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1.
Here we report an artiodactyl trackway from Musandam Peninsula, Sultanate of Oman. Epireliefs of the tracks are preserved in poorly consolidated aeolian deposits now making up the ceiling of a coastal cave. As an interesting morphological feature, the trackway documents the trackmaker negotiating a slippery dune slope at an angle.  相似文献   

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Paleoecology of a large Early Cambrian bioturbator   总被引:1,自引:0,他引:1  
The Lower Cambrian Poleta Formation in the White-Inyo Mountains of eastern California contains well-preserved and laterally extensive exposures of the large looping and meandering trace fossil Taphrhelminthopsis nelsoni n.isp. Such traces are typical features on upper bed surfaces of Lower Cambrian shallow marine sandstones and occur with Ediacaran fossils at other localities. Morphologic, sedimentologic and goniogram analyses suggest that the inferred tracemaker was a large soft-bodied echinozoan- or mollusc-grade animal with a volume greater than 14 cm3 that actively grazed or ingested sediment at the sediment-water interface. Although portions of these traces appear to reflect relatively 'complex' behavior, looping patterns are not periodic as expected for a systematic foraging strategy. T. nelsoni traces are patchy in distribution and commonly associated with suspect-microbial features, suggesting that tracemakers may have been targeting microbial-based or related concentrations of food resources. Such behavioral patterns are typical of shallow late Neoproterozoic-early Cambrian settings, and like suspect-microbial structures are later restricted to deep marine or stressed settings.  相似文献   

4.
Fungi and aflatoxins associated with spices in the Sultanate of Oman   总被引:3,自引:1,他引:3  
One hundred and five samples of seven spices (cumin, cinnamon, clove, black pepper, cardamom, ginger, and coriander) were purchased from five popular companies in the Sultanate of Oman. The spices were surveyed for the mycoflora and aflatoxins. Twenty fungal species were isolated in which Aspergillus flavus , A. niger . Penicillium , Rhizopus , and Syncephalastrum racemosum were the most dominant. When colony forming units per gm (cfu/gm) of fungi were compared, significant differences were found among spices and companies. Of the seven spices studied, clove was found to be the least contaminated, while cumin was the most contaminated. None of the 15 selected samples of the spices contaminated by A. flavus were found to contain aflatoxins. Nevertheless, nine isolates (45%) of the twenty A. flavus strains screened for aflatoxins were aflatoxigenic. The moisture content of most of the spices was below the maximum standard limit. The results showed that the spices were contaminated by some fungi that might constitute health hazards for humans. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

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Gerd Geyer   《Palaeoworld》2006,15(3-4):348
Oryctocephalid trilobites from Lower Middle Cambrian strata of the eastern Anti-Atlas, Morocco, are the first described Oryctocephalidae known from Africa. They represent the new genus and species Shergoldiella vincenti. However, a similar species was earlier described as Tonkinella sequei Liñán et Gozalo, 1999, from coeval lower Middle Cambrian strata of the Iberian Chains, northern Spain. This Iberian species is imperfectly preserved and assigned herein to Shergoldiella with reservations. If this assignment is correct, it would reinforce earlier suggested correlations between Morocco and Spain. Nevertheless, Shergoldiella suggests a morphocline from a typical oryctocephalid-type morphology towards the Tonkinella-type morphology. Close similarity with Ovatoryctocara ovata suggests a similar stratigraphic position in accordance with earlier suggested intercontinental correlations.  相似文献   

6.
The largest recorded carbon isotopic excursion in Earth history is observed globally in carbonate rocks of middle Ediacaran age. Known from the Sultanate of Oman as the ‘Shuram excursion’, this event records a dramatic, systematic shift in δ13Ccarbonate values to ca. ?12‰. Attempts to explain the nature, magnitude and origin of this excursion include (i) a primary signal resulting from the protracted oxidation of a large dissolved organic carbon reservoir in seawater, release of methane from sediment‐hosted clathrates, or water column stratification; and (ii) a secondary signal from diagenetic processes. The compositions and isotope ratios of organic carbon phases during the excursion are critical to evaluating these ideas; however, previous work has focused on localities that are low in organic carbon, hindering straightforward interpretation of the observed time‐series trends. We report carbon isotope data from bulk organic carbon, extracted bitumen and kerogen, in addition to lipid biomarker data, from a subsurface well drilled on the eastern flank of the South Oman Salt Basin, Sultanate of Oman. This section captures Nafun Group strata through the Ediacaran–Cambrian boundary in the Ara Group and includes an organic‐rich, deeper‐water facies of the Shuram Formation. Despite the high organic matter contents, the carbon isotopic compositions of carbonates – which record a negative δ13C isotope excursion similar in shape and magnitude to sections elsewhere in Oman – do not covary with those of organic phases (bulk TOC, bitumen and kerogen). Paired inorganic and organic δ13C data only display coupled behaviour during the latter part of the excursion's recovery. Furthermore, lipid biomarker data reveal that organic matter composition and source inputs varied stratigraphically, reflecting biological community shifts in non‐migrated, syngenetic organic matter deposited during this interval.  相似文献   

