A Caribbean epiphyte community preserved in Miocene Dominican amber

Cheiloceps arachnophila sp. nov. (Hemiptera: Fulgoroidea: Issidae) is described and illustrated based on a well-preserved adult male, representing the second species of Issidae known from Early Miocene (Burdigalian) Dominican amber. The only previously described issid from Dominican amber is transferred from Thionia Stål to Cheiloceps Uhler: Cheiloceps douglundbergi (Stroiński & Szwedo) comb. nov. Comparative notes on Cheiloceps and Thionia are provided.

The Palaeoproterozoic Hotazel BIF-Mn Formation as an archive of Earth's earliest oxygenation

Projecting species loss and turnover under climate change for 111 Chinese tree species

The leafy liverwort genus Lejeunea (Porellales, Jungermanniopsida) in Miocene Dominican amber

Global nitrogen (N) deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change.

Mycothalli, symbioses between liverworts and soil fungi, have not previously been recorded in the Arctic. Here, 13 species of leafy liverwort from west Spitsbergen in the High Arctic are examined for the symbiosis using epifluorescence microscopy and sequencing of fungal ribosomal (r)RNA genes amplified from plant tissues. Microscopy showed that intracellular hyphal coils, key indicators of the symbiosis, were frequent (>40% stem length colonized) in nine species of liverwort in the families Anastrophyllaceae, Lophoziaceae, Cephaloziellaceae, Cephaloziaceae and Scapaniaceae, with hyphae occurring frequently (>40% cells occupied) in the rhizoids of 10 species in the same families. Dark septate hyphae, apparently formed by ascomycetes, were frequent on the stems of members of the Anastrophyllaceae, Cephaloziellaceae and Cephaloziaceae, and typically those growing on acidic mine tailings. Sequencing of fungal rRNA genes showed the presence of nine distinct groups (based on a 3% cut-off for ITS sequence divergence) of the basidiomycete Serendipita in the Anastrophyllaceae and Lophoziaceae, with ordinations and correlative analyses showing the presence of the genus to be positively associated with the frequency of hyphal coils, the occurrence of which was positively associated with edaphic factors (soil δ15N value and concentrations of moisture, nitrogen, carbon and organic matter). We propose that the frequency of mycothalli in leafy liverworts on west Spitsbergen, which is an order of magnitude higher than at lower latitudes, may arise from benefits conferred by mycobionts on their hosts in the harsh environment of the High Arctic.

Sediment-hosted Pb-Zn deposits can be divided into two major subtypes. The first subtype is clastic-dominated lead-zinc (CD Pb-Zn) ores, which are hosted in shale, sandstone, siltstone, or mixed clastic rocks, or occur as carbonate replacement, within a CD sedimentary rock sequence. This subtype includes deposits that have been traditionally referred to as sedimentary exhalative (SEDEX) deposits. The CD Pb-Zn deposits occur in passive margins, back-arcs and continental rifts, and sag basins, which are tectonic settings that, in some cases, are transitional into one another. The second subtype of sediment-hosted Pb-Zn deposits is the Mississippi Valley-type (MVT Pb-Zn) that occurs in platform carbonate sequences, typically in passive-margin tectonic settings. Considering that the redox state of sulfur is one of the major controls on the extraction, transport, and deposition of Pb and Zn at shallow crustal sites, sediment-hosted Pb-Zn ores can be considered a special rock type that recorded the oxygenation of Earth’s hydrosphere. The emergence of CD and MVT deposits in the rock record between 2.02 Ga, the age of the earliest known deposit of these ores, and 1.85 to 1.58 Ga, a major period of CD Pb-Zn mineralization in Australia and India, corresponds to a time after the Great Oxygenation Event that occurred at ca 2.4 to 1.8 Ga. Contributing to the abundance of CD deposits at ca 1.85 to 1.58 Ga was the following: (1) enhanced oxidation of sulfides in the crust that provided sulfate to the hydrosphere and Pb and Zn to sediments; (2) development of major redox and compositional gradients in the oceans; (3) first formation of significant sulfate-bearing evaporites; (4) formation of red beds and oxidized aquifers, possibly containing easily extractable Pb and Zn; (5) evolution of sulfate-reducing bacteria; and (6) formation of large and long-lived basins on stable cratons. Although MVT and CD deposits appeared for the first time in Earth history at 2.02 Ga, only CD deposits were important repositories for Pb and Zn in sediments between the Great Oxygenation Event, until after the second oxidation of the atmosphere in the late Neoproterozic. Increased oxygenation of the oceans following the second oxidation event led to an abundance of evaporites, resulting oxidized brines, and a dramatic increase in the volume of coarse-grained and permeable carbonates of the Paleozoic carbonate platforms, which host many of the great MVT deposits. The MVT deposits reached their maximum abundance during the final assembly of Pangea from Devonian into the Carboniferous. This was also a time for important CD mineral deposit formation along passive margins in evaporative belts of Pangea. Following the breakup of Pangea, a new era of MVT ores began with the onset of the assembly of the Neosupercontinent. A significant limitation on interpreting the secular distribution of the deposits is that there is no way to quantitatively evaluate the removal of deposits from the rock record through tectonic recycling. Considering that most of the sedimentary rock record has been recycled, most sediment-hosted Pb-Zn deposits probably have also been destroyed by subduction and erosion, or modified by metamorphism and tectonism, so that they are no longer recognizable. Thus, the uneven secular distribution of sediment-hosted Pb-Zn deposits reflects the genesis of these deposits, linked to Earth’s evolving tectonic and geochemical systems, as well as an unknown amount of recycling of the sedimentary rock record.

