Réflexions critiques sur l'écologieet la systématique des Lingules actuelles et fossiles

New topics on ecology and systematics of recent and fossil Lingulids lead to an obvious revision of our knowledges on this zoological group. At first, the recent species need systematics and taxonomy on the bases of new described specific criteria (as, morphology of deltidial areas, muscle disposition); the results are briefly indicated. But, in fossil species, disorder and disparity of used characteristics are emphasized.The general conceiving on ecology of Lingulids are reviewed and discussed, especially on bathymetry and salinity; sediment and oxygenation conditions; taphocoenosis and lingulid «communities. On recent species, all these points are also studied, especially some ecological requirements (salinity, bathymetry, grain size), and mechanism of burrowing ability, burrow living positions in the sediments, as shell preservations after death and fossilization, to facilitate the paleobiotope interpretations. Recent animals are euryhalin, surviving at salinities from about 13 to 42‰; they could be considered as well adapted to waters with strong salinity fluctuations. They show preference to fine sand bottoms (lowest particle size about 40–60 μm). Their bathymetric distribution occurs between 0 and about 500 m (Lingula especially between 5–50 m; Glottidia 15–70 m). The isotherms 8–10°C seem to restrict their geographical and bathymetric distribution.Therefore, some post-palaeozoic lingulid bedsare studied or redescribed on the bases of the above discussed characteristics, and new interpretations on the environmental situation are given (Trias of Vosges Mountains; Oligocene from Japan; Eocene of London Basin). More caution must be used in study of fossil Lingulids that are not especially animals living in infralittoral bottoms with low salinity and deficient oxygenation, as generally accepted.     

Palaeoecological evolution of Duckmantian wetlands in the Ruhr Basin (western Germany): A palynological and coal petrographical analysis

For this study, six seam sequences of Duckmantian age from the Ruhr Basin, western Germany, were analysed. 155 samples from drill cores were examined, including coal samples, as well as organic-rich and clastic sedimentary rocks. All samples were analysed using palynological and coal petrographical techniques. Based on published information of in situ miospores the encountered dispersed miospores were assigned to their parent plants in order to reconstruct the vegetation history. Six vegetational associations were identified using Detrended Correspondence Analyses (DCA): lepidocarpacean association I, lepidocarpacean association II, lepidocarpacean-sigillarian association, lepidocarpacean-sphenophyll association, lepidocarpacean-fern association, and the subarborescent lycopsid association.Lycospora is the most important constituent in the miospore association as in 75% of all samples the genus is represented with more than 50% relative abundance. Lepidocarpaceans such as Lepidophloios and Lepidodendron are very common among the plant fossils. Hence, arborescent lycopsids dominated the vegetation of the Ruhr Basin during the mid and late Duckmantian, forming flood plains and planar forest mires. Variations in the plant environment are reflected by greater influence of sigillarians, which were typical for swamp margins or for domed swamps, characterized by stunted vegetation. Fern-dominated environments were rare during the Duckmantian.A typical rhythmic succession shows an evolution from clastic flood plains through peat substrate planar mires, followed by a doming of the swamps and formation of ombrogenous mires. Floodplains reappeared during periods of subsidence, accompanied by a rise in water level.     

川西盆周丘陵地区油菜作物生态效应的初步探讨

名山县位于东经103°08′,北纬30°06′,是四川省商品粮油基地县之一,属川西盆周丘陵地区。年平均气温15.5℃,日照1052.0小时,降雨量1519.9mm,一年两熟,能满足油菜全生育期的需要。全县油菜发展较快,1989年较1983年种植面积扩大了33.91%,达到6000ha;总产增加30.35%,达到5958.1t。     

Discovery of the oldest known Pterygota in the Lower Carboniferous of the Upper Silesian Basin in the Czech Republic (Insecta: Archaeorthoptera)

The earliest pterygote (winged insect), dated from the Lower Carboniferous (Namurian A/E1, circa 324 millions years ago) is described from the Upper Silesian Basin in the Czech Republic. On the basis of its wing venation, it is attributed to the Archaeorthoptera Béthoux and Nel, 2002, crown group of the “Orthoptera”. Besides Apterygota (Collembola and Archaeognatha) known from the Lower Devonian, extremely rare pterygote insects are known from Lower Carboniferous deposits when they first appeared. The present discovery supports the hypothesis of the presence of the ancestor lineage of the orthopteroid in the Lower Carboniferous ecosystems.     

