New bradoriids from the Lower Cambrian Yanwangbian formation of southern Shaanxi Province, Central China

Palaeoworld ◽  
2008 ◽  
Vol 17 (2) ◽  
pp. 102-107 ◽  
Author(s):  
Yu Liu ◽  
Xing-Liang Zhang ◽  
Wei Liu ◽  
Qian Zhang
Keyword(s):  
Lower Cambrian ◽  
Central China ◽  
Shaanxi Province ◽  
Southern Shaanxi

Occurrence of the earliest known Sphenothallus Hall in the Lower Cambrian of Southern Shaanxi Province, China

Geobios ◽  
2004 ◽  
Vol 37 (2) ◽  
pp. 229-237 ◽  
Author(s):  
Guo-Xiang Li ◽  
Mao-Yan Zhu ◽  
Heyo Van Iten ◽  
Chia-Wei Li
Keyword(s):  
Lower Cambrian ◽  
Shaanxi Province ◽  
Southern Shaanxi

scholarly journals Assessment of Soil Erosion in the Qinba Mountains of the Southern Shaanxi Province in China Using the RUSLE Model

2020 ◽  
Vol 12 (5) ◽  
pp. 1733 ◽  
Author(s):  
Zhijie Wang ◽  
Yuan Su
Keyword(s):  
Soil Erosion ◽  
Water Source ◽  
Central China ◽  
Water Diversion ◽  
Shaanxi Province ◽  
Ecological Security ◽  
Rusle Model ◽  
Southern Shaanxi ◽  
Regional Ecological Security

The Southern Shaanxi Province, an important ecological security barrier area in central China, is the primary water source of the south-to-north water transfer project in China. However, severe soil erosion seriously affects the safety of regional ecological security and water quality of the water diversion project. To reveal the characteristics and variation of soil erosion in the southern Shaanxi Province after the implementation of a series of eco-environmental construction measures, in this study, the spatio-temporal characteristics of soil erosion from 2000 to 2014 were evaluated based on the Revised Universal Soil Loss Equation (RUSLE) model and Geographic Information Systems (GIS). The average soil erosion of southern Shaanxi Province in China was characterized as slight (less than 500 t·km–2·a–1) and mild erosion (500–2500 t·km–2·a–1) with an average soil erosion modulus of 1443.49 t·km–2·a–1, 1710.49 t·km–2·a–1, 1771.99 t·km–2·a–1 and 1647.74 t·km–2·a–1 in 2000, 2005, 2010 and 2014, respectively. The results revealed an increase in soil erosion until 2000 and a mitigation during the period of 2000 to 2014. After 2010, the soil erosion was controlled effectively. The spatial distribution of soil erosion displayed obvious spatial heterogeneity, and the high soil erosion (greater than 2500 t·km–2·a–1) was primarily distributed in the north-central and south counties of the study area. The soil erosion remained high and aggravated in six counties (i.e., Zhen’an, Zhashui, Ningshan, Ningqiang, Lueyang and Shanyang), and high erosion (greater than 5000 t·km–2·a–1) was found in the regions with slope gradients greater than 35 degrees and the middle mountainous (800–2000 m) regions. Therefore, the eco-environmental construction measures could effectively control soil erosion. However, unreasonable human activities remain the primary cause of soil erosion in the southern Shaanxi Province. In the future, more comprehensive and thorough ecological construction measures will be necessary to ensure regional ecological security and the eco-environmental quality of water sources.

Cambrothyra ampulliformis, an unusual coeloscleritophoran from the Lower Cambrian of Shaanxi Province, China

2010 ◽  
Vol 84 (6) ◽  
pp. 1040-1060 ◽  
Author(s):  
John L. Moore ◽  
Susannah M. Porter ◽  
Michael Steiner ◽  
Guoxiang Li
Keyword(s):  
Lower Cambrian ◽  
Mirror Image ◽  
Shaanxi Province ◽  
Large Collection ◽  
Natural Group ◽  
Dengying Formation ◽  
Southern Shaanxi ◽  
Image Pairs ◽  
Multiple Species