At the end of the Permian, ca. 252 Ma ago, marine and terrestrial fauna were facing the most extensive mass extinction in Earth history (Raup and Sepkoski, 1982). 80%–95% of all species on Earth, on land and in the oceans, became extinct (Benton et al., 2004) within an estimated time interval of less than 200 k.y. to 700 k.y. (Huang et al., 2011; Shen et al., 2011). Among the prominent Paleozoic animal groups that vanished are fusulinid foraminifera, rugose and tabulate corals, and the arthropod class Trilobita. The numerous hypotheses about the causes of the mass extinction include various environmental changes, mostly related to the emplacement of the Siberian Traps large igneous province. The compilation of radiometric U/Pb ages for the mass extinction and the Siberian Traps demonstrate a temporal overlap of both events (Svensen et al., 2009). A prominent hypothesis for the mass extinction is an accentuated global climate change scenario induced by volcanic CO 2 degassing (e.g., Svensen et al., 2009) that triggered biotic responses in the sea and on land. But what do we know about the climate at this time in Earth history? The two main features of climate recorded in the geological archives are temperature and humidity i.e., the moisture that is available for plant growth, and to a certain extent rainfall patterns. Climate simulations model the general circulation patterns during Permian–Triassic times. The paleogeography was characterized by the supercontinent Pangea extending nearly from pole to pole, with large land masses in the mid-latitudes of the Northern and Southern Hemispheres, and with the Tethys Ocean in the tropics (e.g., Smith et al., 1994). Climate models and sensitivity experiments demonstrated that this paleogeography provided the preconditions for a monsoonal circulation with strong seasonality of temperatures and rainfall on the Tethyan coasts, and distinct northern and southern intertropical convergence zones (Fig. 1) (e.g., Kutzbach and Ziegler, 1993; Parrish, 1993). Moist conditions prevailed in middle and high latitudes and along the

The middle Ediacaran Period records one of the deepest negative carbonate carbon isotope (δ13Ccarb) excursions in Earth history (termed the Shuram excursion). This excursion is argued by many to represent a large perturbation of the global carbon cycle. If true, this event may also have induced significant changes in the nitrogen cycle, because carbon and nitrogen are intimately coupled in the global ocean. However, the response of the nitrogen cycle to the Shuram excursion remains ambiguous. Here, we reported high resolution bulk nitrogen isotope (δ15N) and organic carbon isotope (δ13Corg) data from the upper Doushantuo Formation in two well-preserved sections (Jiulongwan and Xiangerwan) in South China. The Shuram-equivalent excursion is well developed in both localities, and our results show a synchronous decrease in δ15N across the event. This observation is further supported by bootstrapping simulations taking into account all published δ15N data from the Doushantuo Formation. Isotopic mass balance calculations suggest that the decrease in δ15N during the Shuram excursion is best explained by the reduction of isotopic fractionation associated with water column denitrification (εwd) in response to feedbacks between carbon and nitrogen cycling, which were modulated by changes in primary productivity and recycled nutrient elements through remineralization of organic matter. The study presented here thus offers a new perspective for coupled variations in carbon and nitrogen cycles and sheds new light on this critical time in Earth history.

