SEM analysis of trunk ornamentation on a compressed palaeoscolecid fossil from the Shipai fauna, Cambrian Series 2 and Stage 4 at Three Gorges, South China, allows a reassignment of the material to a new taxon, Sanxia...SEM analysis of trunk ornamentation on a compressed palaeoscolecid fossil from the Shipai fauna, Cambrian Series 2 and Stage 4 at Three Gorges, South China, allows a reassignment of the material to a new taxon, Sanxiascolex papillogyrus gen. et sp. nov. The preserved body is entirely annulated. Each annulus is ornamented by four rows of irregularly alternating plates and each plate bears numerous tubercles at the marginal region and a variable number （zero to six） of nodes at its central part. These features are unique among known palaeoscolecids. Comparative analyses with other compressed palaeoscolecid macrofossils and phosphatized material on the pattern of trunk ornamentation indicates that a detailed examination of the cuticle ornament weighs heavily in analyses of their taxonomic distinctions. A similar sclerite pattern to that of S. papillogyrus has been found in some phosphatized palaeoscolecid cuticle fragments as well as in isolated sclerites. The upper series of nodes and tubercles of these sclerites suggest an accretional mode of sclerite growth. The considerable variation in node number observed across the plates of S. papillogyrus demonstrates that phosphatic palaeoscolecid taxonomy based on relatively minor variations in the number of selerite nodes should perhaps be reconsidered. As the origins of the phosphatized specimens are quite diverse, a large variety of isolated sclerites from the Early Palaeozoic may not reflect actual biodiversity.展开更多
土地混合利用是提高土地利用效率、激发地区发展活力的重要途径,当前少有对农村居民点用地混合利用的系统解析。该研究探索性提出基于多样性和兼容性的农村居民点用地混合利用测度方法,通过实地调研、兴趣点(Point of Interest,POI)数...土地混合利用是提高土地利用效率、激发地区发展活力的重要途径,当前少有对农村居民点用地混合利用的系统解析。该研究探索性提出基于多样性和兼容性的农村居民点用地混合利用测度方法,通过实地调研、兴趣点(Point of Interest,POI)数据抓取、GIS与遥感技术,以珠三角东莞市石排镇塘尾村、谷吓村和福隆村为例,剖析不同类型农村居民点用地混合利用特征及驱动力。结果表明:1)农村居民点用地多样性从小到大为谷吓村、塘尾村、福隆村,其中,土地利用多样性从小到大为谷吓村、福隆村、塘尾村,住宅用地非居住功能多样性从小到大为谷吓村、塘尾村、福隆村,工业用地商业功能多样性从小到大为谷吓村、塘尾村、福隆村;2)农村居民点用地兼容性从小到大为谷吓村、福隆村、塘尾村,其中,土地利用兼容性从小到大为福隆村、谷吓村、塘尾村,业态兼容性从小到大为谷吓村、福隆村、塘尾村;3)综合多样性和兼容性指标的农村居民点用地混合利用度从小到大为谷吓村、福隆村、塘尾村。塘尾村受乡村旅游政策及村域的历史和人文资源驱动,农村居民点用地混合利用程度高;谷吓村交通和区位良好,但仅有沿交通干道两侧的村民发展商业,农村居民点用地混合利用度相对较低;福隆村受珠三角外向型经济带动并充分利用产城融合更新政策发展工业,农村居民点用地混合利用程度较高。农村居民点用地混合利用由多样性和兼容性共同决定,研究可为编制村庄规划、协同推进乡村产业发展与人居环境提升提供决策依据。展开更多
基金financially supported by the Major Basic Research Project of the Ministry of Science and Technology of China under Grants: 2013CB835002the National Natural Science Foundation of China under Grants: 41272036
文摘SEM analysis of trunk ornamentation on a compressed palaeoscolecid fossil from the Shipai fauna, Cambrian Series 2 and Stage 4 at Three Gorges, South China, allows a reassignment of the material to a new taxon, Sanxiascolex papillogyrus gen. et sp. nov. The preserved body is entirely annulated. Each annulus is ornamented by four rows of irregularly alternating plates and each plate bears numerous tubercles at the marginal region and a variable number （zero to six） of nodes at its central part. These features are unique among known palaeoscolecids. Comparative analyses with other compressed palaeoscolecid macrofossils and phosphatized material on the pattern of trunk ornamentation indicates that a detailed examination of the cuticle ornament weighs heavily in analyses of their taxonomic distinctions. A similar sclerite pattern to that of S. papillogyrus has been found in some phosphatized palaeoscolecid cuticle fragments as well as in isolated sclerites. The upper series of nodes and tubercles of these sclerites suggest an accretional mode of sclerite growth. The considerable variation in node number observed across the plates of S. papillogyrus demonstrates that phosphatic palaeoscolecid taxonomy based on relatively minor variations in the number of selerite nodes should perhaps be reconsidered. As the origins of the phosphatized specimens are quite diverse, a large variety of isolated sclerites from the Early Palaeozoic may not reflect actual biodiversity.
文摘土地混合利用是提高土地利用效率、激发地区发展活力的重要途径,当前少有对农村居民点用地混合利用的系统解析。该研究探索性提出基于多样性和兼容性的农村居民点用地混合利用测度方法,通过实地调研、兴趣点(Point of Interest,POI)数据抓取、GIS与遥感技术,以珠三角东莞市石排镇塘尾村、谷吓村和福隆村为例,剖析不同类型农村居民点用地混合利用特征及驱动力。结果表明:1)农村居民点用地多样性从小到大为谷吓村、塘尾村、福隆村,其中,土地利用多样性从小到大为谷吓村、福隆村、塘尾村,住宅用地非居住功能多样性从小到大为谷吓村、塘尾村、福隆村,工业用地商业功能多样性从小到大为谷吓村、塘尾村、福隆村;2)农村居民点用地兼容性从小到大为谷吓村、福隆村、塘尾村,其中,土地利用兼容性从小到大为福隆村、谷吓村、塘尾村,业态兼容性从小到大为谷吓村、福隆村、塘尾村;3)综合多样性和兼容性指标的农村居民点用地混合利用度从小到大为谷吓村、福隆村、塘尾村。塘尾村受乡村旅游政策及村域的历史和人文资源驱动,农村居民点用地混合利用程度高;谷吓村交通和区位良好,但仅有沿交通干道两侧的村民发展商业,农村居民点用地混合利用度相对较低;福隆村受珠三角外向型经济带动并充分利用产城融合更新政策发展工业,农村居民点用地混合利用程度较高。农村居民点用地混合利用由多样性和兼容性共同决定,研究可为编制村庄规划、协同推进乡村产业发展与人居环境提升提供决策依据。
