The diatom genus Hantzschia (Bacillariophyta) in Xinjiang Province, China

Abstract

Hantzschia species are uncommon in Xinjiang Province, usually found in small populations and found only in a few samples. However, the diversity in the region is relatively high, with 13 species and 1 variety being identified. Except for the cosmopolitan species H. amphioxys, H. abundans, H. virgata and H. distinctepunctata, most of the taxa in Hantzschia observed in this region have limited distributions, including H. vivacior, H. nitzschioides, H. compacta, H. barckhausenii, H. longa and H. vivax, as well as the species described herein as new. Four new species of Hantzschia are described: H. pseudobardii, H. sinensis, H. yili and H. subrobusta, a further two interesting species, H. vivacior and H. nitzschioides are documented with light and scanning electron microscopy. All species described are compared with other similar Hantzschia taxa from other localities or compared to holotype specimens. These data show a higher diversity of diatoms in Xinjiang Province than previously understood and provide additional information for understanding their biogeography.

A new species of Achnanthes (Bacillariophyceae) from a freshwater habitat in a karst landform from south‐central China

“…() and modified as described in You et al . (). Cleaned diatoms were mounted in Naphrax® (Robert Charles laboratories Ltd., UK) for light microscopy (LM), LM observations were made with an Olympus BX‐53 microscope fitted with differential interference contrast (DIC) optics and an Olympus DP‐80 digital camera.…”

“…Processing and observations: In the laboratory, Microwave Accelerated Reaction System (Model MARS, CEM Corporation, Mathews, NC, USA) was used to digest samples, following the procedures of Parr et al (2004) and modified as described in You et al (2015). Cleaned diatoms were mounted in Naphrax ® (Robert Charles laboratories Ltd., UK) for light microscopy (LM), LM observations were made with an Olympus BX-53 microscope fitted with differential interference contrast (DIC) optics and an Olympus DP-80 digital camera.…”

Three new freshwater species of the genus Achnanthidium (Bacillariophyta, Achnanthidiaceae) from Taiping Lake, China

“…In the laboratory, diatom samples were cleaned with concentrated nitric acid using the Microwave Accelerated Reaction System (Model MARS, CEM Corporation, Charlotte, USA) (Parr et al 2004), with a pre-programmed digestion scheme (temperature, 180℃) (You et al 2015;Yu et al 2017). Next, samples were alternately centrifuged for 5 min at 3500 rpm (TDZ5-WS, Luyi Corporation, Shanghai, China) and washed six times using distilled water until the pH of the sample was close to neutral.…”

Two new Cymatopleura taxa (Bacillariophyta) from Xinjiang, China with slightly twisted frustules

“…Samples were field-fixed in 4% formaldehyde, water temperature and pH were measured with a HANNA HI 98128 (HANNA instruments, Ann Arbor, MI) pH meter on site. In the laboratory, samples were treated with concentrated nitric acid using the Microwave Accelerated Reaction System (Model MARS, CEM Corporation, Charlotte, USA) (Parr et al 2004) and a pre-programmed digestion scheme (temperature: 180 °C, ramping up to the desired temperature in 15 min, then maintain that temperature for 15 min) (You et al 2015a). After digestion, samples were alternatively centrifuged for 5 minutes at 3500 rpm (TDZ5-WS, Luyi Corporation, Shanghai, China), washed with distilled water and decanted, ca.…”

“…We have begun to review the species occur--ring in Xinjiang Region, and many new species have already been described from this little-explored area in the northwest of China (Kociolek et al 2015;You et al 2008You et al , 2009You et al , 2013You et al , 2015a. The purpose of the present study is to re-examine the Cymatopleura taxa from Xinjiang Region based on observations from light and scanning electron microscopy, and to describe two new species of the genus (C. aquastudia and C. xinjiangiana) that are twisted about the apical axis.…”