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The freshwater red algal genus Sheathia is one of the most species‐rich genera in the Batrachospermales, containing species with heterocortication (both bulbous and cylindrical cells covering the main axis) and homocortication (only cylindrical cells). The hidden diversity of homocorticated Sheathia species has gained research momentum. Recent studies have revised these taxa and described many new species. In this study, a new homocorticated Sheathia species is described and illustrated from Yunnan, China, based on phylogenetic analyses of DNA sequence data. Sheathia yunnanensis sp. nov is morphologically characterized by having homocortication, carpogonium with bent or slightly constricted lanceolate trichogyne, large carposporophyte and carposporangium. However, it is only distinguishable from other homocorticated species by DNA sequence data. Phylogenetic analyses based on rbcL, COI‐5P, psbA and concatenated rbcL + COI‐5P alignment indicated that Sheathia yunnanensis form an independent clade from other homocorticated Sheathia species with high interspecific divergence (rbcL: 3.9–4.9%/37–54 bp, COI‐5P: 6.1–6.6%/36–39 bp and psbA: 2.2–3.9%/18–32 bp). Sheathia yunnanensis, as the first gametophyte of Sheathia species reported in Yunnan, differs from other Sheathia species reported only as 'Chantransia' sporophyte stage. As a result of this study, the number of Sheathia species recognized in China increased to eight, including one heterocorticate and seven homocorticated including three only known from the 'Chantransia' sporophyte stage. The description of this new species expands the diversity of Sheathia in the world. [ABSTRACT FROM AUTHOR]

Summary: The freshwater red alga Nemalionopsis shawii Skuja is first reported for mainland China from specimens collected in Guangdong and Yunnan Province. Morphological observations and molecular sequences of rbcL and cox1 genes were used to identify and analyze the phylogenetic position of the samples. Samples from China formed a monophyletic clade with other N. shawii samples from Japan, Indonesia, and Nepal with robust support values. The pairwise genetic distances for N. shawii between the samples from China and other samples were 0.2–1.5% and 1.0–2.4% for rbcL and cox1, respectively. Both male and female reproductive structures were observed in the specimens from Guangdong, but only monosporangia in the specimen from Yunnan. The samples from China increase the diversity of morphological measurements for N. shawii. The discovery of this genus in mainland China results in a new record of a freshwater red alga for this country. [ABSTRACT FROM AUTHOR]

There is a concern about the increasing prevalence of health problems related to the ingestion of fluoride (F - ) in the developing world. Drinking water is one important source of F - , and the concentration of F - needs to be known to ensure the safety of drinking water. In this study, F - levels in drinking water were investigated across Taiyuan in Shanxi Province, China. Spatial-temporal distribution characteristics and potential associated health risks were analyzed using GIS. We collected 485 samples from shallow wells without any defluoridation treatments between 2008 and 2016. After analyzing the samples of F - content we found that mean F - levels of urban areas (0.61 ± 0.39 mg L -1 ), suburban areas (0.70 ± 0.87 mg L -1 ) and for all of Taiyuan city (0.63 ± 0.56 mg L -1 ) were in optimum range based on the recommendation by USEPA. However, individual locations within industrial areas (e.g. Gujiao District) had higher F - levels (1.06 mg L -1 ). A concerning result showed that 12.37% of tested locations had F - concentrations larger than 1.0 mg L -1 . We calculated F - Health Risk Indices (HRIs F ) and found that highest were associated with suburban areas, especially in the year 2009 and 2010. However, from 2008 to 2016, overall F - levels and HRIs F of the sampled groundwater in Taiyuan City showed a decreasing trend. HRIs F in suburban areas was higher than urban areas, possible due to the heavily prevalent coal mining industry in those areas. Specific policies should be formulated to address HRIs F ., (Copyright © 2018 Elsevier Inc. All rights reserved.)