet-Daghh sedimentary basin. These sections locate at the Estarkhi village (30 km East of Shirvan city), the Jozak (40 km West of Bojnourd city) and the Zaw Mountain (45 km far from the Kalaleh city). Geographical coordinates of these outcrop sections are: 57o, 51', 31" longitude and 37o, 11', 29" latitude in Estrakhi section, 56o, 42', 25" longitude and 37o, 24', 55.8" latitude in Jozak section, and finally, 55o, 45', 10.6" longitude and 37o, 31', 20" latitude in Zaw section. The Tirgan Formation has a thickness of 129 m in Estarkhi, 362 m in Jozak and 639 m in Zaw section, in which measured and samples to be used in this study. A total number of 62, 102 and 226 rock samples was taken respectively from the Estarkhi, Jozak and Zaw sections, and used for the microscopic studies. Therefore, a total number of 700 thin-sections were prepared from the rock samples and studied under the microscope. In Estarkhi section, the Shurijeh Formation is overlain conformably by the Tirgan Formation. Moreover, the upper contact of the Tirgan Formation with the upper rock unit, the Sarcheshmeh Formation, is continues and conformable. In this outcrop section, the Tirgan Formation begins with siliciclastic deposits with intercalations of marls, representing a gradational passage from the continental Shurijeh Formation to the marine deposits of the Tirgan Formation. The Jozak section represents a conformable and continues contact between the Tirgan Formation with the underlying Shurijeh Formation, but, its upper contact with the overlying Abderaz Formation is cut by a fault. In Zaw section, the lower contact of the Tirgan Formation with the Zard Formation is continues and conformable, but, its upper contact with the younger deposits is covered and unclear. Based on the distribution of facies belts, three paleogeographical maps were prepared for the study area. They are: Hauterivian-lower Barremian, lower Barremian-upper Barremian and upper Barremian-lower Aptian. Analysis of these maps shows that during the Hauterivian-lower Barremian, in the far eastern part of the study are (e.g. Estarkhi section), the Tirgan Formation includes in siliciclastic deposits with some marine marls, in that the detrital sediments was carried to the foreland basin as a result of erosion of high structures. In the same time, the western parts of the study area was covered by deposits belonging to a tidal-flat depositional setting, representing a deepening trend from the East towards the West of the area. During the Barremian (lower Barremian-upper Barremian), a major deepening trend has occurred for the both vertical and horizontal extend regionally in the study area. Therefore, the Estarkhi area was covered by tidalflat deposits, and in the same time, the deepening trend was continued towards the west, led to the deposition of shoal and open marine facies in the Jozak and Zaw area. Finally, in the upper Barremian-lower Aptian, a stable condition was govern for the entire area, led to the deposition of orbitolina bearing limestones totally in the study area. Vertical distribution of facies belts shows that the eastern part of the study area (e.g. Estarkhi section), represents a major deepening upward trend during the upper Barremian-lower Aptian, which is comparable with general and global transgressive trends for the Barremian-Aptian interval. But, in the western part (e.g. Jozak and Zaw areas), the bathymetry was often stable, and somehow, shows a shallowing trend, that probably belongs to the role of basement faults and local tectonic activities, creating various accommodation space on the shallow platform setting in this part of the Kopet- Daghh Basin. [ABSTRACT FROM AUTHOR]

