Epilithic plant communities on inselbergs in French Guiana

Abstract. Tropical inselbergs are isolated elevations with a special type of vegetation and surrounded by rain forest. The paper describes, using the field methods of Braun-Blanquet, combined with numerical analysis (clustering, Correspondence Analysis), plant communities on French Guianan inselbergs. Six new associations are described: Portulacetum sedifolii, Furcraeetum foetidae, Ananasetum annassoidis, Stylosanthetum guianensis, Axonopetum ramosi and (endemic to the Guianan inselbergs) Pepinietum geyskesii – with three subassociations. The six vegetation units reflect different combinations of environmental factors such as local relief, insolation, water availability and soil depth. All syntaxa show a low species diversity. Species of Cyperaceae, Poaceae, Lentibulariaceae and Bromeliaceae are predominant, whereas families typical of other South American inselbergs (Velloziaceae and Cactaceae), are missing or scarce. Similarities between vegetation units of South American and African inselbergs are emphasized.     

The life and work of Rosemary Lowe-McConnell: pioneer in tropical fish ecology

Synopsis Rosemary Lowe-McConnell is one of the pioneers of tropical fish ecology. During a colourful and eventful career spanning over 45 years, she has worked in the tropical waters of Africa and South America and contributed significantly to our understanding of the ecology, zoogeography, phenology, evolution and taxonomy of tropical fishes. She has also assisted countless young ichthyologists and fisheries scientists and stimulated ichthyology through her lucid books on fish ecology. She continues to play an active role in the promotion of ichthyology and ecology from her home in Sussex in the English countryside. A brief biography and tribute is given so that her contributions to tropical fish ecology can be more widely appreciated.     

Revisiting marine redox conditions during the Ediacaran Shuram carbon isotope excursion

The Neoproterozoic carbonate record contains multiple carbon isotope anomalies, which are the subject of intense debate. The largest of these anomalies, the Shuram excursion (SE), occurred in the mid-Ediacaran (~574–567 Ma). Accurately reconstructing marine redox landscape is a clear path toward making sense of the mechanism that drives this δ¹³C anomaly. Here, we report new uranium isotopic data from the shallow-marine carbonates of the Wonoka Formation, Flinders Ranges, South Australia, where the SE is well preserved. Our data indicate that the δ²³⁸U trend during the SE is highly reproducible across globally disparate sections from different depositional settings. Previously, it was proposed that the positive shift of δ²³⁸U values during the SE suggests an extensive, near-modern level of marine oxygenation. However, recent publications suggest that the fractionation of uranium isotopes in ferruginous and anoxic conditions is comparable, opening up the possibility of non-unique interpretations of the carbonate uranium isotopic record. Here, we build on this idea by investigating the SE in conjunction with additional geochemical proxies. Using a revised uranium isotope mass balance model and an inverse stochastic carbon cycle model, we reevaluate models for δ¹³C and δ²³⁸U trends during the SE. We suggest that global seawater δ²³⁸U values during the SE could be explained by an expansion of ferruginous conditions and do not require a near-modern level of oxygenation during the mid-Ediacaran.     

NEW DISCOVERY OF YUNNANOLEPIDS- HETEROYUN-NANOLEPIS QUJINCENSIS (GEN. ET SP. NOV.)

Thenewformdiffersfromtlieotheryunnanolepidsinthefollowingcharacteristics:1)orbitalfenestrabiggerandinamoreanteriorposition;2)possessingpreorbitalrecess(prh)insteadofpreorbitaldepression;3)infraorbitalsensorycanalpassingthroughpostmarginalplate;supraorbitalsensorycanalonpost-pinealplate;4)posteriorinternaltransversecrestinamoreposteriorposition.Onthebasisofcharactersofthenewgenus,thefollowingconcludingremarksarepreliminarygiven:1)Thepreorbitaldepressioninyunnanolepidsisprobab1ynothomologouswith…     

2-Bromoacetamidopyridine: a new chemical probe of the active site of histidine decarboxylase from Lactobacillus 30a

In rats fasted for 24–30 hours, albumin mRNA sequences are released from membrane-bound polysomes to enter the free cytosol fraction. A significant portion of these sequences are present in albumin mRNPs, distinguished from free albumin mRNA and 40S subunit complexes by Cs₂SO₄ equilibrium density centrifugation. Refeeding a mixture of 20 amino acids restores albumin mRNA to membrane-bound polysomes, demonstrating the importance of amino acid supply in the mRNP-polysome equilibrium and in regulation of albumin synthesis.     

An early Indian cranium from the Medicine Crow site, (39BF2), Buffalo County,South Dakota

Artifacts of Paleoindians have been found in most if not all of the Plains states; however, documented human skeletal remains from this early period are rare. The Medicine Crow cranium dates by stratigraphy and by the amount of absorbed alpha and beta radiation at between 5,000 and 2,000 B.C. This places this young adult male in the Archaic period and represents the earliest documented human skeletal material from South Dakota. It compares favorably in age with other well documented human skeletons from the Plains area, such as Lansing Man (Kansas) (3579 B.C.). Metrically, (with a cranial index of 76.7) and morphologically the Medicine Crow cranium falls well within the range of other early or middle Archaic skeletons.     

Factors affecting depth distribution of dragonflies and other benthic insects in a thermally destabilized reservoir

The distribution and abundance of macroinvertebrates along a water depth gradient were studied in thermal and ambient temperature areas of a reservoir in the southeastern United States. Benthic samples were taken at 10 depths (0.16–5 m) during January–April, 1978. Factors affecting the depth distribution of Ceratopogonidae, Chaoboridae, Chironomidae, Ephemeroptera, Odonata, and Trichoptera are discussed. The relationship between abundance of organisms and water depth was more complex than an inverse relationship generally reported in the literature.     

A late Holocene climate record from a stalagmite, Cold Air Cave, Northern Province, South Africa

Stable isotope analyses of a uranium-series-dated stalagmite from South Africa provide a record of climate changes for the periods 4400–4000 years and 800 years ago to recent, interrupted by a prolonged growth hiatus. Generally enriched stable oxygen isotope values, interpreted here to indicate more humid conditions, occurred around 800 years ago. Subsequently a marked depletion in oxygen and carbon isotope values occurred about 600 years ago, reflecting, we believe, shifts toward drier, cooler conditions as the regional indication of the Little Ice Age. This period with depleted, yet oscillating isotope values, is replaced by a period with enriched isotopes until recent times. The record is notable for sharp shifts in isotopic values, on the scale of decades, which reflect rapid oscillations in local climate conditions.     

Distribution of Dacrydium in South China During the Late Quaternary

The pollen analysis of the Late Quaternary from South China, in particular, Yunnan and Guangdong provinces, made possible to restore the past distribution of Dacrydium in China. The chinese mainland flora today is totally devoid of Dacrydium. However, a single species (D. pierrei Hickel) is represented in the montane rainforests of Hainan Island (extreme south of China). The fossil pollen grains, morphologically comparable to that of D. pierrei, were discovered from the Tertiary and the Quaternary sediments in an extensive area of China. Even in the Last Interstadial of Wurm (40000–20000 Yr. B. P.), its distribution might extend to 22-24 degrees north latitude. The climatic deterioration and the environmental change during the Last Glacial (Late Wurm) had been a crucial factor when the flora of South China underwent drastic modification. It is in the same period that the present-day restriction of D. pierrei to Hainan Island took place.