Cambrothyra ampulliformis Qian and Zhang, 1983, is a jar- or vase-shaped fossil known from the Lower Cambrian of Shaanxi and Hubei provinces, China. It has been interpreted as a protistan test or cyst or a metazoan sclerite. A large collection of specimens from the Xihaoping Member of the Dengying Formation in southern Shaanxi Province permits its detailed redescription. These fossils are highly variable in shape but this variation is continuous and does not support the current recognition of multiple species for this material. They were originally hollow with a restricted basal foramen and a calcareous wall probably composed of fibrous aragonite. All of these features support the identification of Cambrothyra as sclerites of a coeloscleritophoran, a problematic group of Cambrian scleritome-bearing metazoans. Furthermore, the walls of Cambrothyra sclerites contain numerous pores, a feature shared with other coeloscleritophorans. Cambrothyra resembles chancelloriids in particular due to the shared presence of a verruculose texture around the foramen and the absence of mirror-image pairs of asymmetric sclerites. However, unlike chancelloriids, which have rosette-like compound sclerites, the scleritome of Cambrothyra was dominated by isolated sclerites, with only a few pairs and clusters of sclerites and twin sclerites. Consequently, we hypothesize that Cambrothyra forms a clade with other chancelloriids, but represents a basal lineage that plesiomorphically retained isolated sclerites. The morphology of Cambrothyra sclerites, which shares features with both chancelloriids and halkieriids, thus supports the hypothesis that all coeloscleritophorans form a natural group.

scholarly journals Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuanxing Ye ◽  
Canshi Hu ◽  
Yiting Jiang ◽  
Geoffrey W. H. Davison ◽  
Changqing Ding
Keyword(s):  
Niche Partitioning ◽  
Trophic Niche ◽  
Egg Laying ◽  
Central China ◽  
Paddy Fields ◽  
Shaanxi Province ◽  
Similar Species ◽  
Wetland Birds ◽  
Cattle Egret ◽  
River Banks

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.

Occurrence of the Enigmatic Bivalved FossilApistoconchain the Lower Cambrian of Southeast Shaanxi, North China Platform

2014 ◽  
Vol 88 (2) ◽  
pp. 359-366 ◽  
Author(s):  
Guoxiang Li ◽  
Zhifei Zhang ◽  
Hong Hua ◽  
Huining Yang
Keyword(s):  
Carbonate Rocks ◽  
Lower Cambrian ◽  
Morphological Analysis ◽  
North China ◽  
Bilateral Symmetry ◽  
Shaanxi Province ◽  
Single Type ◽  
Posterior Teeth ◽  
North China Platform ◽  
Stem Group

The early Cambrian calcareous skeletal fossilApistoconchaConway Morris is characterized by its two valves having posterior teeth and internal umbonal cavities. It has been reported from lower Cambrian Botomian-equivalent carbonate rocks in Australia, Mongolia, and Greenland. Here we report a new occurrence ofApistoconchain the lower Cambrian Xinji Formation of Luonan, southeast Shaanxi Province, North China Platform. Based on material (five ventral and four dorsal valves) from the Xinji Formation,Apistoconchacf.aphelesis systematically described and the taxonomic affinity ofApistoconchais discussed. The shell ofApistoconchapossesses an ‘antero-posterior’ plane of bilateral symmetry, and its two valves apparently articulated in life, although the tooth-like structures and pits show little resemblance to the teeth and sockets, respectively, of bivalved shells of rhynchonelliform brachiopods or pelecypods.Apistoconchacannot be assigned to the crown groups of either brachiopods or mollusks, even though functional morphological analysis indicates thatApistoconchamay be a ‘stem-group brachiopod’. UnlikeApistoconcha, the morphologically similarTianzhushanellaLiu is known only from a single type of valve lacking posterior teeth and pits.Tianzhushanellamay represent either a univalved animal or a bivalved animal, the other valve of which has not yet been identified. Even though bothApistoconchaandTianzhushanellamay represent stem-group brachiopods, they probably correspond to different stages of brachiopod evolution. Thus assignment ofApistoconchaandTianzhushanellato the same family (Tianzhushanellidae) may obscure their phylogenic implications.

ACloudina-like fossil with evidence of asexual reproduction from the lowest Cambrian, South China

2017 ◽  
Vol 154 (6) ◽  
pp. 1294-1305 ◽  
Author(s):  
JIAN HAN ◽  
YAOPING CAI ◽  
JAMES D. SCHIFFBAUER ◽  
HONG HUA ◽  
XING WANG ◽  
...  
Keyword(s):  
Asexual Reproduction ◽  
South China ◽  
Fossil Record ◽  
Tube Wall ◽  
Shaanxi Province ◽  
Branching Structures ◽  
Southern Shaanxi ◽  
Wall Construction ◽  
Evolutionary Continuity ◽  
Evolutionary Fate