Featured Application: A challenging issue for humankind is the understanding of the future biota state within the context of global change (anthropogenic CO2 emissions, global warming, ocean acidification, eutrophication, anoxia). Studies on modern biomaterials reveal that the climate-induced environmental stress is affecting the stability of ecosystems. However, modern analyses are limited to decades/historical times whereas the paleontological record can reconstruct the impact of past global climate analogues on a thousand/hundreds/million-year perspective. This work fits the goal to deciphering how marine calcareous nannofossils, benthic and planktic foraminifera, unicellular algae and protozoan, reacted to the global warming known as Middle Eocene Climatic Optimum (MECO), centered at ~40 Ma ago and lasting ~500–600 kyr. Our detailed integrated reconstruction from the Neo-Tethyan geological setting (eastern Turkey) with thousand years' resolution (~100 m/My) reveals that the MECO warming peak induced marked water eutrophication, reduction in oxygen availability at the sea floor and carbonate dissolution. Part of the analyzed marine biota proved to be resilient to the MECO perturbation through marked modifications within assemblages whereas the most specialized planktic foraminifera declined permanently their abundance permanently. Biota and environment only partially recovered the pre-event conditions after the MECO warming peak. Our study, recording transient and permanent changes, allows to understand how paleoenvironment and marine biota reacted to the global MECO perturbation. The Middle Eocene Climatic Optimum (MECO; ~40 Ma), which interrupted for ~500–600 kyr the long-term cooling trend culminating at the Eocene/Oligocene boundary, still requires a comprehensive understanding of the biotic resilience. Here we present a high-resolution integrated foraminiferal and calcareous nannofossil study across the MECO from the expanded and continuous Tethyan Baskil section (eastern Turkey) that offers a complete magneto-biostratigraphic and geochemical framework. The five MECO phases identified reveal a transition from oligotrophic (pre-MECO) to eu-mesotrophic conditions, possibly related to accelerated hydrological cycle, during the initial MECO and MECO δ13C negative excursion phases. The MECO WARMING PEAK phase, marking the highest carbonate dissolution interval, records the most striking biotic changes, such as peak in warm and eutrophic nannofossils, virtual disappearance of the oligotrophic planktic foraminiferal large Acarinina and Morozovelloides, and peak in eutrophic deep dwellers Subbotina. Benthic foraminifera suggest in this phase an improvement in the quality of organic matter to the seafloor. The post-MECO phase shows only a partial recovery of the pre-event conditions. Large Acarinina and Morozovelloides did not recover their abundance, possibly due to cooler conditions in this phase. Our reconstruction reveals how paleoenvironment and marine biota from the studied Neo-Tethyan setting reacted to the MECO perturbations. [ABSTRACT FROM AUTHOR]

A new fossil batoid (ray) Ptychotrygon rostrispatula sp. nov. is described from five exceptionally well‐preserved, three‐dimensional skeletal remains from the Turonian (Late Cretaceous) of Morocco. These specimens represent the first known skeletal remains for the genus Ptychotrygon and allow an almost complete description of the genus, providing a new insight into its phylogenetic relations and validating its taxonomic status as a member of the Sclerorhynchoidei. Mechanical preparation of the fossil remains revealed a relatively large batoid species (estimated total length above 1 m). Overall the morphology resembles that of sclerorhynchoids, with a robust hypertrophied rostrum that lacks enlarged rostral denticles with enlarged paddle‐like pectoral proximal elements (propterygium, mesopterygium and metapterygium). Never before seen details of the branchial skeleton are presented (large second hypobranchial without anterior process, which was probably fused to the basibranchial and no evidence of articulation with other branchial element). To assess the phylogenetic relations of these specimens within the sclerorhynchoids a parsimonious analysis using TNT and PAUP was performed. These analyses included Asflapristis cristadentis and Ptychotrygon rostrispatula sp. nov., which were used as representatives of Ptychotrygonidae, and also includes six other genera of sclerorhynchoids with relatively good skeletal remains. Both analyses recovered two monophyletic groups within sclerorhynchoids: the first contains Ischyrhiza, Onchopristis and Schizorhiza, and a second that includes Micropristis, Sclerorhynchus, Libanopristis and Ptychotrygonidae. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Megalospheric specimens of Nummulitidae from eight localities in western and central Cuba were morphometrically investigated using test characters described by 11 growth-independent and growth-invariant attributes that provide a complete geometric reconstruction of nummulitid equatorial morphology. The species Nummulites striatoreticulatus, Palaeonummulites trinitatensis, Operculinoides floridensis and O. soldadensis were classified by an agglomerative cluster analysis. Discriminant analysis yielded significant morphological separators between the species such as the backbend angle, marginal radius increase, perimeter ratio and first chamber length. The transition of tightness to laxity of the spiral was an important morphological separator at the generic level, representing a clear general trend coupled with the change in palaeodepth. Based on further discriminant analysis, an increase in proloculus size was detected in Nummulites striatoreticulatus from the middle Eocene to early late Eocene, supporting this important evolutionary pattern in many lineages of Nummulites. Operculinid forms showed an opposite and more weakly pronounced time-dependent trend in the size decrease of the proloculus. In the Cuban localities, Nummulites striatoreticulatus occurs from the Lutetian to Priabonian, while Palaeonummulites trinitatensis is restricted to the Bartonian to Priabonian. The moderately to loosely coiled operculinid taxa O. floridensis and O. soldadensis have longer stratigraphical ranges from the middle Eocene to probably the early Oligocene. Operculinoides floridensis and O. soldadensis show a broader variability in marginal radius increase, and thus probably occupied wider niches than N. striatoreticulatus. The latter seems to be restricted to the shelf edge and to the shallowest parts of the upper slope. A possible phylogenetic connection between Heterostegina and Operculinoides is suggested by the closest equatorial morphology of Heterostegina sp. indet. to tightly coiled forms of Operculinoides floridensis. Discriminant analysis documents the strongest similarities in perimeter ratio, backbend angle, initial marginal radius and proloculus mean diameter. [ABSTRACT FROM AUTHOR]

Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by the IPCC for this century, assuming unabated CO2 emissions. Sediments recovered by the Integrated Ocean Drilling Program (IODP) at Site U1356, offshore of the Wilkes Land margin in East Antarctica, provide an opportunity to study ice sheet and paleoceanographic configurations during the late Oligocene (26-25 Ma). Our study, based on a combination of sediment facies analysis, magnetic susceptibility, density, and X-ray fluorescence geochemical data, shows that glacial and interglacial sediments are continuously reworked by bottom currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted as resulting from a northward shift of westerly winds and surface oceanic fronts. Interglacial sediments record more oxygenated and ventilated bottom water conditions and strong current velocities, which suggests enhanced mixing of the water masses as a result of a southward shift of the polar front. Intervals with preserved carbonated nannofossils within some of the interglacial facies are interpreted as forming under warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g., North Atlantic sourced deep water) had a greater influence on the site. Spectral analysis on the late Oligocene sediment interval shows that the glacial-interglacial cyclicity and related displacements of the Southern Ocean frontal systems between 26 and 25Ma were forced mainly by obliquity. The paucity of iceberg-rafted debris (IRD) throughout the studied interval contrasts with earlier Oligocene and post-Miocene Climate Optimum sections from Site U1356 and with late Oligocene strata from the Ross Sea, which contain IRD and evidence for coastal glaciers and sea ice. These observations, supported by elevated sea surface paleotemperatures, the absence of sea ice, and reconstructions of fossil pollen between 26 and 25 Ma at Site U1356, suggest that open-ocean water conditions prevailed. Combined, this evidence suggests that glaciers or ice caps likely occupied the topographic highs and lowlands of the now marine Wilkes Subglacial Basin (WSB). Unlike today, the continental shelf was not overdeepened and thus ice sheets in the WSB were likely land-based, and marine-based ice sheet expansion was likely limited to coastal regions. [ABSTRACT FROM AUTHOR]

