Fottea, 2025 (vol. 25), issue 1
Original article
Diatom studies three decades into the molecular age: a bibliometric analysis reveals genetic underexploration of diatoms compared to other taxa
Jan Kollár, Kateĝina Kopalová, Tyler J. Kohler
Fottea 2025, 25(1):1-11 | DOI: 10.5507/fot.2024.009 
Diatoms are among the most diverse and environmentally significant protists on Earth. Like many other organismal groups, a large portion of their diversity appears to lie beyond the resolution of the traditional light microscopy-based methods routinely and sometimes exclusively utilized in their investigation. Although the technological and conceptual developments in the fields of molecular biology and bioinformatics unlocked a remarkable opportunity to study diatoms in a previously unimagined depth and breadth, molecular diatomists anecdotally claim that diatoms remain genetically understudied compared to other taxa. However, this claim has never...
Miocene Aulacoseira species from the Virgin Valley Formation, Nevada, U.S.A.
Peter A. Siver
Fottea 2025, 25(1):12-52 | DOI: 10.5507/fot.2024.005
Aulacoseira Thwaites is one of the oldest known diatom genera to inhabit freshwater ecosystems, having been recorded from multiple localities from the late Cretaceous. The genus continued to evolve throughout the Cenozoic and today continues to thrive in aquatic environments globally, often forming an important contributor to phytoplankton communities. Morphological characters that define Aulacoseira had largely evolved by the Eocene, and many additional species have been uncovered since that time, especially in the Miocene. The Virgin Valley Formation, located in the northwestern portion of Nevada, USA, represents an extensive deposit...
A new freshwater diatom genus Trialacinia gen. nov. (Naviculaceae: Bacillariophyta) from Guangxi Autonomous Region, China
Yan Liu, John Patrick Kociolek, Xiaoyi Chen, Xinxin Lu, Yawen Fan
Fottea 2025, 25(1):53-60 | DOI: 10.5507/fot.2024.007
A new genus and species of freshwater diatoms from the Guangxi Autonomous region of southern China were studied with light and scanning electron microscopy. The newly proposed genus has several features that assign it to the Naviculaceae, including symmetry about the apical, transapical and pervalvar axis, slit-like areolae that are occluded internally by fine hymenes, hook-like external distal raphe ends and the presence of an internal auxillary rib bordering the raphe sternum. These features also suggest a strong morphological similarity with the genus Navicula. The new genus and species, however, have several external flaps of silica on the...
Prestauroneis furatensis sp. nov., a new diatom species from the River Euphrates, Iraq
Heba Mohamad, Regine Jahn, Adil Al-Handal, Maitham Al-Shaheen, Wolf-Henning Kusber, Jonas Zimmermann, Nélida Abarca
Fottea 2025, 25(1):61-67 | DOI: 10.5507/fot.2024.008
In a comparative study on epiphytic diatoms in the Rivers Euphrates and Tigris (Iraq), one of the major drainage basins in the Middle East, we report a new species, Prestauroneis furatensis sp. nov., It was present in low abundances (up to 5%) solely in the summer samples of the River Euphrates on the macrophytes Ceratophyllum demersum, Typha domingensis, Potamogeton perfoliatus, and Najas minor. Light and scanning electron microscopic observations revealed distinct morphological traits that differentiated P. furatensis from other species, leading to its identification as a new species. Detailed physical-chemical...
Trebouxia barrenoae sp. nov. (Trebouxiophyceae, Chlorophyta), a new lichenized microalga widespread in temperate ecosystems
Tamara Pazos, Patricia Moya, Isaac Garrido-Benavent, César D. Bordenave, Ayelén Gazquez, Salvador Chiva
Fottea 2025, 25(1):68-80 | DOI: 10.5507/fot.2024.010
The genus Trebouxia includes the most widespread green microalgae inhabiting lichen thalli worldwide. Nonetheless, the vast majority of species-level phylogenetic lineages within this genus lack a formal taxonomic description and, to date, only 31 species have been accepted. In this study, we utilized an integrative taxonomic approach to describe the new species Trebouxia barrenoae Pazos, Chiva, Garrido-Benavent et Moya, a frequent symbiont in different lichens which is phylogenetically circumscribed to Trebouxia clade S. The ultrastructural features of the new microalga were studied through light, confocal, and electron microscopies;...
New and interesting species of the genus Gomphosinica Kociolek, You et Wang (Bacillariophyta) from Xizang Autonomous Region, China
Hanxun Jv, Yutong Jiang, Xinyuan Na, John P. Kociolek, Huan Zhu, Guoxiang Liu, Maxim Kulikovskiy, Yanling Li, Yawen Fan, Yan Liu
Fottea 2025, 25(1):81-90 | DOI: 10.5507/fot.2024.012
During the investigation of freshwater biodiversity of Xizang Autonomous Region, diatom samples were collected from several habitats and two new species were discovered and are formally described herein, namely, Gomphosinica stoermeri Liu, Kociolek et Li sp. nov., and Gomphosinica qii Liu, Kociolek et Li sp. nov. Both of these new species have biseriate striae, straight raphe ends, pseudosepta at both ends and a hooded stigma covering in the central area. Gomphosinica stoermeri can be separated from other similar species by its clavate outline, bluntly rounded headpole, rounded footpole, small and rounded central area formed by...
Desmonostoc cockrellii sp. nov. (Nostocales, Cyanobacteria): a new record of a subaerophytic species from The Habitat Penang Hill, Malaysia
Billy Lim Chun Ginn, Choi Yi Lau, Nur Afiqah Asma, Noor Aziah Serri, Paul Broady, Peter Convey, Narongrit Muangmai, Faradina Merican
Fottea 2025, 25(1):91-104 | DOI: 10.5507/fot.2024.013
Subaerophytic cyanobacterial diversity is poorly known in Malaysian rainforests generally and at Penang Hill specifically. A new subaerophytic species of cyanobacteria, Desmonostoc cockrellii sp. nov., was isolated from rocky surfaces along trails in The Habitat Penang Hill, Malaysia. Polyphasic analysis identified unique morphological structures such as larger dimensions of akinetes and bubble formations within colonies grown on agarized medium. Toxin-encoding genes for microcystin, nodularin, cylindrospermopsin, anatoxin-a and saxitoxin were not detected. The 16S rRNA gene phylogeny inferred by both maximum likelihood and Bayesian inference...
Ultrastructure of Tryblionella qinghainensis sp. nov., T. apiculata and T. levidensis (Bacillariophyta) from Lake Qinghai (China), with reference to the marginal ridge
Yi-Dan Ma, Bing Liu, Patrick Rioual, Ji-Yan Long, Ya-Lun Ma
Fottea 2025, 25(1):105-120 | DOI: 10.5507/fot.2024.011
Three Tryblionella species found at the same locality in Lake Qinghai, the largest inland saline water lake of China, are studied by using light and scanning electron microscope. One species is proposed as new to science and named Tryblionella qinghainensis sp. nov. The other two species are identified as T. apiculata W. Gregory and T. levidensis W. Smith. Tryblionella qinghainensis sp. nov. is characterized by its linear-lanceolate valve outline, broad axial sternum, a stria density to fibula density ratio of ca. 1.9:1, alveolate striae, and a simple standing lamella-like marginal ridge unperforated. Several...