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1.
The Lower Permian in the central Southern Alps yields an important low-diversity fossil assemblage which was deposited in a varied continental setting, showing mainly alluvial fan to lacustrine and, locally, playa-like floodplain environments. The present study is not taxonomical and its objective is to make a first report of new invertebrate organisms and trackways discovered in the Orobic and Collio basins. Such a fossil record, which comprises freshwater jellyfishes, arthropod tracks, stromatolites, algae and other organisms, will further our knowledge about the local and regional geological history of the central-western Southern Alps and improve our understanding of Early Permian palaeoenvironments. On the whole, in both intramontane basins the ichnodiversity and fossil content decreases from a stratigraphic lower portion, mainly lacustrine and alluvial, towards an upper one, characterised by coarse alluvial deposits to floodplain fines. On the basis of both the already known palaeontological data from the two basins, mainly macroflora and tetrapod footprint associations, and the recently discovered taxa, we tried to make reliable palaeoenvironmental inferences and, possibly, hypothesise on a climatic change, which could have occurred during the Early Permian. 相似文献
2.
Qiuan Zhu Changhui Peng Philippe Ciais Hong Jiang Jinxun Liu Philippe Bousquet Shiqin Li Jie Chang Xiuqin Fang Xiaolu Zhou Huai Chen Shirong Liu Guanghui Lin Peng Gong Meng Wang Han Wang Wenhua Xiang Jing Chen 《Global Change Biology》2017,23(11):4706-4716
Methane (CH4) emissions from tropical wetlands contribute 60%–80% of global natural wetland CH4 emissions. Decreased wetland CH4 emissions can act as a negative feedback mechanism for future climate warming and vice versa. The impact of the El Niño–Southern Oscillation (ENSO) on CH4 emissions from wetlands remains poorly quantified at both regional and global scales, and El Niño events are expected to become more severe based on climate models’ projections. We use a process‐based model of global wetland CH4 emissions to investigate the impacts of the ENSO on CH4 emissions in tropical wetlands for the period from 1950 to 2012. The results show that CH4 emissions from tropical wetlands respond strongly to repeated ENSO events, with negative anomalies occurring during El Niño periods and with positive anomalies occurring during La Niña periods. An approximately 8‐month time lag was detected between tropical wetland CH4 emissions and ENSO events, which was caused by the combined time lag effects of ENSO events on precipitation and temperature over tropical wetlands. The ENSO can explain 49% of interannual variations for tropical wetland CH4 emissions. Furthermore, relative to neutral years, changes in temperature have much stronger effects on tropical wetland CH4 emissions than the changes in precipitation during ENSO periods. The occurrence of several El Niño events contributed to a lower decadal mean growth rate in atmospheric CH4 concentrations throughout the 1980s and 1990s and to stable atmospheric CH4 concentrations from 1999 to 2006, resulting in negative feedback to global warming. 相似文献
3.
Glasspool I 《Review of Palaeobotany and Palynology》2000,110(3-4):209-227
More than 300 megaspore specimens have been recovered from samples from the Late Permian, Lower Whybrow coal seam of the Wittingham Coal Measures of the Sydney Basin. Only two species are recognised: Singhisporites surangei (Singh) Potonié, emend. and a new species of Singhisporites. Species distribution within the seam is controlled by a major fire event, as recognised by coal petrology and mesofossil content: Singhisporites surangei is dominant before the event, but following it, it is subordinate to the new species.
The abundance of megaspores recovered has allowed recognition of the full range of morphologic variation of Singhisporites surangei, which encompasses specimens assigned previously to Singraulispora Pant & Mishra, 1986 and Mammilaespora Pant & Srivastava, 1961; both are regarded as junior synonyms of Singhisporites Potonié, emend. Ultrastructurally, the new species shows affinities with Mesozoic isoetalean megaspores. 相似文献
4.
Glossopteris-type leaves are the most abundant floristic element from the Gondwanan continent and are recorded throughout the Permian, which was a period of extreme icehouse-to-hothouse climatic global change. Fossil leaf traits can be useful for the reconstruction of palaeoenvironments and identification of climatic changes throughout geological time, but the conservative morphology of Glossopteris leaves has thus far made them difficult to use for this purpose. If the characters of Glossopteris can be better quantified then it should make them useful for tracking environmental changes over a wide geographical area and over a long time interval. Venation density is a highly variable leaf trait that might be useful for this purpose. This trait can be calculated, usually as vein length per centimetre squared, but this can be a time-consuming procedure. In this paper we propose a new rapid method to estimate venation density in a conical sector of Glossopteris leaf lamina using an accurate linear model whose predictors are three linear venation densities, measured as veins per centimetre. In addition to substantially reducing the data collection time, it is less biased and more reproducible than methods applied previously with this leaf type. Using this more robust method, preliminary results significantly distinguish the venation densities of leaves produced in wet and drier ecosystems, matching a pattern similar to modern plants. This is the first survey using a large sample size to reveal that environmental stress controlled the vein architecture of Palaeozoic plants, in a manner similar to plants in modern ecosystems. 相似文献
5.