The seasonal changes in the contents and compositions of n-alkanes and n-methyl ketones have been studied in typical soddy-podzolic soils (Albic Retisols (Ochric)) under lime forests in the Losiny Ostrov National Park, Moscow. In the humus horizons, the reserves (about 370 mg/m2) of odd n-alkanes with the chain length of C25-C35—the biomarkers of terrestrial vegetation—are 4-5 times below their amount entering with the leaf falloff in autumn. A noticeable contribution of microbial biomass hydrocarbons to the lipid fraction in the AY and AYel horizons manifests itself in the increased fraction of odd and medium-chain (25) homologues (OEP = 4-6, LSR = 5-7) in the spectrum of n-alkanes. The lowest content of methyl ketones and odd n-alkanes was observed immediately after the winter period (OEP = 22, A/K = 21-170). In the EL and BT horizons, the n-alkane fraction of organic matter and the relative content of high molecularweight n-alkanes more resistant to microbial destruction (C33, C35) increases by 3-4 times in comparison with that in the abovelying horizons, and the type of distribution of n-alkanes by the carbon chain length changes: the dominance of odd homologues is absent; in the EL horizon, OEP = 1. [ABSTRACT FROM AUTHOR]

The late Miocene beds of the Puerto Madryn Formation (Provincia del Chubut, Argentina) are formed by shallow marine and estuarine sediments. The latter include several tidal-channel infills well exposed on the cliffy coast of the Peninsula Valdés. The Bahía Punta Fósil and Cerro Olazábal paleochannels are end members of these tidal channels and show a fining-upward infilling starting with intraformational channel lag conglomerates above deeply erosional surfaces interpreted as fluvial ravinement surfaces (the erosion surface formed in the purely fluvial or the fluvially dominated part of the estuary, where erosion is driven by fluvial processes). These are overlain and eventually truncated (and suppressed) by the tidal ravinement surface (TRS), in turn covered with high-energy, bioclastic conglomerates mostly formed in the 'tidally dominated/fluvially influenced' part of an estuary. Above, large straight or arcuate point bars with alternatively sandy/muddy seasonal beds and varying trace and body fossil contents were deposited from the freshwater fluvially dominated to saline-water tidally dominated part of the estuary. The upper channel infill is formed by cross-bedded sands with mud drapes and seaward-directed paleocurrents, together with barren, volcaniclastic sandy to muddy heterolithic seasonal rhythmites, both deposited in the fluvially dominated part of the estuary. Volcanic ash driven by the rivers after large explosive volcanic eruptions on land resulted in sedimentation rates as high as 0.9 m per year, preserving (through burial) the morphology of tidal channels and TRSs. The channel deposits were formed in a tide-dominated, macrotidal to hypertidal open estuary with well-developed TRSs resulting from strong tidal currents deeply scouring into the transgressive filling of the channels and eventually cutting the fluvial ravinement surface. The TRSs extended upstream to the inner part of the estuary during long periods of low sedimentation rates, extended channel migration and sediment bypass, interrupted by transient, high volcaniclastic input. The tidal channels of the Puerto Madryn Formation constitute a unique example of estuary sedimentation with pulsed sediment supply in a macrotidal to hypertidal estuary. [ABSTRACT FROM AUTHOR]

During the Cretaceous, there were several relatively short intervals with a relatively low oxygen content in the water column. They were named 'Oceanic anoxic events.' These events changed essentially the characteristics of the water masses, which had a significant effect on the morphology of planktonic foraminifers. The proportion of taxa with elongated chambers of the last whorl periodically increased. This structural feature probably provided shells with certain advantage under nonstandard oceanographic conditions. The elongated chambers were probably advantageous for dwelling in conditions of a low oxygen content in the water column. The small size, extended last whorl chambers, and thin and light wall facilitated floating in the upper water layers, which are particularly rich in oxygen. This hypothesis is corroborated by widespread periodic lateral distribution of the morphotypes with extended chambers of the last whorl during rather short intervals with the low oxygen content in sea water, making them an important marker of paleoenvironments. Returning to the normal environmental parameters promoted an increase in the taxonomic diversity of planktonic foraminifers and appearance of new morphological features. At the same time, each of these events had certain distinctive features. [ABSTRACT FROM AUTHOR]