Stream hierarchy defines riverscape genetics of a North American desert fish

Global climate change is apparent within the Arctic and the south‐western deserts of North America, with record drought in the latter reflected within 640 000 km² of the Colorado River Basin. To discern the manner by which natural and anthropogenic drivers have compressed Basin‐wide fish biodiversity, and to establish a baseline for future climate effects, the Stream Hierarchy Model (SHM) was employed to juxtapose fluvial topography against molecular diversities of 1092 Bluehead Sucker (Catostomus discobolus). MtDNA revealed three geomorphically defined evolutionarily significant units (ESUs): Bonneville Basin, upper Little Colorado River and the remaining Colorado River Basin. Microsatellite analyses (16 loci) reinforced distinctiveness of the Bonneville Basin and upper Little Colorado River, but subdivided the Colorado River Basin into seven management units (MUs). One represents a cline of three admixed gene pools comprising the mainstem and its lower‐gradient tributaries. Six others are not only distinct genetically but also demographically (i.e. migrants/generation <9.7%). Two of these (i.e. Grand Canyon and Canyon de Chelly) are defined by geomorphology, two others (i.e. Fremont‐Muddy and San Raphael rivers) are isolated by sharp declivities as they drop precipitously from the west slope into the mainstem Colorado/Green rivers, another represents an isolated impoundment (i.e. Ringdahl Reservoir), while the last corresponds to a recognized subspecies (i.e. Zuni River, NM). Historical legacies of endemic fishes (ESUs) and their evolutionary potential (MUs) are clearly represented in our data, yet their arbiter will be the unrelenting natural and anthropogenic water depletions that will precipitate yet another conservation conflict within this unique but arid region.     

Century‐long apparent decrease in intrinsic water‐use efficiency with no evidence of progressive nutrient limitation in African tropical forests

Forests exhibit leaf‐ and ecosystem‐level responses to environmental changes. Specifically, rising carbon dioxide (CO₂) levels over the past century are expected to have increased the intrinsic water‐use efficiency (iWUE) of tropical trees while the ecosystem is gradually pushed into progressive nutrient limitation. Due to the long‐term character of these changes, however, observational datasets to validate both paradigms are limited in space and time. In this study, we used a unique herbarium record to go back nearly a century and show that despite the rise in CO₂ concentrations, iWUE has decreased in central African tropical trees in the Congo Basin. Although we find evidence that points to leaf‐level adaptation to increasing CO₂—that is, increasing photosynthesis‐related nutrients and decreasing maximum stomatal conductance, a decrease in leaf δ¹³C clearly indicates a decreasing iWUE over time. Additionally, the stoichiometric carbon to nitrogen and nitrogen to phosphorus ratios in the leaves show no sign of progressive nutrient limitation as they have remained constant since 1938, which suggests that nutrients have not increasingly limited productivity in this biome. Altogether, the data suggest that other environmental factors, such as increasing temperature, might have negatively affected net photosynthesis and consequently downregulated the iWUE. Results from this study reveal that the second largest tropical forest on Earth has responded differently to recent environmental changes than expected, highlighting the need for further on‐ground monitoring in the Congo Basin.     

广西百色盆地高岭坡遗址的地层及年代

广西百色盆地旧石器工业因含有众多的手斧且年代早到803 kaBP而闻名于世。盆地内发育有7级河流阶地,其中第IV级阶地发现有手斧和玻璃陨石。自从1973年第一个石器地点被发现,越来越多的遗址或地点被调查发现和发掘。以前研究认为,百色盆地旧石器只出自网纹红土层,年代均为803 kaBP。2013年以前,通常只在土状堆积的上部发掘,从来没有人对第IV级阶地的沉积物从地表到底部砾石层进行系统发掘,因此关于第IV级阶地的整体地层堆积情况及含石器层位很模糊。2013-2014年,广西文物保护与考古研究所会同田东县博物馆对百色盆地最重要的旧石器遗址之一——田东高岭坡遗址进行了系统的考古发掘。此次发掘从遗址的地表往下一直发掘到砾石层,揭露出厚度超过7m的完整地层序列,发现1处小型石器制造场和1处用火遗迹。在不同地层中发现石制品800多件,包括砍砸器、手镐、刮削器等。涵盖旧石器和新石器两个时代。根据地层对比和石制品的特征及测年结果,我们把旧石器时代文化遗存可分为3期：第一期的年代早于或等于803 kaBP,第二期为15 kaBP,第三期约为10 kaBP。     

Length-weight relationships of ornamental fish species from Amanã Lake,Amanã Reserve,Amazonas, Brazil

Length-weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish-traps (fyke-net like fish-traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.