Freshwater Cocconeis species (Bacillariophyceae) from Southeastern Brazil, and description of C. amerieuglypta sp. nov.

Integrative taxonomic description of two new species of the Cocconeis placentula group (Bacillariophyceae) from Korea based on unialgal strains

“…This is in contrast to the new species C. sijunghoensis which we found only in one year in one water body in North Korea and for which we could find no real match in the presented data and morphologically similar taxa is difficult because, on the one hand, our study provides no data on the morphological variability of the newly described species in the environment before undergoing cultivation. On the other hand, no material derived from clonal culturing is available in current studies on freshwater Cocconeis taxa (e.g., Stancheva 2019, Wetzel et al 2019, Costa et al 2020. For this reason, molecular data are missing and morphological changes during the life cycle have not been documented.…”

“…The presumed single species populations in environmental samples do not give us the certainty that we are using morphologically stable features for the differentiation of species. For example, in the paper by Costa et al (2020) the high quality SEM figs 25-28 of C. amerieuglypta L. F. Costa, C. E. Wetzel & Ector are, in our understanding, more than one species (but which valve represents C. amerieuglypta?)…”

Cocconeis crisscrossis sp. nov., a new monoraphid diatom (Bacillariophyta) from southern China

“…The areolae of the RV are fine and often have a semicircular hyaline area near the valve ends, while the areolae of the SV are relatively coarse extending to the valve edge and lacking a hyaline area. Striae are usually uniseriate in freshwater species and the poroids are closed by hymenes ( Costa et al 2020 ). The frustule structure of Cocconeis is diverse and complex, species delineation requires detailed observations of the RV morphology, the SV and their connecting elements including valvocopulae and the cingulum ( Potapova and Spaulding 2013 ; Stancheva 2022 ).…”