Red Clay underlying the loess-palaeosol sequences on the Chinese Loess Plateau is an eolian deposit. There is a controversy over whether magnetic susceptibility (χ) variations in Red Clay sequence can be used as an indicator of summer palaeomonsoon intensity. This study investigates the magnetic mineralogy, magnetic concentration and magnetic grain size distribution of Jiaxian Red Clay with multimagnetic methods. Our results indicate that the magnetic properties of Jiaxian Red Clay are similar to those of the Quaternary loess-palaeosol sequences, and ultrafine ferrimagnetic grains produced during pedogenesis are responsible for an increase in susceptibility, therefore the χ enhancement mechanism of Red Clay is similar to that of the overlying loess-palaeosol sequences. This paper explores χ variations in the Red Clay sequence through spatial and temporal analysis. The susceptibility variation of six sites along a NNE to SSW transect correlate to palaeoclimatic cycles, so χ can be used to trace the summer palaeomonsoon intensity from a spatial perspective. However, a simple loess-derived calibration function cannot be used to quantitative reconstruct the palaeomonsoon intensity variations thought time. An adjusted calibration function for palaeosols from Red Clay sequence needs to be developed, so that χ can be used to quantitative reconstruct palaeomonsoon intensity. Further study is necessary to develop such a transfer function. [ABSTRACT FROM AUTHOR]

The view of spinosaurs as dinosaurs of semi-aquatic habits and strongly associated with marginal and coastal habitats are deeply rooted in both scientific and popular knowledge, but it was never statistically tested. Inspired by a previous analysis of other dinosaur clades and major paleoenvironmental categories, here we present our own statistical evaluation of the association between coastal and terrestrial paleoenvironments and spinosaurids, along with other two theropod taxa: abelisaurids and carcharodontosaurids. We also included a taphonomic perspective and classified the occurrences in categories related to potential biases in order to better address our interpretations. Our main results can be summarized as follows: 1) the taxon with the largest amount of statistical evidence showing it positively associated to coastal paleoenvironments is Spinosauridae; 2) abelisaurids and carcharodontosaurids had more statistical evidence showing them positively associated with terrestrial paleoenvironments; 3) it is likely that spinosaurids also occupied spatially inland areas in a way somehow comparable at least to carcharodontosaurids; 4) abelisaurids may have been more common than the other two taxa in inland habitats. [ABSTRACT FROM AUTHOR]

The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats. [ABSTRACT FROM AUTHOR]

Experimental archaeology at a Natufian site in the Southern Levant documents for the first time the use of 12,500-year-old rock-cut mortars for producing wild barley flour, some 2,000 to 3,000 years before cereal cultivation. Our reconstruction involved processing wild barley on the prehistoric threshing floor, followed by use of the conical mortars (a common feature in Natufian sites), thereby demonstrating the efficient peeling and milling of hulled grains. This discovery complements nearly 80 years of investigations suggesting that the Natufians regularly harvested almost-ripe wild cereals using sickles hafted with flint blades. Sickles had been replicated in the past and tested in the field for harvesting cereals, thusly obtaining the characteristic sheen along the edge of the hafted flint blades as found in Natufian remnants. Here we report that Natufian wide and narrow conical mortars enabled the processing of wild barley for making the groats and fine flour that provided considerable quantities of nourishment. Dishes in the Early Natufian (15,000–13,500 CalBP) were groat meals and porridge and subsequently, in the Late Natufian (13,500–11,700 CalBP), we suggest that unleavened bread made from fine flour was added. These food preparing techniques widened the dietary breadth of the sedentary Natufian hunter-gatherers, paving the way to the emergence of farming communities, the hallmark of the Neolithic Revolution. [ABSTRACT FROM AUTHOR]