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Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined.  相似文献   

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Decomposition of Juglans regia leaves was studied in fine and coarse mesh bags in a permanent mountain stream in Oman. A rapid initial mass loss, attributed to leaching, was followed by a more gradual decline. Daily exponential decay rates (k) calculated over 32 days were 0.011 (fine mesh litter bags) and 0.014 (coarse mesh litter bags). The difference between bag types was not significant, suggesting limited impact of leaf‐shredding invertebrates. Ergosterol levels on leaves from fine mesh bags peaked at 0.3 mg g1 AFDM after 16 days of stream exposure. During the experimental period, which followed the annual leaf fall, the concentration of aquatic hyphomycete conidia in the stream varied between 82 and 1362 l–1. Based on the morphology of conidia found in the water column or released from leaves, we identified 14 species of aquatic hyphomycetes. Tetracladium apiense was the most common taxon (62.2% of conidia in water column during the field experiment). Three other Tetracladium species contributed another 8%. Plating out leaf particles yielded common epiphytic taxa such as Alternaria sp., Aureobasidium pullulans and Phoma sp. The measured metrics of leaf decay in this desert stream fall within the range of values observed in temperate and tropical streams, with clear evidence for an early leaching phase, and no evidence of a strong impact of leaf shredders. The community of aquatic hyphomycetes appears impoverished. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

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Fungi associated with black tea and tea quality in the Sultanate of Oman   总被引:3,自引:0,他引:3  
Forty-eight samples of four popular commercial brands of black tea ( Camellia sinensis L.) were purchased from the local markets in Muscat area, Sultanate of Oman. Tea leaves were surveyed for mycoflora. Five fungal species were isolated with A. niger as the most dominant in all the brands having percentage contamination ranging between 0.66% and 30.34%. Other fungi isolated were Aspergillus flavus, Penicillium spp. and Pacelomyces spp. but having average percentages of 0.6%, 0.84% and 0.21% respectively. Significant differences were found among the batches contaminated by A. niger. None of the 25 A. flavus strains screened for aflatoxins were found aflatoxigenic. The total ash, water-soluble ash, and mineral concentration of the samples were within the British standards and were not affected by fungal contamination. The results showed that black tea is contaminated by fungi that might constitute health hazards for humans. The post harvest contamination of tea could be eliminated or reduced if processing is conducted under more hygienic conditions. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

11.
The spawning periods, sex ratio and length at first maturity were determined for six commercially important finfish species collected from Oman's industrial trawl fishery. During 1 year of monthly sampling, biological data were collected on 5586 fish. ancova was used to compare the length–weight relationships between sexes. There were sex‐specific differences in length‐weight relationships for three of the six species examined. One serranid, Epinephelus diacanthus, and a sparid, Pagellus affinis, had sex ratios significantly different from the expected ratio of 1 : 1. Size–frequency data revealed more male fish in the larger size classes for E. diacanthus, P. affinis and Nemipterus japonicus. Data on the development of female gonads and Gonado‐somatic Index (GSI) revealed that the six species spawned at different times of the year. With the exception of female E. diacanthus, all fish had low GSI values during the onset of the summer monsoon period in June. The proportion of immature vs mature fish in the sample differed among species. For two species, Lethrinus nebulosus and Cheimerius nufar, more than 40% of the fish sampled (both sexes) were immature. Approximately 33% female and 41% male P. affinis were also immature. Management options such as temporal and area closures are discussed in light of the large number of immature fish caught by the fishery.  相似文献   

12.
Muscat Governorate in the Sultanate of Oman is located along the sea of Oman and urban development has therefore had to occur in the intervening flat coastal plains and valleys along the coastline. The physical location of Muscat Governorate exposes the city to heavy rain and cyclones as they hit the coastline from the Sea of Oman. This underlying exposure plays a major role in the risk processes that lead to the emphasis of particular climate change risks including storm surge and rain-related flooding as experienced during Gonu Cyclone in 2007 and Phet Cyclone in 2010. For assessing flooding risk analysis, this study combined flooding hazard maps with major land use cover to quantify and validate the risks of flash flooding to urban area and infrastructures. Analysis identified substantial areas within the governorate exposure to high, medium, and low risks from extreme rainfall events that could lead to direct damages to roads, buildings, and other properties. This reinforces the need to protect and strengthen current defenses against these events as well as greater preparedness in disaster response.  相似文献   

13.
Autism spectrum disorder (ASD) is a neurodevelopmental disorder of early childhood, and an enumeration about its etiology and consequences is still limited. Oxidative stress-induced mechanisms are believed to be the major cause for ASD. In this study 19 autistic and 19 age-matched normal Omani children were recruited to analyze their degree of redox status and a prewritten consent was obtained. Blood was withdrawn from subjects in heparin-coated tube, and plasma was separated. Plasma oxidative stress indicators such as nitric oxide (NO), malondialdehyde (MDA), protein carbonyl, and lactate to pyruvate ratio were quantified using commercially available kits. A significant elevation was observed in the levels of NO, MDA, protein carbonyl, and lactate to pyruvate ratio in the plasma of Omani autistic children as compared to their age-matched controls. These oxidative stress markers are strongly associated with major cellular injury and manifest severe mitochondrial dysfunction in autistic pathology. Our results also suggest that oxidative stress might be involved in the pathogenesis of ASD, and these parameters could be considered as diagnostic markers to ensure the prevalence of ASD in Omani children. However, the oxidative stress-induced molecular mechanisms in ASD should be studied in detail.  相似文献   