AbstractThe earliest fossil record of animal biomineralization occurs in the latest Ediacaran Period (c. 550 Ma).CloudinaandSinotubulitesare two important tubular taxa among these earliest skeletal fossils. The evolutionary fate ofCloudina-type fossils across the Ediacaran–Cambrian transition, however, remains poorly understood. Here we report a multi-layered tubular microfossilFeiyanella manicagen. et sp. nov. from a phosphorite interval of the lowest Cambrian Kuanchuanpu Formation, southern Shaanxi Province, South China. This newly discovered fossil is a conical tube with a ‘funnel-in-funnel’ construction, showing profound morphological similarities toCloudinaandConotubus. On the other hand, the outer few layers, and particularly the outermost layer, ofFeiyanellatubes are regularly to irregularly corrugated, a feature strikingly similar to the variably folded/wrinkled tube walls ofSinotubulites. TheFeiyanellatubes additionally exhibit two orders of dichotomous branching, similar to branching structures reported occasionally inCloudinaand possibly indicative of asexual reproduction. Owing to broad similarities in tube morphology, tube wall construction and features presumably indicative of asexual reproduction,Cloudina, Conotubus, Sinotubulitesand the here describedFeiyanellamay thus constitute a monophyletic group traversing the Ediacaran–Cambrian boundary. The tube construction and palaeoecological strategy ofFeiyanellaputatively indicate evolutionary continuity in morphology and palaeoecology of benthic metazoan communities across the Ediacaran–Cambrian transition.

scholarly journals Changes in the epidemiological characteristics of human brucellosis in Shaanxi Province from 2008 to 2020

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cui-hong An ◽  
Zhi-guo Liu ◽  
Shou-min Nie ◽  
Yang-xin Sun ◽  
Suo-ping Fan ◽  
...  
Keyword(s):  
Incidence Rate ◽  
Large Scale ◽  
Small Ruminants ◽  
Raw Milk ◽  
Shaanxi Province ◽  
Significant Feature ◽  
Human Brucellosis ◽  
Northern Shaanxi ◽  
Southern Shaanxi ◽  
Epidemiological Characteristics

AbstractIn the present study, surveys of case numbers, constituent ratios, conventional biotyping, and multilocus sequence typing (MLST) were applied to characterize the incidence rate and epidemiological characteristics of human brucellosis in Shaanxi Province, China. A total of 12,215 human brucellosis cases were reported during 2008–2020, for an annual average incidence rate of 2.48/100,000. The most significant change was that the county numbers of reported cases increased from 36 in 2008 to 84 in 2020, with a geographic expansion trend from northern Shaanxi to Guanzhong, and southern Shaanxi regions; the incidence rate declined in previous epidemic northern Shaanxi regions while increasing each year in Guanzhong and southern Shaanxi regions such as Hancheng and Xianyang. The increased incidence was closely related to the development of large-scale small ruminants (goats and sheep) farms in Guanzhong and some southern Shaanxi regions. Another significant feature was that student cases (n = 261) were ranked second among all occupations, accounting for 2.14% of the total number of cases, with the majority due to drinking unsterilized goat milk. Three Brucella species were detected (B. melitensis (bv. 1, 2, 3 and variant), B. abortus bv. 3/6, and B. suis bv. 1) and were mainly distributed in the northern Shaanxi and Guanzhong regions. Three known STs (ST8, ST2, and ST14) were identified based on MLST analysis. The characteristics that had not changed were that B. melitensis strains belonging to the ST8 population were the dominant species and were observed in all nine regions during the examined periods. Strengthened human and animal brucellosis surveillance and restriction of the transfer of infected sheep (goats) as well as students avoiding drinking raw milk are suggested as optimal control strategies.

Lower Cambrian coeloscleritophorans (Ninella, Siphogonuchites) from Xinjiang and Shaanxi, China

1996 ◽  
Vol 133 (1) ◽  
pp. 33-51 ◽  
Author(s):  
S. Conway Morris ◽  
A. J. Chapman
Keyword(s):  
Lower Cambrian ◽  
Lower Surface ◽  
Shaanxi Province

AbstractNinella tarimensis from the Lower Cambrian Yurtus Formation of western Xinjiang, China, is shown to be a relative of the halkieriids and siphogonuchitids. These are known principally from dispersed sclerites, presumably secreted by slug-like organisms that were an abundant component of the Cambrian benthos. The sclerites of N. tarimensis are relatively small, strongly recurved and usually possess an upper surface ornamented with transverse sculpture. The lower surface is more or less smooth and is joined to the upper surface via steep faces that may be grooved. The apertural region is quadrate in outline and bears a circular foramen. Ninella is fairly widespread and is known from elsewhere in China (Guizhou and Shaanxi Provinces) and from Kazakhstan. A brief description of the siphogonuchitid scleritome is also presented, based on dispersed sclerites and shells from the Lower Cambrian of Shaanxi Province, China. Formal synonymy of the sciotaxa Siphogonuchites, Dabashanites, Lopochites, and Maikhanella as Siphogonuchites is proposed.

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