Fottea - Ahead of Print
Revisiting Chrysococcus (Chrysophyceae): new phylogenetic evidence and evolutionary implications
Veronica Malavasi, Martin Pusztai, Katarzyna Jankowska, Bożena Zakry¶, Pavel ©kaloud
Fottea X:X | DOI: 10.5507/fot.2025.001 
Loricate golden algae (Chrysophyceae) are photosynthetic microorganisms characterized by a lorica, a rigid or semi-rigid protective casing made of organic material, sometimes reinforced with silica or iron. The lorica's diverse shapes and intricate ornamentation serve as both adaptive strategies and taxonomic markers. Here, we identified, for the first time, the molecular phylogenetic position of a loricate genus Chrysococcus, based on genetic investigations of two freshwater populations in Poland. The genus was resolved to form a well-supported clade with Chrysosaccus within the order Chrysosaccales. Accordingly, this order represents...
Frustulia lineata and Frustulia magnifica, two new species of diatom from south Brazil
Paula Carolina Ferreira, Vanessa Merlo Kava, Rodrigo Aluisio, Thelma Alvim Veiga Ludwig
Fottea X:X | DOI: 10.5507/fot.2025.002
During studies on the diversity of Frustulia in the state of Paraná, Brazil, two different morphological populations did not correspond exactly to any known described species. This paper describes these species as Frustulia lineata sp. nov. and Frustulia magnifica sp. nov. The samples were collected in lotic environments inserted in the south Brazil Atlantic Forest region. Frustulia lineata sp. nov. is mainly characterized by linear-lanceolate valves with small dimensions, sharing morphological similarities with Frustulia marginata Amossé and Frustulia saxonica f. indica Sarode et Kamat. Frustulia...
Flavoaurantia, a new genus of the Chlorobotryaceae (Eustigmatales, Eustigmatophyceae) with the single species, Flavoaurantia irregularis
Christie L. Alexandre, Yvonne Němcová, Marvin W. Fawley, Karen P. Fawley
Fottea X:X | DOI: 10.5507/fot.2025.003
An algal strain with the morphological characteristics of the Eustigmatophyceae was isolated from a small pond in Itasca State Park, Minnesota, USA. Phylogenetic analyses of the DNA sequences from the nuclear 18S rDNA and the plastid rbcL loci both placed the strain in the order Eustigmatales and family Chlorobotryaceae. The new strain was not clearly allied with any lineage within the Chlorobotryaceae. Morphological features as determined by both light microscopy and transmission electron microscopy were typical for the Eustigmatales, except for the presence of an irregular surface of the cell wall (including the presence of stipitate or digitate...
Streptosarcina costaricana var. goloustica var. nov. (Klebsormidiophyceae, Charophyta) from soils of Baikal mountains, Russia
Irina N. Egorova, Nina V. Kulakova, Olga N. Boldina
Fottea X:X | DOI: 10.5507/fot.2025.004
The charophyte algae of the genus Streptosarcina (Hormidiellales) are quite rare terrestrial protists, according to current knowledge. The genus consists of two species, S. arenaria and S. costaricana, which are isolated in Eastern Europe and Central America, respectively. Only five strains of the genus have been studied using microscopy and/or molecular methods, based on published data. Here, we examined two strains, IRK-A 417 and 448, isolated from the chestnut soils of the Primorsky Range at the southwestern shore of Lake Baikal. The combination of molecular (18S rDNA, ITS, rbcL) and microscopy data (LM and TEM) was used to...
Sellaphora temporalis sp. nov., Sellaphora catalonica sp. nov., and Nitzschia curvirecta sp. nov.: Three new diatoms (Bacillariophyta) from disconnected pools in the Iberian Peninsula
Guillermo Quevedo-Ortiz, Joan Gomà, Saul Blanco
Fottea X:X | DOI: 10.5507/fot.2025.005
Disconnected pools are temporary habitats of great ecological importance that can maintain high aquatic biodiversity. However, little is known about the composition and distribution of algal communities in the Mediterranean basin. During a diatom flora study conducted on the Iberian Peninsula, several populations of unknown taxa were found. Detailed observations with optical and scanning electron microscopes allowed for the description of three new taxa to science: Sellaphora temporalis sp. nov., Sellaphora catalonica sp. nov., and Nitzschia curvirecta sp. nov. Differential diagnostic criteria with respect to similar taxa are briefly...