The Gurpi Formation is a well-known source rock in the Zagros basin, which stretches from northeast to southwest Iran. Sequence stratigraphy was done based on the integration of evidence derived from palynological proxies and foraminiferal data. According to sequence stratigraphy, seven time lines including four sequence boundaries of type II and three maximum flooding surfaces with a resolution varying from 1 to 5 MY and three complete third-order sequences and one transgressive systems tract (TST) were differentiated. Maximum flooding surface of the first sequence in middle Campanian probably equates the 70-Ma maximum flooding surface (MFS) K175 of Sharland et al. (GeoArabia P: 371, 2001), and MFS of the second sequence in early Maastrichtian is correlated with the marked 68-Ma MFS (MFS K180) of Sharland et al. (GeoArabia P: 371, 2001) that is recorded in many parts of the Arabian Plate. Correlation with the Haq global eustatic curve, though uncertain because of the effect of local tectonics over the relative sea level changes, however, could be possible with the 69.5 Ma. Also, purple shales of the base of the Pabdeh Formation with a Thanetian age are defined as a MFS, correlation of which with the marked 58-Ma MFS (MFS Pg10) of Sharland et al. (GeoArabia P: 371, 2001) and with 56.5-Ma MFS of Haq seems likely. The relative sea level curve resulted in this study is not well in accord with the existing eustasy curves for the middle Campanian-late Paleocene indicating effect of tectonic on relative sea level changes during this period. [ABSTRACT FROM AUTHOR]

Pseudofurnishius is a late Anisian (Pelsonian)--early Carnian (Cordevolian) conodont genus of gondolellid stock, characteristic for the Sephardic Province and restricted to the "Southern Tethys" region of the northern margin of Gondwana. Its most commonly found species, Pseudofurnishius murcianus, appears at the base of the Ladinian (Fassanian). The Ladinian material of Spain reveals its ontogeny characterised by initial lateral protrusions from the carina that may develop first mono-platform and later bi-platform units, finally evolving into elaborated multi-denticulated forms. The late Anisian-- early Carnian phylogenesis of Pseudofurnishius priscus → P. shagami → P. murcianus is proposed. At the end of the Ladinian, Pseudofurnishius expanded to the entire "Southern Tethys" shelf and into Cimmerian terranes that drifted away from northern Gondwana, now accreted to Eurasia, such as the Sibumasu terrane (Southwest China--Malayan Peninsula). [ABSTRACT FROM AUTHOR]

Tinamous, one of the earliest diverging living avian lineages, consists of a Neotropical clade of palaeognathous birds with a fossil record limited to the early Miocene-Quaternary of southern South America. Here, we conduct a comprehensive, morphology-based phylogenetic study of the interrelationships among extinct and living species of tinamous. Morphological data of fossil species are included in a matrix of 157 osteological and myological characters of 56 terminal taxa. The monophyly of most recognized genera is supported by the results of the analysis. The cladistic analysis also recovers the traditional subdivision between those tinamous specialized for open areas ( Nothurinae) and those inhabiting forested environments ( Tinaminae). Temporal calibration of the resultant phylogeny indicates that such a basal divergence had already taken place in the early Miocene, some 17 million years ago. The placement of the fossil species within the open-area ( Nothurinae) and the forest-dwelling ( Tinaminae) tinamous is also consistent with the palaeoenvironmental conditions inferred from the associated fauna. © 2014 The Linnean Society of London [ABSTRACT FROM AUTHOR]

The paleodepositional system dynamics of the Lockhart Limestone are elucidated in the Western Salt Range with the help of microfacies analysis. Three facies associations are recognised in downslope, along a distally steepened carbonate ramp platform. These facies associations correspond to inner ramp, middle ramp and ramp slope settings. The age-diagnostic foraminiferal species recognized consisted of Miscellanea miscella, Ranikothalia sindensis, Discocyclina ranikotensis, Alveolina vredenburgi and Assilina dandotica. Based on this larger foraminiferal assemblage a Late Thanetian age has been assigned to the Lockhart Limestone. The biostratigraphy implies that ramp carbonates were deposited in a single third order depositional cycles in a high stand systems tract. [ABSTRACT FROM AUTHOR]