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SUMMARY. Aphanius dispar was observed in the field and some simple laboratory studies were undertaken in Oman. A. dispar is almost totally ubiquitous in all bodies of fresh water where it occupies a wide range of habitats differing in stream flow, water chemistry, temperature and substrate quality. It often is found in association with one or both of two cyprinid fishes. Cyprinion and Garra. Aphanius is tolerant of wide ranges of salinity up to full marine water and has a wide temperature range. A. dispar resembles Cyprinodon species in a number of particulars, probably reflecting phylogenetic relationships and a common evolutionary response to desert conditions. It breeds throughout the year with a probable peak in the months of April to June.  相似文献   

16.
Wynne  M. J. 《Journal of phycology》2003,39(S1):60-61
Intensive littoral and sublittoral collecting on the monsoon-impacted rocky shores of southern Oman, made at the end of the summertime monsoon (Sept. 2000 and Sept. 2001), has produced a remarkably high number of undescribed taxa and new records for this region of the Northern Arabian Sea. Taxa to be discussed in this presentation include: a new species of Centroceras that reaches 60 cm in height, is heavily corticated, has distinctively secund branching, and occurs well into the 'supralittoral fringe'; a new species of Jolyna , which is often branched, is not as long or thick as the more common J. laminarioides , has ascocysts but lacks hair tufts, and also occurs in the supralittoral; a Turbinaria (T. foliosa) that has the least modified blades known in the genus; a remarkably robust and erect species of Leveillea ; and an undescribed Gelidium , which has previously passed under the name of ' Suhria vittata '. A complicated picture has emerged that shows this flora to have biogeographical affinities with pantropical and subtropical regions, the tropical-subtropical Indo-Pacific, South Africa, temperate Europe and the Mediterrranean, Japan, as well as revealing components that are characteristic of the Arabian Sea monsoon season and apparent endemics restricted to Oman. This research (the Algal Biodiversity Project of Oman) has been funded by the British Government's Darwin's Initiative grant for the 'Survival of Species' and managed by HTS Development, Ltd., of the U.K.  相似文献   

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In a section from the central Oman Mountains (Wahrah Formation, Jebel Buwaydah) well preserved radiolarians were extracted. Stratigraphically they represent typical earliest Cretaceous species (Bernasian). Besides well known Tethyan species allowing an exact age determination, unknown morphotypes are common in some samples. Some of these represent new species, which are described herein. The composition and diversity of the faunas hints to a depositional environment in the lower bathyal.  相似文献   

19.
《Marine Micropaleontology》2011,81(3-4):62-73
The identification of tsunami and storm deposits in arid coastal environments can be problematic, as overwash sediments may not show significant contrasting lithologic characters with lagoonal sediments. In this study foraminifera were evaluated as an overwash indicator in a small (12 km2) intertidal lagoon located at Sur, in the Sultanate of Oman. The lagoon is shallow (< 5 m depth), tidally-controlled and communicates with the open sea through a narrow subtidal entrance channel. The lagoon is largely composed of intertidal sand and mudflats with fringing mangroves. Previous work at Sur identified evidence for overwash deposits associated with the 28 November 1945 Makran Trench tsunami (Mw 8.1) which were identified based on the presence of a laterally extensive shelly bed with distinctive taphonomic characters. In this study, particle size, stable isotopic and foraminiferal (taxa and taphonomy) analyses were conducted on surface sediment samples from Sur Lagoon to determine modern spatial trends in the lagoon for future comparison with overwash sediments deeper in the geologic record. Q-mode cluster analysis of the foraminiferal data (n = 54) found three main biofacies which follow lagoon sub-environments: Shallow Marine Area, Main Lagoon Basin, and Distal Lagoon Basin. The Shallow Marine Area is mainly subtidal with higher wave energy, the Main Lagoon Basin is predominantly intertidal with moderate wave energy, whereas the Distal Lagoon Basin is isolated and mainly intertidal with low wave energy.The most useful parameters for assessing overwash events in Sur Lagoon are the foraminifera taxa rather than the taphonomic characters themselves. The most useful taxa for recognizing an overwash (e.g. tsunami or storm) will be the abundance of Amphistegina spp., Ammonia inflata, Elphidium advenum and planktics which are predominantly found in the Shallow Marine Area. The abundance trend of these species with distance into the lagoon has an inverse relationship with higher r2 values than the other taxa. Taphonomically there is a predominance of larger specimens in the Shallow Marine Area along with a higher abundance of fossil specimens.  相似文献   

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