Neoluticola (Bacillariophyceae) a new genus of colonial diatoms from tropical America
Julian Simonato, Silvia E. Sala, John P. Kociolek
Fottea X:X | DOI: 10.5507/fot.2025.006
In the framework of a study of the genus Luticola Mann we collected and processed samples from different ecoregions of Argentina, analyzed them with light microscopy (LM) and scanning electron microscopy (SEM). In aerophilous samples collected in Misiones Province, Argentina, we found colonial specimens. The aim of this work is to elucidate the identity of the colonial forms found in aerophilous samples in NE Argentina. In the present study, we describe the genus Neoluticola Simonato, Sala et Kociolek and four species: Neoluticola spinosa Simonato, Sala et Kociolek sp. nov., Neoluticola arrechensis Simonato, Sala et Kociolek...
Widespread and homologous life-history traits within the Rhopalodiales (Bacillariophyceae)
Heidi Abresch, Mark B. Edlund, Scott R. Miller
Fottea X:X | DOI: 10.5507/fot.2025.007
Significant changes have been proposed for the order Rhopalodiales, including subsuming Rhopalodia O.Müll. into Epithemia Kütz. to maintain monophyly and recognition of the genus Tetralunata Hamsher et al. However, hesitancies about adopting these higher-level classifications remain. We report widespread and homologous internal valve and life history traits as evidence to guide higher-level classification within the Rhopalodiales. We provide the first reports of internal valve formations in five species and show examples from six species representing multiple branches in the Rhopalodiales: Epithemia (Rhopalodia) gibba (Ehrenb.)...
Mallomonas intermedia: A case study of speciation and evolutionary dynamics of protists
Pavel ©kaloud, Magda ©kaloudová, Petr Knotek, Iva Jadrná, Martin Pusztai
Fottea X:X | DOI: 10.5507/fot.2025.008
A total of 81 strains morphologically corresponding to the circumscription of Mallomonas intermedia were isolated from 27 freshwater localities across Europe and North America. Molecular genetic analyses revealed two distinct lineages with a strict geographical pattern, which diverged approximately 8 million years ago. According to comparative morphological analyses, we concluded that European populations corresponded to M. intermedia, whereas North American populations were described as a new species, M. retimedia sp. nov. The most notable morphological difference between the species is in the number of pores enclosed in the mesh...
The names of phyla and classes of blue-green algae (cyanobacteria, cyanophytes) and a typified name: Cyanobacteriophyta Oren, Mareą & Rippka
Boris Aleksovski, Svetislav Krstic, Michael D. Guiry
Fottea X:X
Organisms long known as “blue-green algae” or “cyanophytes”, and more recently as “cyanobacteria”, are currently governed by both the rules of the International Code of Nomenclature for algae, plants, and fungi (ICN) and the International Code of Nomenclature of Prokaryotes (ICNP) and a reciprocal principle of code coordination is agreed so that names validated in either codes are treated as valid in the other code. Under the ICN, both descriptive and typified names above the level of family are permitted, and the principle of priority does not apply. The current names in use, along with the typified or descriptive...
Revision of the genus Stauroforma (Staurosiraceae, Bacillariophyceae) based on varieties of Fragilaria virescens described by Albert Grunow
Bart Van de Vijver, Tanja M. Schuster, David M. Williams, Wolf-Henning Kusber
Fottea X:X | DOI: 10.5507/fot.2025.011
A revision of the genus Stauroforma is proposed based on the analysis of several historic slides prepared by Grunow to describe Fragilaria virescens var. exigua. The original materials are analysed using both light and scanning electron microscopy together with a critical examination of the original drawings and notes Grunow made on his new taxa. Based on this, the genus description of Stauroforma is emended and the morphological descriptions of S. exiguiformis and S. inermis are updated. Grunow's variety subsalina is raised to species level as Stauroforma subsalina. A new species, Stauroforma...