A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China

Captorhinids, a clade of Paleozoic reptiles, are represented by a rich fossil record that extends from the Late Carboniferous into the Late Permian. Representatives of this clade dispersed from the equatorial regions of Laurasia into the temperate regions of Pangea during the Middle and Late Permian. This rich fossil record shows that there was an evolutionary trend from faunivorous to omnivorous and herbivorous feeding habits within this clade. The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp. nov, is a member of Moradisaurinae, a clade of captorhinids with multiple tooth rows arranged in parallel. The presence of this moradisaurine in the Middle Permian of south central Asia leads us to suggest that paleogeographic changes during the Permian, with part of what is today China becoming a large peninsula of Pangea, allowed these early reptiles as well as other terrestrial vertebrates to extend their geographic ranges to this region of the Late Paleozoic supercontinent.     

A new bolosaurid parareptile, Belebey chengi sp. nov., from the Middle Permian of China and its paleogeographic significance

A new bolosaurid parareptile, Belebey chengi sp. nov., is described from Dashankou, Gansu Province, China, a Middle Permian locality which is known mostly for its therapsid fauna. The material consists of well-preserved mandibular and anterior skull remains and currently represents the largest and latest surviving member of Bolosauridae. Phylogenetic analysis of bolosaurid interrelationships, the first analysis of any clade of Early Permian parareptiles, indicates that the new taxon groups consistently with the other (Russian) members of the genus Belebey, and forms the sister clade to the genus Bolosaurus from North America. The Early Permian Eudibamus cursoris from Germany falls into the basal most position within Bolosauridae. Our analysis also shows that the split between the main bolosaurid lineages must have occurred near or before the Permo-Carboniferous boundary and that the paleo-equatorial region of Laurasia probably served as the center of origination for these parareptiles. A similar pattern can be found in other clades of Paleozoic amniotes, suggesting that this may be the general trend in early amniote evolution.     

南京市大气沉降中重金属特征及对土壤环境的影响

为明确城市大气重金属沉降对土壤环境的影响,在对南京市6个典型城市功能区连续4a大气(干、湿)沉降中重金属(Cu、Zn、Pb、Cr、Ni)含量、通量、时空变异等方面研究的基础上,结合不同功能区表土重金属含量与土壤剖面206Pb/207Pb特征,分析其在城市土壤的累积特征.研究显示,Cu、Zn和Pb在大气沉降中强烈富集,其中又以Cu和Pb为潜在生态危害的关键元素.大气沉降导致除在相对未受城市人为活动影响的风景区外各功能区表土重金属均有明显富集,这种富集受大气沉降重金属含量和沉降量的共同影响.土壤累积模式预测钢铁工业区表土受大气重金属沉降影响的长期累积增量最大,以Zn和Pb最明显.钢铁工业区土壤剖面Pb含量和同位素特征显示表层20cm土体受大气沉降影响明显,206Pb/207Pb二元模型与预测模式对定量大气Pb沉降的土壤影响结果较一致,表明土壤中某些重金属的累积与大气沉降密切相关.     

Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed

Environmental Science and Pollution Research - Nitrate (NO3?) loss and enrichment in water bodies caused by fertilization are a major environmental problem in agricultural areas. However, the...     

Responses of photosynthesis,antioxidant enzymes,and related gene expression to nicosulfuron stress in sweet maize (Zea mays L.)

Environmental Science and Pollution Research - Weed control in maize (Zea mays L.) crops is usually undertaken using the postemergence herbicide nicosulfuron. The toxicity of nicosulfuron on maize,...     

Historical change of heavy metals in urban soils of Nanjing, China during the past 20 centuries

Two typical areas, including once commercial and residential quarters of Nanjing, China, were studied by investigating soil properties especially heavy metals of soils in various cultural layers formed in different Chinese Dynasties. The age of the soil profiles was dated by both archaeological and 14C chronological methods. The results showed that urban soils in the old commercial/workshop quarter of Nanjing were generally contaminated by heavy metals Cu, Zn, Pb, but their concentration levels varied significantly among the cultural layers formed in different dynasties. The substantial increase of heavy metals appeared in three historical periods, i.e., South Dynasty (222-589 AD), the earlier Ming (1368-1644 AD) and the late Qing (1644-1912 AD) in one area. The tremendous input and storage of heavy metals in soils was explained by the primitive smelting and the strengthened metal processing activities, which might be due to the requirement of weapon making or other industries, in the changing social conditions of the corresponding periods. Soils in the once noble political, cultural centers did not show significant increase of heavy metals. The difference in the distribution pattern of heavy metals revealed the contrasting history of the site uses. The change of contaminant level in soils is believed to be a reflection of various human activities in the city during the past 20 centuries.