甘肃临夏盆地的渐新世巨犀化石

描述了 2种巨犀化石 :霍尔果斯准噶尔巨犀 (Dzungariotheriumorgosense)和牙沟副巨犀(新种 ) (Paraceratheriumyagouensesp .nov.)。新种的主要特征是 :个体小 ;上颊齿齿冠高 ,有薄层白垩质覆盖 ;DP2～M1反前刺大 ,原尖后收缩沟明显 ,次尖有深的前收缩沟 ,中谷和后凹中常有附属小柱等。巨犀的演化历史可能比过去想象的更复杂。Indricotherium、Dzungariotherium和Paraceratherium为代表不同进化水平和支系的 3个属 ,不应合并为Paraceratherium一属。牙沟含巨犀化石层位的地质时代为晚渐新世。     

苏北盆地高邮凹陷D1井白垩纪-古近纪微体古生物地层及沉积环境

高邮凹陷D1井富含介形虫、轮藻和孢粉等化石。通过系统的微体古生物分析,首次对该地区白垩纪一古近纪微体古生物地层进行了精确划分,从下到上共建立11个化石组合：其中介形虫4个,轮藻4个,孢粉3个。文中还简要探讨了沉积环境演变,为该地区油气勘探提供有力的生物地层依据。     

从塔北隆起奥陶纪钙藻化石探讨奥陶纪的古环境

塔里木盆地塔北隆起轮南46井、英买1、2井奥陶纪石灰岩内含有大量的钙藻化石、蓝细菌以及疑难微体化石。这些钻井岩芯均在深达5000-6200m的地下深部取得。钙藻主要为绿藻类的Dasyporella,Ver‘miporella,Moniliporella以及?Plexa;红藻类的管孔藻类Solenoporaceans;钙化蓝细菌则有Girvanella,Botomaella,?Subtifloria等;疑难微体化石有Bevocastria,Nuia,Rothpletzella。这些钙藻生活于热带或亚热带正常盐度的浅海水内,其水深不到20m。世界各地的奥陶纪Vermiporella均位于古赤道的两侧,这表明它们是在气候炎热、温暖海水中生活的一类海洋藻类。Girvanella以藻灰结核和内碎屑最为常见,某些球粒可能代表Girvanella破碎后形成的单管或小棒。塔里木盆地钙藻植物群相似于哈萨克斯坦、波罗的海周围地区以及北美同时代植物群,这表明这些钙藻和蓝细菌化石具有遍布于全球的性质。塔北隆起早、中奥陶世沉积属于典型的碳酸盐岩台地相沉积。到晚奥陶世时,碳酸盐岩沉积被浅水陆棚沉积所取代,以陆源碎屑岩为主,夹少量的碳酸盐岩。     

内蒙古锡林河流域不同植物群落中羊草和糙隐子草水分利用效率的变异

用稳定性同位素技术,研究了锡林河流域不同群落和生境下羊草(Leymus chinensis ( Trin.) Tzvel.)和糙隐子草(Cleistogenes squarrosa (Trin.) Keng.)叶片δ13C值及其水分利用效率的变化.结果表明,在不同生境下,羊草和糙隐子草叶片δ13C 值随土壤水分含量的降低而增大,并与不同土层土壤水分含量均表现出极显著的线性负相关关系;而二者的叶片水分含量与土壤水分含量无显著的相关关系.这一结果说明,羊草和糙隐子草的水分利用效率均随土壤水分含量的降低而提高,而叶片水分含量保持相对稳定.这两种植物可能通过调节气孔导度、提高水分利用效率和增强渗透调节能力等生理生态机制适应水分状况不同的生境,从而使它们能够在锡林河流域不同植物群落中广泛分布并成为建群种或优势种.     

