Morphology and ultrastructure of Sellaphora constrictum sp. nov. (Bacillariophyta), a new diatom from southern China

Abstract

A new diatom species, Sellaphora constrictum sp. nov., is reported from a karst landform in the Maolan Nature Reserve, Guizhou Province, China. Valves of the new species are broadly linear, slightly constricted in the middle part of the margins and have round apices, an undulate filiform to lateral raphe, a narrow axial area and a narrow conopeum bordering axial area on each side. This species also has undulate ridges along the margin and near the center of the valve, giving the impression of longitudinal ridges on either side of the axial area under light microscopy. Internally, a round opening is present in the apex of the valve, and thickened transverse bars are absent in this region. There are two types of areolae on the valve exterior. Together these features distinguish the new species from all others currently assigned to the genus. We discuss the growing number of new species and genera from freshwater environments in China, and interpretations about the delineation of the genus Sellaphora.

Three new subaerial Achnanthidium (Bacillariophyta) species from a karst landform in the Guizhou Province, China

“…Daqikong is famous for its steep hills and natural canyon, the Mengtang (Dagou) River flows through canyon, there are many tourists throughout the year. Maolan Nature Reserve is protected by the Chinese government and international agreements through inclusion as part of International Man and Biosphere Reserve Network (UNESCO) (You et al 2017), and consequently it is less affected by human factors. These two areas are adjacent, and the distance between sampling sites is ca.…”

“…While working on the diatom biodiversity of a karst landform in Guizhou, we observed many interesting diatom species, resulting in the description of one new genus and eleven new taxa (Kociolek et al 2016a(Kociolek et al , b, 2019Lowe et al 2017;You et al 2016You et al , 2017You et al , 2019Yu et al 2017b). The aim of this article is to describe three new Achnanthidium species, based on light microscopy (LM) and scanning electron microscopy (SEM) of cleaned materials from this same karst landform.…”

Eunotia (Bacillariophyta) biodiversity from high altitude, freshwater habitats in the Mugecuo Scenic Area, Sichuan Province, China

“…Processing and observations: Samples were treated in the laboratory with concentrated nitric acid using the Microwave Accelerated Reaction System (Model MARS, CEM Corporation, Charlotte, NC, USA) and a preprogrammed digestion scheme (temperature: 180°C, ramp: 15 min, hold: 15 min). Cleaned diatoms were mounted in Naphrax ® as following the procedure described in You et al (2017) for light microscopy (LM) analysis or otherwise spread on aluminum foil and mounted onto stubs for scanning electron microscopy (SEM). LM observations were made with an Olympus BX53 microscope fit for DIC optics (100 × objective, numerical aperture 1.4), and SEM examination was conducted using a Hitachi SU 8010 scanning electron microscope (2 kV) (Hitachi, Tokyo, Japan).…”

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

“…As a part of our continuing study of the freshwater diatoms of Guizhou Province, China (Kociolek et al 2016a(Kociolek et al , 2016bYou et al 2016You et al , 2017Lowe et al 2017;Yu et al 2017), we encountered a species of Achnanthes for which we can find no previous description. The purpose of the present report is to present light and scanning electron microscope observations of this Achnanthes species from Guizhou, and to offer a formal description of it as a species new to science.…”