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

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

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.

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.

scholarly journals Spatiotemporal Assessment of Land Marketization and Its Driving Forces for Sustainable Urban–Rural Development in Shaanxi Province in China

2021 ◽  
Vol 13 (14) ◽  
pp. 7755
Author(s):  
Xindong Wei ◽  
Ning Wang ◽  
Pingping Luo ◽  
Jie Yang ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Rural Development ◽  
Driving Forces ◽  
Hot Spot ◽  
Sustainable Use ◽  
Shaanxi Province ◽  
Use Of Resources ◽  
Gray Relation Analysis ◽  
Urban Rural ◽  
Northern Shaanxi ◽  
Southern Shaanxi

In recent years, market-oriented allocation of land has been promoted to support rural revitalization and urban–rural integrated development. To follow the path of sustainable development, it is necessary to improve the efficiency of resource utilization and to rationally allocate and use resources on the premise of ensuring the sustainable use of resources. This study aims to measure the degree of land marketization in Shaanxi Province, China during the period 2008–2019 and analyze its driving forces. The methods used include Gray Relation Analysis and Hot Spot Analysis. The MK trend method was used to analyze the average area of land acquired through Bidding–Listing–Auction (B-L-A), protocol, and allocation methods. The results show that the land marketization level in Shaanxi declined from 2008 to 2014 and fluctuated upwards from 2014 to 2019. In addition, B-L-A transactions increased across the province. There was little spatial heterogeneity of land marketization, but southern Shaanxi had less land marketization than the other key areas. Urbanization, non-agricultural output, and foreign direct investment were found to be the main driving factors of land marketization, while the influence of fixed asset investment and per capita disposable income declined each year. Based on these findings, we suggest that there is a need for land management reforms and urbanization efforts to encourage land marketization in southern Shaanxi. Further, we suggest that northern Shaanxi would benefit from optimizing the land use structure and focusing on the energy land market. This study also provides theoretical support for realizing the reform of the marketization of national land elements, the healthy operation of urban land marketization, and sustainable urban and rural development.

scholarly journals Coupling Coordination Analysis of Livelihood Efficiency and Land Use for Households in Poverty-Alleviated Mountainous Areas

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1115
Author(s):  
Fang Su ◽  
Jiangbo Chang ◽  
Haiyang Shang
Keyword(s):  
Land Use ◽  
Geographic Location ◽  
The Other ◽  
Shaanxi Province ◽  
Mountainous Area ◽  
Land Use Pattern ◽  
Land System ◽  
Medium Level ◽  
Southern Shaanxi ◽  
Coordination Degree

The interaction between livelihood means and land use pattern of households is the core of the interactive coupling of the human-land system. This study focuses on Qinba mountainous area in southern Shaanxi province, a typical poverty-alleviated mountainous area. With the help of the coupling coordination degree model, kernel density estimation, and trend surface analysis, this study constructs the coupling coordination degree of livelihood efficiency and land use for households, and analyzes the differences between households’ livelihood efficiency and land use level, as well as the coupling coordination relationship between households livelihood efficiency and land use in different types and regions. The research conclusions are as follows. (1) For households in the Qinba mountainous area, southern Shaanxi province, the livelihood efficiency is at a medium level of 0.681, the land use is at a low level of 0.127, while the coupling coordination degree 0.526 is at the primary coordination state. (2) With the increase of nonagricultural degree, the coupling coordination degree of households increases first, and then decreases. (3) The coupling coordination degree for households east-to-west is “sagging”, while south-to-north diagram is “hogging”. (4) The distribution of the coupling coordination degree for agriculture-dependent households east-to-west (the “sagging” diagram) is opposite to the other types of households. By analogy, the distribution of the coupling coordination degree for nonagriculture and agriculture-dependent households north-to-south (the “hogging” diagram) is opposite to the other types of households. The coupling coordination between the households’ livelihood efficiency and land use level is affected by the households’ regional development level, natural resources, geographic location, infrastructure availability and many other factors. Making appropriate livelihood development plans based on the types of households and regional space can both effectively improve the livelihood conditions, as well as offer guidance in promoting regional human-land activity coordination and ensuring sustainable development.

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