Berriasian–Aptian black shales of the Maiolica formation (Lombardian Basin, Southern Alps, Northern Italy): local to global events

The Lower Cretaceous Maiolica Formation represents the classic pelagic succession of the Apulian margin of the Tethys Ocean, in the Southern Alps. It consists of white calcilutites with minor marly layers and black shales. A multidisciplinary study including lithostratigraphy, nannofossil assemblage composition and organic geochemistry was performed on two composite sections in order to characterise the marl–shale layers that record production and storage of organic matter (OM) and terrigenous input in the Berriasian–Aptian interval. Such layers are associated with turbidite deposition and bottom current activity in the Late Berriasian–earliest Valanginian, Late Valanginian and Early Aptian. The uppermost Hauterivian–Barremian black shales alternate with pelagic calcilutites, forming an interval barren of redeposited layers. The quantity of organic carbon increases from the Berriasian to the Barremian; the background composition of the kerogen is continental-dominated, with varying proportions of marine-derived OM. Preservation of OM did not necessarily occur under anoxic conditions; on the contrary, storage of OM probably resulted from enhanced terrestrial input of nutrients, siliciclastics, woody and herbaceous fragments, inducing mesotrophic conditions and increased primary productivity. Higher fertility of surface waters during the Late Valanginian and Early Aptian is reflected by distinctive decreases in abundance of oligotrophic nannoconids and increase in abundance of mesotrophic Diazomatholithus in the Valanginian. During the Barremian, the rhythmic establishment of eutrophic conditions, documented by the highest amounts of marine OM, determined high-frequency fluctuations in nannoconid abundance. The Early Aptian nannoconid crisis is interpreted as the result of a major climate change and enhanced primary productivity. Variations of calcareous nannofloras, as well as changes of lithology and OM, which we describe in the Lower Cretaceous Maiolica Formation of the Lombardian Basin, can also be recognised in coeval units from other sites of the Apulian side of the Tethys. Similar episodes of siliciclastic and terrestrial OM accumulation and major changes in calcareous nannofossils are also recorded in the Upper Valanginian and Lower Aptian pelagic sediments of the Tethys, Atlantic and, partly, Pacific oceans. Such nannofossil variations are coeval with positive excursions of the δ¹³C curve and suggest perturbations of the bio-geochemical cycles at a global scale. Additional minor changes in siliciclastic and terrestrial OM accumulation as well as in nannofloras are probably the result of local events, strictly related to the physiography and evolution of the Tethyan margin.     

吉林延边智新盆地大拉子组孢粉组合

本文对产自吉林延边地区智新盆地大拉子组上段的孢子花粉进行了系统研究,共计36属91种,另有疑源类化石1属2种,组成以Classopollis-Cicatricosisporites为代表的孢粉组合。根据组合内一些重要分子的地质时限讨论和与相关组合的对比。其时代应归为早白垩世晚期,根据疑源类和主要孢粉属种可能的母体植物生长环境,推测在早白恶世晚期吉林延边地区智新镇是一个宁静的湖泊,气候温暖,干燥。     

Multilevel studies on the two phenological forms of Large Blue (Maculinea arion) (Lepidoptera: Lycaenidae)

The main goal of our research was to study comprehensively the differences between the two phenological forms of the socially parasitic and globally threatened Large Blue (Maculinea arion) in the Carpathian Basin using four character sets (mitochondrial sequences, allozymes, male genitalia and wing morphometrics). Comparative analyses of distance matrices, phylogenetic trees and ordination patterns have been applied. The genetic and morphometric patterns revealed by our studies were discordant. While we experienced a significant differentiation between the ‘spring’ and ‘summer type’ of M. arion in both wing and genital traits, the two phenological forms did not show any genetic differentiation on two mitochondrial loci and in allozymes. At the same time, all individuals were infected by Wolbachia. Although certain wing traits may not represent reliable tracers of phylogeny because of the particular adaptive significance, the wing characteristics involved in our research are probably determined genetically. Additionally, the significant differentiation of male genitalia also indicates incipient prezygotic isolation arising from phenological differentiation between the ‘spring and summer arion’. It is possible that all extant differences between the two forms are attributable to (1) different host‐ant use, (2) incipient speciation, (3) cytoplasmatic incompatibility (CI) by Wolbachia or the combination of these factors. In addition, discordant results indicate that the combined use of different approaches and data sets is strictly necessary to clarify systematic and evolutionary relationships.     