The Trachyleberididae is one of the most diverse families of the Ostracoda in Mesozoic to present-day marine environments. Its type genus is Trachyleberis Brady, 1898, first described on the basis of specimens collected alive. Unfortunately the identity and morphological characteristics of the type species of Trachyleberis have long been the subject of confusion resulting from misidentifications and misunderstandings in the literature. We review the taxonomic history of this problem, providing extensive synonymies, new diagnoses, descriptions and illustrations of relevant species. We establish the identity of the type species of Trachyleberis, Cythere scabrocuneata Brady, 1880, by reference to a previously-designated lectotype from the Seto Inland Sea, Japan, noting that a second distinct species, Trachyleberis niitsumai Ishizaki, 1971, is represented in the original syntypic series. We consider that in the interests of nomenclatural and taxonomic stability C. scabrocuneata should be retained as the type species of Trachyleberis, despite the fact that the original description of the genus was based on a species misidentified as C. scabrocuneata and which was subsequently described as a new species, Trachyleberis lytteltonensis Harding and Sylvester-Bradley, 1953. The geographical and stratigraphical distributions of Trachyleberis are reconsidered in the light of our revision. Trachyleberis now comprises 18 known species inhabiting shallow marine environments of the Northwestern Pacific from Japan to the northern coast of the South China Sea off Hong Kong. The revised stratigraphic occurrence of Trachyleberis is from the Eocene to Recent. As many as 400 living and fossil species have been previously assigned to Trachyleberis and they range from the Cretaceous to the Recent; Cretaceous species formerly attributed to Trachyleberis are now re-assigned to other genera. We suggest that Trachyleberis most likely evolved from a Cythereis-like ancestor during the Eocene-Oligocene of Japan, the same area that is the centre of its modern distribution. [ABSTRACT FROM AUTHOR]

Pleistocene climate fluctuations have shaped the patterns of genetic diversity observed in extant species. Although the effects of recent glacial cycles on genetic diversity have been well studied on species in Europe and North America, genetic legacy of species in the Pleistocene in north and northwest of China where glaciations was not synchronous with the ice sheet development in the Northern Hemisphere or or had little or no ice cover during the glaciations' period, remains poorly understood. Here we used phylogeographic methods to investigate the genetic structure and population history of the chukar partridge Alectoris chukar in north and northwest China. A 1,152 - 1,154 bp portion of the mtDNA CR were sequenced for all 279 specimens and a total number of 91 haplotypes were defined by 113 variable sites. High levels of gene flow were found and gene flow estimates were greater than 1 for most population pairs in our study. The AMOVA analysis showed that 81% and 16% of the total genetic variability was found within populations and among populations within groups, respectively. The demographic history of chukar was examined using neutrality tests and mismatch distribution analyses and results indicated Late Pleistocene population expansion. Results revealed that most populations of chukar experienced population expansion during 0.027 - 0.06 Ma. These results are at odds with the results found in Europe and North America, where population expansions occurred after Last Glacial Maximum (LGM, 0.023 to 0.018 Ma). Our results are not consistent with the results from avian species of Tibetan Plateau, either, where species experienced population expansion following the retreat of the extensive glaciation period (0.5 to 0.175 Ma). [ABSTRACT FROM AUTHOR]

An automated layer counting technique is developed to estimate the chronology of a marine sediment core and this technique is validated with Pb210 chronology. The marine sediment core was sampled in front of the delta of Mittivakkat Glacier meltwater river in the Sermilik Fjord, SE Greenland, and is a proxy of the sediment delivery from a glacial drainage basin to a fjord. The estimated time series was based on automatic lamination detection (varves) on a line scan of the core using gray scale intensities, and covered the last two centuries. The estimated time series of sediment accumulation rates was coupled to modelled runoff from the Mittivakkat Glacier and compared with local climatic parameters (air temperature and precipitation) and with the Atlantic Multidecadal Oscillation (AMO) index. Maxima in the sediment accumulation rate at the bottom of the side-fjord, about 1 km from the delta, mostly depended on glacier ablation and consequently on changes in river runoff, which were initiated by the air temperature. This was especially the case during transition from colder periods towards warmer, where short-lived maxima in sediment accumulation rates were followed by lower rates, even though the temperature remained high. This suggested a quite rapid glacial response to changes in climatic forcing, and/or a hysteresis effect, where sediment stored in the glacier/valley system was evacuated soon after a temperature dependent increase in discharge. The air temperature was in turn controlled by the AMO index. [ABSTRACT FROM AUTHOR]

