Examination of types in the Fragilaria vaucheriae–intermedia species complex

In a previous paper, we presented the results of type examination of the Fragilaria pectinalis–capitellata species complex, species which have a unilateral central area and fine striae. Here, we present the results of type examination of the Fragilaria vaucheriae–intermedia species complex, species which have a unilateral central area and coarse striae (＜13 striae per 10 µm). Synedra vaucheriae var. doformis Grunow and S. vaucheriae var. distans Grunow are synonyms of F. vauchriae (Kütz.) J.B.Petersen. F. intermedia Grunow is also a synonym of F. vauchriae. However, some of the figures for F. intermedia that were published by Van Heurck are a new taxon sometimes identified as F. intermedia. This new taxon is described here as Fragilaria neointermedia.This is an open access paper (Directory of Open Access Scholarly Resources). The attached file is the pubiished pdf. https://www.kahaku.go.jp/research/publication/botany/download/39_1/BNMNS_B39-1_1-9.pd

Centric diatoms of large rivers and tributaries in Hungary: morphology and biogeographic distribution

Centric diatoms of 107 different Hungarian running waters were investigated. Among them the largest was the River Danube, from which more than one hundred plankton samples were analysed by scanning electron microscopy (SEM). Only one sample was analysed from creeks, which were the smallest running waters analysed in this study. There were also channels with slow currents flowing out of rivers or connecting different rivers.In total, 41 centric taxa belonging to 11 genera were found during this study. The average number of taxa found in a single watercourse was 7, the maximum 40 and the minimum 1. Cyclotella meneghiniana was the most frequently encountered species (present in 60% ofsites). Twelve taxa were found in more than 20% of sites, 7 taxa between 5–10% and 6 taxa only in one site

Connecting the morphological and molecular species concepts to facilitate species identification within the genus Fragilaria (Bacillariophyta)

This paper explores the diversity and taxonomy of species within Fragilaria sensu stricto, an abundant and ecologically important diatom genus, taking advantage of cultured and DNA-barcoded material. The goal is to facilitate the identification of European taxa within this complex, providing a unified view on morphological and molecular diversity. There is a general agreement that the separation of species within the group of Fragilaria is difficult because morphological descriptions of species are not consistent between authorities, ongoing taxonomic revisions have resulted in species described with standards of the late 20th and 21st centuries alongside descriptions based on 19th century (light microscopical) criteria, and because not all diagnostic characters can be seen in all specimens encountered in routine analyses. Consequent confusion could blur potentially important ecological distinctions between species. Our study demonstrated that some species defined on morphological criteria could be confirmed using the rbcL chloroplast gene as a genetic marker, for example, Fragilaria gracilis, Fragilaria tenera, Fragilaria perminuta, and Fragilaria subconstricta. However, even for those species, preliminary identifications based on morphology often differed from identifications based on phylogenetic clustering combined with detailed morphological study. Clades were well-defined by rbcL, but based on morphology, the terminal taxa of these clades did not match the currently described Fragilaria species. To clarify recognition of these taxa, we describe three new species: Fragilaria agnesiae, Fragilaria heatherae, and Fragilaria joachimii