The known Montana flora of thalloid Hepaticae consists of 26 species in 17 genera and 11 families. The following five species are reported new to Montana: Riccardia multifida (L.) S. Gray, R. palmata (Hedw.) Carruth., Lunularia cruciata (L.) Dum., Riccia fluitans L., and Ricciocarpus natans (L.) Corda. This catalog of taxa is based upon the study of 800 collections. The species belong to several floristic elements: circumpolar, boreal montane (26.9% of the reported taxa); circumpolar, arctic-temperate alpine-montane (19.2%); circumpolar, boreal-temperate montane (19.2%); circumpolar, arctic-alpine (7.7%); circumpolar, temperate (19.2%); circumpolar, cordilleran (3.9%) and American, cordilleran (3.9%). Jones (1910) listed twenty-four species of liverworts in Montana. Among these species, Asterella ludwigii (under A. gracilis), Marchantia polymorpha and Metzgeria pubescens were thalloid liverworts. Actually these species were all collected by Holzinger from the Glacier National Park and were determined by Evans. Evans (1917) listed Riccia frostii, using the material collected from the Great Falls area. Clark and Frye (1928) listed the following nine species of thalloid hepatics in Montana: Asterella lindenbergiana, A. ludwigii, A. saccata, Conocephalum conicum, Marchantia polymorpha, Metzgeria pubescens, Pellia endiviifolia, Riccia frostii and Riccardia latifrons. In 1931 they listed Pellia neesiana from Glacier National Park, making a total of ten. In 1934 they listed an additional three species of hepatics as new to Montana flora. Among these, Clevea hyalina and Riccia crystallina were thalloid liverworts. In the same year Brinkman listed sixty species of hepatics in Montana of which the following eleven species were thalloid liverworts: Asterella lindenbergiana, A. ludwigii, A. saccata, Conocephalum conicum, Marchantia polymorpha, Metzgeria pubescens, Pellia endiviifolia, P. neesiana, Preissia quadrata, Riccardia latifrons and Riccia frostii. In 1937 he also listed eight species, including Pellia epiphylla and Riccia sorocarpa, as new to the hepatic flora of Montana. In the same year Clark and Frye also added Pellia epiphylla and Riccia sorocarpa to the thalloid hepatic flora of Montana. Later, Frye and Clark (1937-1947) listed the following fifteen species for the thalloid hepatic flora of Montana: Asterella lindenbergiana, A. ludwigii, A. saccata, Clevea hyalina, Conocephalum conicum, Marchantia polymorpha, Metzgeria pubescens, 1I thank President Msgr. Anthony Brown, Dean Dr. Francis DiRocco, Chairman Prof. Edward Peressini, Rev. Dr. Francis McInnis and Sister Maryann Benoit for their assistance. I especially wish to thank Drs. W. E. Booth, L. H. Harvey, F. G. Hermann and W. B. Schofield for the loan of herbarium material and for the use of their collections. ' Department of Biology, College of Great Falls, Great Falls, Montana 59405. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 05:41:38 UTC All use subject to http://about.jstor.org/terms 1977] HONG: THALLOID HEPATICAE OF MONTANA 271 Pellia endiviifolia, P. epiphylla, P. neesiana, Preissia quadrata, Riccardia latifrons, Riccia crystallina, R. frostii and R. sorocarpa. Hong (1967, 1968a,b) listed eight new species of thalloid liverworts. In 1969 Hermann listed seventeen species of thalloid liverworts with seventy species of leafy liverworts from Glacier National Park. The above mentioned hepatic publications except those of Frye and Clark (19371947) are mainly concerned with leafy liverworts, and no papers were published dealing only with thalloid liverworts. The aim of this study is to report the taxa of thalloid liverworts which occur in Montana and to compare this flora to that of neighboring states and provinces of Canada. I have made over one hundred twenty collecting trips throughout the state since 1965 and have made over eight hundred collections of thalloid Hepaticae. This report is based on the above collections, herbarium specimens of the University of Montana (MONTU) and Montana State University (MONT) and literature reports from the previously mentioned papers as well as those in the following: Bird, 1973a; Bird & Hong, 1969, 1975; Evans, 1920; Hong, 1975, 1976, 1977; Porter, 1933, 1935; Schofield, 1968; Schuster, 1953. In general the arrangement of families follows the classification of Arnell (1956) and Schuster (1966). The species and genera are arranged alphabetically within the families. Collection numbers are mine and where more than two collections were made at a given locality, the number of collections is given in parentheses. The author listed in the last parentheses under each taxon indicates a record that is without a specifically named locality. The distribution element of each taxon is described through the system of Bird and Hong (1969, 1975) and Bird (1973b). Voucher specimens were deposited at the College of Great Falls. Counties within the state and bordering states and provinces are shown in Hong (1975).