Ceratopsid dinosaurs represent one of the best known dinosaur groups in the Late Cretaceous, and their unquestionable fossil records are exclusively restricted to western North America. Here we report a new ceratopsid dinosaur, Sinoceratops zhuchengensis gen. et sp. nov., from the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. Cladistic analysis places this new taxon as the only known ceratopsid from outside North America, in a basal position within the Centrosaurinae. It is considerably larger than most other centrosaurines but similar in size to basal chasmosaurines. Furthermore, it is more similar to chasmosaurines than to other centrosaurines in several features, thus blurring the distinction of the two ceratopsid subgroups. This new find not only provides significant information on the morphological transition from non-ceratopsid to ceratopsid dinosaurs, but also complicates the biogeography of the Ceratopsidae, and further demonstrates that fossil sampling has profound effects on reconstructing dinosaurian biogeography. [ABSTRACT FROM AUTHOR]

The role of municipal solid waste (MSW) landfill leachate on the genesis of minor amounts of pyrite associated with gypsum in an otherwise predominantly evaporitic sequence was studied in geological and geochemical terms. The potential association between landfill leachate and the conditions required for bacterial reduction of sulfate and fixation of H2S as pyrite were examined. The lithological column was generally found to contain little or no Fe. The δ34S values for sulfates were consistent with previously reported data; however, the measured δ18O values were slightly higher. Sulfides disseminated in the marl/lutite exhibited higher δ34S values (≈−8‰) than gypsum-coating pyrite crystals (δ34S < −30‰). Dissolution of gypsum to sulfate and the supply of metabolizable organic matter and Fe required for H2S fixation as sulfides may have originated from landfill leachate. Intermittent availability of leachate, a result of the precipitation regime, can facilitate sulfur disproportionation and lead to fractionations as high as $$\delta_{\text{SO}_{4}^{2-}-{\text{S}^{2-}}}\approx - {\text{50}}\permille.$$ [ABSTRACT FROM AUTHOR]

The previously unknown enamel microstructure of a variety of Mesozoic and Paleogene mammals ranging from monotremes and docodonts to therians is described and characterized here. The novel information is used to explore the structural diversity of enamel in early mammals and to explore the impact of the new information for systematics. It is presently unclear whether enamel prisms arose several times during mammalian evolution or arose only once with several reversals to prismless structure. At least two undisputed reversions or simplifications are known—in the monotreme clade from Obdurodon to Ornithorhynchus (via Monotrematum?), and (perhaps more than once) within the clade from archaeocete to a variety of odontocete whales. Similarly, both prismatic and nonprismatic enamel is present among docodonts. Seven discrete characters showing enough morphological diversity to be of potential importance in phylogenetic reconstructions may be identified as a more appropriate summary of enamel microstructural diversity among mammaliaforms than the single character “prismatic enamel-present/absent” employed in recent matrices. Inclusion of five of these characters in the matrix of Luo et al. (2002) modifies the original topology by collapsing several nodes involving triconodonts and other nontribosphenic taxa. There is considerable support for prismatic enamel as a synapomorphy of trithelodonts plus Mammaliamorpha, and multituberculates appear to have small or “normal” sized prisms as the ancestral condition, with some (as yet) enigmatic changes to nonprismatic structure in some basal members of the group and the appearance of “gigantoprismatic” structure as an autapomorphic state of less inclusive clades. Other potential qualitative characters and the need for attaining appropriate methods to incorporate quantitative features may be important for future analyses. [ABSTRACT FROM AUTHOR]