Environmental and human factors influencing rare plant local occurrence, extinction and persistence: a 115-year study in the Mediterranean region

Aim Assessing whether environmental and human factors influenced the spatial distribution and the dynamics of regionally rare plant species since the late nineteenth century, and whether these spatial and temporal patterns of rare species occurrences differ according to their chorology (level of endemism and biogeographic affinity). Location An area extending over 6250 km² in the French Mediterranean Region. Methods We used two botanical surveys achieved in 1886 and in 2001, and considered species rare if occurring in only one or two sites in the study area. Each rare species was assigned to a group of endemism level (restricted endemic, non‐endemic), and of biogeographic affinity (Mediterranean, South/Central European, Mountain, Eurosiberian). A 1 × 1 km grid was applied to the study zone. Generalized linear models were developed to study the spatial distribution and the fate of rare species occurrences (local extinction vs. local persistence between 1886 and 2001), as a function of environmental and human variables. Multivariate analyses were used to test whether the spatial distribution and the fate of rare species occurrences differed according to their chorology. Results In 2001, rare species as a whole tended to occur at higher altitude, in zones dominated by semi‐natural open habitats, and where cultivated area had decreased in the last 30 years. Between 1886 and 2001, rare species were the most prone to local extinction in zones where human population density, cultivated area and livestock density had increased the most. Between 1886 and 2001, rare species had a higher probability of local persistence in zones of high altitude and steep slope, on basic bedrocks and with low cultivated area. Rare species with Mountain and Eurosiberian affinities occurred in marginal habitats in the study region, i.e. on gneiss‐micaschist bedrocks and at high altitudes, whereas Mediterranean and South/Central European rare species occupied more varied environmental conditions. Between 1886 and 2001, Eurosiberian rare species showed high rates of local extinction whereas Mediterranean rare species had a significantly higher probability of local persistence. Restricted endemic species mostly occurred in zones of high slope, low human population density, and where cultivated area had decreased in the last 30 years. Occurrences of restricted endemics remained significantly stable between 1886 and 2001. Main conclusions Environmental and land‐use changes that occurred over the twentieth century in the Mediterranean Basin had significant impacts on the spatial distribution and on the long‐term dynamics of rare species occurrences. Urbanization and recent agriculture intensification, occurring mainly in coastal plains and littoral zones, caused most local extinctions of rare species from 1886 to 2001. Local populations of Eurosiberian species, which reach their range limits in marginal zones of the Mediterranean, also appear to be highly vulnerable. Conversely, most restricted endemic species occur in habitats with harsh topography and low human disturbance and have a higher potential of local persistence.     

Potamotrygon marquesi,a new species of neotropical freshwater stingray (Potamotrygonidae) from the Brazilian Amazon Basin

Potamotrygon marquesi, sp. nov., is described and compared with other species of Potamotrygon occurring in the Amazon Basin. The identity of this new species is supported by an extensive external and internal morphological study including coloration pattern, squamation, skeleton and ventral lateral-line canals. Morphometrics and meristics were used to further distinguish P. marquesi from congeners. Potamotrygon marquesi was first considered to fall within the range of variation found in P. motoro. However, even with an extensive variation in coloration observed in P. motoro, this new species presents a series of autapomorphies that confidently distinguishes it from what is understood as the morphological variation found in P. motoro. Additional morphological characters that diagnose P. marquesi include three angular cartilages, asymmetrical star-shaped denticles, a single regular row of spines on tail dorsum, lateral row of caudal spines near the sting insertion, dorsal disc background in beige and grey mixed with shades of grey and bearing open and closed bicolored rings, among others. Although presenting a gap of distribution along the west–east extension of the Amazon Basin, its diagnostic charactistics are consistent in both recorded regions. Our study supports the need for many morphological characters to robustly distinguish members of Potamotrygoninae considering their extremely variable dorsal disc color pattern.