The distribution and area of temporary wetlands across the arid zone of Australia are highly variable. Any change in their distribution or extent due to climate change and/or extraction of water has the potential to adversely impact dependent biota. Satellite imagery was used to determine the spatial and temporal distribution of wetlands across arid Australia over an 11‐year period. Synoptic climate data were examined to identify the weather systems that caused wetland filling events. Simple threshold models relating rainfall to wetland filling for seven large regions of Australia were developed to examine patterns of wetland filling over the last 100 years. These data were used to examine the climatic processes that drive wetland filling and the likely impacts of climate change on wetland distribution. The strongest climatic influence on wetland filling in the arid zone was tropical weather systems. Their influence extended into southern regions and their effects were often widespread. Variation in wetland area in all regions of the arid zone was high. The Lake Eyre Basin experienced more large flood events than other regions and had the most large, persistent wetlands that remain unregulated by humans. Hindcasting of past filling events indicated that there was a general pattern of frequent wetland filling across inland Australia in the 1910s, 1950s and 1970s, and less frequent wetland filling in the late 1920s, 1930s and 1960s. Furthermore, there appeared to be no period greater than 12 months over the previous 95 years when there was no predicted wetland filling in the arid zone. Wetland ecosystems dependent on a few infrequent heavy rainfalls are clearly vulnerable to any change in frequency or magnitude of these events. Climate change that results in a drying or reduced frequency of large flood events, exacerbated by extraction of water for agriculture, could be catastrophic for some biota, particularly waterbirds, which use a mosaic of wetland habitat at broad spatial scales. 相似文献
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内蒙古乌达地区早二叠世晋囊蕨属一新种 总被引：3，自引：0，他引：3
通过扫描电镜研究,建立了内蒙古中部乌达地区下二叠统山西组晋囊蕨诉一个新种Ｃｈａｎｓｉｔｈｅｃａ ｗｕｄａｅｎｓｉｓ ｓｐ ．ｏｎｖ．。新种的小心片Ｓｐｈｅｎｏｐｔｅｒｉｓ型,囊群椭圆形,由４～１０个孢子囊组成,着生一示羽片背面,位于中脉的两侧。环带横列于孢子囊的上部,完全,单排细胞,细胞数目约为１８个,这些特征表明新种属于里白科。 相似文献
8.
Two new genera (Sinosphaera and Trigonosphaera), including two new species and another left in open nomenclature, are described from the Changxingian (upper Permian) of southern Guangxi, southern China. They are characterized by a single spherical, subspherical or rounded triangular cortical shell composed of two spongy layers and the likely absence of both a medullary shell and internal spicule. They are tentatively grouped within the family Xiphostylidae Haeckel, 1881 and are considered as the most primitive representatives of this family. 相似文献
9.
Abstract: A new South American Early Triassic stereospondyl is described and considered to represent a new taxon, Cabralia lavinai gen. et sp. nov. The material consists of two well-preserved skull fragments. According to recent phylogenetic analyses of rhytidosteids and related taxa, the new taxon is referred to the Rhytidosteidae based on the presence of orbits that are located close to the skull margins, an otic notch that is reduced to an embayment, tabular horns that are reduced and broad based, a straight posterior margin of the palate, skull sculpture with nodules and pustules, and a 'twisted' quadrate ramus of the pterygoid. The presence of a prominent lacrimal bone suggests a basal position within Rhytidosteidae for C. lavinai , and possibly a close relationship with the Indian Indobrachyops , because all other known rhytidosteids exhibit the derived condition of an absence of the lacrimal. The presence of a basal rhytidosteid in the Paraná Basin of South America strongly supports previous hypotheses of a Gondwanan origin and radiation of stereospondyl temnospondyls during the Early Triassic, but leaves unresolved the question of where exactly they arose within that region. 相似文献
10.
