Sand samples collected from three freshwater and brackish sandy beaches in Southern Brazil have revealed the presence of a new hyaline araphid diatom belonging to a new genus. The new genus, Rimoneis M.Garcia, is characterized by the presence of two slits at each apex, a wide sternum, small areolae occluded by hymenes, striae with internal openings in a cavity, valve edge with simple spines or a ridge, the absence of rimoportulae, and plain open bands. Two species belong to the new genus : the type species Rimoneis M.Garcia sp. nov. from Southern Brazil and Rimoneis densestriata (Hust.) M.Garcia comb. nov. from Java (Asia). Rimoneis is ecologically and morphologically different from the marine hyaline diatoms Pravifusus, Hyaloneis (both without areolae), Synedropsis and from freshwater fragilarioid genera such as Pseudostaurosira, Pseudostaurosiropsis and Synedrella (distinct in colony formation, areolae occluded by volae and simple striae with internal openings).
A new fossil diatom species Cyclotella kitabayashii H.Tanaka sp. nov. is described from Pliocene sediment of the Tsubusagawa Formation in Kyushu, southwestern Japan. The new species is characterized by larger circular valves and smaller elliptical valves, valve faces that are tangentially undulate with fultoportulae arranged in a circular pattern in the central area with many areolae. Internally, there are alveolae in the marginal area. Every costa or every second (rarely third) costa is recessed and bears a fultoportula. Valve face and mantle fultoportulae have uniquely shaped satellite pore covers. The authors were unable to find any taxon that has the combination of these characteristics and accordingly propose C. kitabayashii as a new species. The new species is compared to similar taxa.
Lake Kinrin, a small and shallow lake in Yufuin Town, Oita Prefecture receives two kinds of groundwater inflow. One is high-temperature water of 32-35℃ from a hot spring and the other is relatively low-temperature water of 15-20℃ from springs in the bottom and around the periphery of the lake. The diatom flora in the lake influenced by high-temperature water was compared with that of two sites lacking such influence. In total, 147 diatom taxa belonging to 46 genera were recorded. At the site influenced by the hot spring, Achnanthes exigua and Nitzschia amphibia were dominant, and Pinnularia joculata was a characteristic species in the community. At the other sites, Nitzschia fonticola, Fragwasilaria neoproducta, Planothidium lanceolatum, Martyana martyi, and Staurosira elliptica were the dominant species.
The fine structure of Aulacoseira crassipunctata Krammer in Japan was examined us- ing light (LM) and scanning electron (SEM) microscopy. The most defining characteristic of this Aulacoseira species is its lack of rimoportulae. This paper reports the unique valve structure of A. crassipunctata from three localities : Bishamon Pond (Fukushima Pref.), Lake Kussharo (Hokkaido) and Sawano-ike Pond (Kyoto Pref.).
Five sets of science textbooks for elementary schools and lower secondary schools in Japan were surveyed to determine their coverage of algae with reference to diatoms. The textbooks were first published in the early 1950s and thereafter revised almost every 10 years, in conformity with the national science curriculum revision. In textbooks for elementary schools, the number of algal species was largest in the 1962 version and thereafter decreased considerably. The most frequent genus among diatoms was Pinnularia. However, no algal name appeared in the last (2002) version, though the term diatom still appeared in the textbooks. In textbooks for lower secondary schools, the number of algal species was largest in the 1972 version and thereafter decreased, but not so much as in the elementary school textbooks. For the last ten years algae have been taught only from morphological and ecological viewpoints and even there only briefly. Pinnularia was also the most frequent genus among diatoms in lower secondary school science textbooks. According to the newly revised science curriculum, which is being enacted in 2011 for elementary schools and in 2012 for lower secondary schools, diatoms will possibly be taught as organisms living in fresh water, as fish food and as producers in aquatic ecosystems in elementary schools more frequently, but in lower secondary schools they will continue to be taught in line with the status quo.
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