<p>Although anoxia is rare in modern oceans, the marine stratigraphic record is punctuated by sedimentary and geochemical evidence for episodes of widespread oceanic anoxia. The last time in Earth history that a large volume of the ocean became anoxic was in the middle Cretaceous: black organic-carbon-rich muds were repeatedly preserved on the deep seafloor during oceanic anoxic events (OAEs).</p><p>Sedimentary and geochemical evidence for oceanic anoxia during OAEs comes mainly from the Atlantic and Tethys Oceans. Data from the Pacific Ocean, which was the largest ocean basin in the middle Cretaceous, is scarce and equivocal. Based on black shales deposited at depths of about 500–1500 m on seamounts, Monteiro et al. (2012) have suggested that at least 50 vol% of the ocean was anoxic at the climax of Cretaceous oceanic anoxia during the late Cenomanian. They also included a single black shale at DSDP Site 585 in the Mariana Basin as evidence for anoxia in the deep Pacific. We will show, however, that this is a mud turbidite reworked from shallower water.</p><p>For this study, we reviewed all available data and publications from scientific drilling that recovered Cretaceous sediments in the Pacific Ocean. The little available Cretaceous record from the Pacific consists mainly of well-oxidized sediments. The exceptions are black shales that occur at depths of about 500–1500 m on seamounts. Takashima et al. (2011) have shown that the Asian and North American continental margins of the Pacific were indeed oxic for most of the late Cenomanian OAE. </p><p>We used a new paleomagnetic reconstruction of the Pacific plate back to 150 Ma to show that all investigated Cretaceous organic-carbon-rich sediments in the Pacific Ocean were deposited while the site was located in the Equatorial Divergence Zone (10°S to 10°N). We therefore argue that organic matter deposition in the Pacific Ocean might not have been directly related to OAEs, but rather be associated with the passage of seamounts beneath the equatorial belt of high productivity.</p><p>Several authors have challenged suggestions that OAEs were characterized by globally pervasive anoxic deep water and pointed to the difficulty in sustaining whole-ocean anoxia, even in warm oceans. We agree and our results show that oceanic anoxia in the Pacific is a local phenomenon superposed on a global trend of expanded oxygen minima in the ocean.</p>

No abstract available. doi:10.2204/iodp.sd.6.12.2008

The Late Palaeozoic period was an important time in Earth history, primarily as a result of the formation of Pangea and the Gondwana glaciations that had direct influences in high latitudes and indirect, but no less important, effects in low latitudes. This study documents and interprets the isotopic record for the Early–Middle Permian in northern Gondwana from detailed fieldwork in the Venezuelan Andes. Sr-isotope dating of well-preserved brachiopod shells suggests a Kungurian age from samples located within the middle part of the Palmarito Formation. δ 13 C data show a long-term trend through the section towards more positive values, but with some very negative δ 13 C values suggesting carbonates affected by pedogenic processes. In the middle part of the succession, major excursions in δ 13 C and δ 18 O show a strong connection with glacial–deglacial events during the Early–Middle Permian. Overall results presented here fill an important gap in the regional palaeogeography and, therefore, have significant implications for the palaeoclimate and palaeoceanography of this Late Palaeozoic time.

Neoproterozoic continental arc system along the NW margin of Rodinia supercontinent: Constraints from geochronological and geochemical studies of Neoproterozoic granitoids in the Diancangshan Massif

The Ordovician Period has emerged as a highly dynamic time in Earth history. Comprehensive work on chrono-, chemo- and biostratigraphy has resulted in an overall well-constrained systemic framework, but several local successions around the globe still await detailed analysis in many respects. Herein we perform a high-resolution analysis of abiotic and biotic signals in the Lynna River section, a key locality in northwestern Russia. As this section has been pivotal in documenting the temporal evolution of the Great Ordovician Biodiversification Event on Baltica, the macroscopic and microscopic characteristics of the local succession reveal important paleoenvironmental information that ties into the global development during the Middle Ordovician. The results add particularly to the understanding of the characteristics and large-scale sedimentary ‘behavior’ of the Baltoscandian paleobasin. Microfacies vary consistently with the macroscopic appearance of the rocks, with intervals characterized by competent limestone being associated with coarser carbonate textures and intervals dominated by marly beds associated with finer textures. Along with carbonate textures, fossil grain assemblages vary in a rhythmic (~cyclic) manner. The local rocks are commonly partly dolomitized, with the proportion of dolomitization increasing up-section. Regional comparisons suggest that the changes in overall macro- and microfacies were strongly related to variations in sea level. New high-resolution conodont biostratigraphic data largely confirm previous regional correlations based on lithostratigraphy and trilobite faunas, and enable more robust correlations worldwide.