Mark B. Bush Alexander Correa‐Metrio Robert van Woesik Courtney R. Shadik Crystal N. H. McMichael 《Global Change Biology》2017,23(8):3181-3192
The long‐term interaction between human activity and climate is subject to increasing scrutiny. Humans homogenize landscapes through deforestation, agriculture, and burning and thereby might reduce the capacity of landscapes to provide archives of climate change. Alternatively, land‐use change might overwhelm natural buffering and amplify latent climate signals, rendering them detectable. Here we examine a sub‐annually resolved sedimentary record from Lake Sauce in the western Amazonian lowlands that spans 6900 years. Finely‐laminated sediments were deposited from ca. 5000 years ago until the present, and human activity in the watershed was revealed through the presence of charcoal and maize agriculture. The laminations, analyzed for color content and bandwidth, showed distinctive changes that were coupled to more frequent occurrence of fossil maize pollen. As agricultural activity intensified ca. 2200 cal. BP, the 2‐ to 8‐year periodicity characteristic of El Niño–Southern Oscillation became evident in the record. These agricultural activities appeared to have amplified an existing, but subtle climatic signal that was previously absorbed by natural vegetation. When agricultural activity slowed, or land use around Lake Sauce changed at ca. 800 cal. BP, the signal of El Niño–Southern Oscillation (ENSO) activity became erratic. 相似文献
11.
Hagner-Holler S Kusche K Hembach A Burmester T 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2005,175(6):445-452
Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phylum. Among the Crustacea, hemocyanins are apparently restricted to the Malacostraca. While well-studied in Decapoda, no hemocyanin sequence has been known from the ’lower’ Malacostraca. The hemocyanin of the amphipod Gammarus roeseli is a hexamer that consists of at least five distinct subunits. The complete cDNA sequence of one subunit and a tentative partial sequence of another subunit have been determined. The complete G. roeseli hemocyanin subunit comprises 2,150 bp, which translates in a protein of 672 amino acids with a molecular mass of 76.3 kDa. Phylogenetic analyses show that, in contrast to previous assumptions, the amphipod hemocyanins do not belong to the α-type of crustacean hemocyanin subunits. Rather, amphipod hemocyanins split from the clade leading to α and γ-subunits most likely at the time of separation of peracarid and eucarid Crustacea about 300 million years ago. Molecular clock analyses further suggest that the divergence of β-type subunits and other crustacean hemocyanins occurred around 315 million years ago (MYA) in the malacostracan stemline, while α- and γ-type subunits separated 258 MYA, and pseudohemocyanins and γ-subunits 210 million years ago. 相似文献
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Seven bryozoan species belonging to the Order Rhabdomesida and Order Cystoporida are described from the Permian deposits exposed near the small town of Deh-e Mohammad, Shotori Mountains (northeastern Iran): Rhabdomeson cf. consimile Bassler, Pamirella nitida Gorjunova, Clausotrypa conferta Bassler, Streblotrypa (Streblotrypa) elegans Sakagami, Streblotrypa (Streblascopora) supernodata nov. sp., Cystodictya sp., and Filiramoporina cf. kretaphilia Fry and Cuffey. The described fauna identifies the age of the Jamal Formation at the locality near Deh-e Mohammad as Lower Permian. It displays palaeobiogeographic connections to the Lower Permian of Pamir (Tajikistan), Indonesia, Thailand and Kansas (North America). 相似文献
14.
NEW MATERIAL OF HELICOPRIONID SHARK FROM LIANYUAN OF HUNAN 总被引：1，自引：0，他引：1
Edestiforme8obruchev,1953HelicoprionidaeKarpinsky,l9llHunanohelicoprionxiandongensi8gen.etsp.nov.Ho1otypeApartoftooth-row,withtenteethfragments,no.XKG-F9lo1,Xi-angtanMininglnstitute.LocalityandhorizonXiandong,Lianyuan,Hunan;QixiaFormation,theLowerPermian.DisgnosisTeethofcuttingtype,lateral1ycompressed;cuttingb1adeserratedanteriorlyandposteriorly,serrationtiny;lateralwingrelativelywide,serrationontheanteriormarginirreguIarandnoserrationontheposteriormargin,"intermediateregionwithoutenam… 相似文献
15.
A parsimony analysis of 'higher' temnospondyls (all temnospondyls descended from the common ancestor of Eryops and Parotosuchus ) was performed using 37 terminal taxa and 121 osteological characters. Bremer support values for each internal node were calculated as a measure of clade strength. Additionally, the shortest trees that conformed to some alternative hypotheses were searched for. The following new taxa are established on the basis of the results: Euskelia (the clade containing the Eryopoidea and Dissorophoidea), Limnarchia (the clade containing Trimerorhachidae, Dvinosauroidea, Archegosauroidea and Stereospondyli), Dvinosauria (the clade containing Trimerorhachidae and Dvinosauroidea), Stereo-spondylomorpha (the clade containing Archegosauroidea and Stereospondyli), Capitosauria (the clade containing Lydekkerina and 'capitosauroids'), and Trematosauria (the clade containing Trematosauroidea, Rhytidosteidae, Plagiosauroidea, Metoposauroidea and Brachyopoidea). The monophyly of the assemblage of Mesozoic families called the Stereospondyli by Romer is supported. The dominance of the Stereospondyli in the Mesozoic and its rarity in the Palaeozoic is discussed. It is suggested that the radiation of the diverse stereospondyl clades, the Capitosauria and Trematosauria, began in the Late Permian of Gondwana, in a 'safe haven' that was less severely affected by the Late Permian extinction event. It is further speculated that the 'safe haven' was located in Antarctica, or possibly Australia. 相似文献
16.
《Palaeoworld》2020,29(3):552-567
The first radiolarian fauna obtained from Permian carbonates in Thailand is of late Kungurian age and is present in the basal beds of the carbonate–mudstone–chert Phap Pha Formation, Ratburi Group. This succession contains several species of the radiolarian Pseudoalbaillella, and some sponge spicules. The radiolarian fauna consists of abundant Pseudoalbaillella aidensis and P. elegans together with P. fusiformis, P. longtanensis, P. m. rhombothoracata and P. sp. A. Other species include P. cf. aidensis, P. cf. elongata, P. cf. fusiformis, P. cf. ishigai, P. cf. lomentaria, P. cf. longicornis, P. cf. longtanensis, P. cf. ornata, P. cf. simplex, P. cf. m. scalprata, P. cf. m. postscalprata, P. cf. u–forma m. I, P. cf. u–forma m. II, and P. spp. The radiolarian assemblage suggests its correlation to the P. longtanensis Zone which, in turn, is correlated to the P. ishigai Zone of late Kungurian age. The occurrence of an abundant but generically low–diversity radiolarian fauna suggests restricted physical conditions and, with other evidence, suggests deposition along a cool deglaciating or deglaciated continental margin with an abundance of silica possibly provided by glacial meltwaters. The abundant chert in the Phap Pha Formation is part of the widespread Permian Chert Event. 相似文献
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Abstract: The genus Umkomasia Thomas, a female fructification of Dicroidium , is reported from Late Permian beds exposed in the Behra Rivulet near the village of Karaonda in the Tatapani-Ramkola Coalfield, Chhattisgarh, India. This is the first record of this genus from the Late Permian, and from Indian Gondwana. Two species have been recognized: Umkomasia polycarpa Holmes and U. uniramia Axsmith, Taylor, Taylor and Cuneo. The find suggests that the genus Dicroidium appeared in the Late Permian before reaching its acme in the Middle–Upper Triassic. 相似文献
19.
Graciela Piñeiro Jorge Ferigolo Melitta Meneghel Michel Laurin 《Historical Biology》2013,25(6):620-630
The earliest undisputed crown-group amniotes date back to the Late Carboniferous, but the fossil record of amniotic eggs and embryos is very sparse, with the oldest described examples being from the Triassic. Here, we report exceptional, well-preserved amniotic mesosaur embryos from the Early Permian of Uruguay and Brazil. These embryos provide the earliest direct evidence of reproductive biology in Paleozoic amniotes. The absence of a recognisable eggshell and the occurrence of a partially articulated, but well-preserved embryo within an adult individual suggest that mesosaurs were viviparous or that they laid eggs in advanced stages of development. Our finds represent the only known documentation of amniotic embryos in the Paleozoic and the earliest known case of viviparity, thus extending the record of these reproductive strategies by 90 and 60 Ma, respectively. 相似文献
20.
《Comptes rendus biologies》2019,342(5-6):230-235
Discocyrtoides pinorum sp. nov. is described from the conifers forest in Paraná State, Southern Brazil. This is the second species of Discocyrtoides Mello-Leitão, 1923, the other being known from São Paulo State. It is remarkable for having greenish/yellowish spots in the dorsal scutum highly contrasting with the brown background, a feature rare in Mitobatinae, hitherto known only for Ruschia Mello-Leitão, 1940. It is the first record of this genus for Paraná State (WWF Ecoregion NT0101, Araucaria moist forests). Terminology for the male genitalia of the Mitobatinae is defined and illustrated. 相似文献