Fottea - Ahead of Print
Cryptic diversity in the marine diatom genus Climaconeis (Berkeleyaceae, Bacillariophyta) with description of Climaconeis aucklandensis sp. nov.
Rinat M. Gogorev, Olga Davidovich, Nickolai Davidovich, Yekaterina Bedoshvili, Vyacheslav Yu. Nikulin, Arthur Yu. Nikulin
Fottea X:X | DOI: 10.5507/fot.2026.001 
Clonal cultures of the diatom genus Climaconeis from the Black Sea (Crimea), Mediterranean Sea (Anatolia), Atlantic Ocean (Canary Islands), and Southwest Pacific Ocean (Auckland, New Zealand) were investigated. The Auckland population is described as Climaconeis aucklandensis sp. nov., distinguished by 4-12 H-shaped plastids per cell, a larger valve size range, and different stria density. We used morphological (LM, SEM, TEM, LSM), molecular (rbcL), and ecophysiological (salinity tolerance) analyses to characterize C. aucklandensis, C. scalaris, and Climaconeis cf. scalaris. Black Sea and Atlantic specimens...
Halamphora izadii sp. nov., a new diatom species from the hottest place on earth, Lut Desert, Iran
Somayyeh Kheiri, Mark B. Edlund, Sarah A. Spaulding, Cüneyt Nadir Solak, Jafar Sabouri, Łukasz Peszek
Fottea X:X | DOI: 10.5507/fot.2026.002
In a study on the diatom flora of the Lut desert, the hottest point on Earth, we report a new species Halamphora izadii sp. nov. This species is described based on LM and SEM observations and belongs among the many small-sized species distributed across the Halamphora lineage. The new species can withstand extreme air temperatures and high salinity concentrations found in waterways of the Lut Desert. Halamphora izadii is differentiated by possessing fine striae, hardly resolvable in LM at 26-30 striae in 10 µm, a subcentral raphe, and areolae opening externally by narrow slit-like openings with dilated ends. The species...
A new Platessa Lange-Bertalot species and a Planoplatessa Kulikovskiy et al. (Achnanthidiaceae, Bacillariophyta) species from two high altitude lakes in southwest China
Kun Zheng, Ji-Min Huang, Jun Luo, Cheng-Zhi Ding, John Patrick Kociolek, Yan-Ling Li
Fottea X:X | DOI: 10.5507/fot.2026.003
A new monoraphid diatom species, Platessa deqinensis sp. nov., and Planoplatessa joursacensis (Héribaud) Kulikovskiy et al. are reported from high-altitude lakes of the Hengduan Mountains region in southwestern China. Detailed morphological characteristics of both species are documented based on light microscopy (LM) and scanning electron microscopy (SEM). Platessa deqinensis is similar to P. mugecuonesis, P. lanceolata, P. stewartii and P. bahlsii, but it differs from these species in terms of its valve outline, size, stria density and SEM details. Planoplatessa joursacensis, is illustrated with...
Taxonomic revision of Eunotia indica and infraspecific taxa (Bacillariophyceae) reported by Frenguelli from the Esteros del Iberá (Argentina)
Amelia A. Vouilloud, José M. Guerrero, Silvia E. Sala
Fottea X:X | DOI: 10.5507/fot.2026.004
Eunotia indica, originally described from Banka Island (Indonesia), has been reported worldwide although there is confusion about the identity and actual distribution of this supposedly cosmopolitan species. In 1933 Frenguelli reported 55 different taxa of Eunotia from the Esteros del Iberá (Argentina), a vast wetland with a high rate of endemism. One of the species reported was E. indica together with two new varieties. We examined the original materials contained in the Frenguelli Collection to study the valve morphology of these taxa and elucidate their taxonomic position. For comparison, we also analyzed the original material of E....
Three novel species of Microglena (Chlamydomonadales, Chlorophyceae) from China revealed by an integrative approach
Yangliang Chen, Qingyu Dai, Benwen Liu, Huan Zhu, Guoxiang Liu
Fottea X:X | DOI: 10.5507/fot.2026.005
The taxonomic status of Microglena as a genus within Chlamydomonadales was reconfirmed. Many strains previously assigned to Chlamydomonas have been reclassified as members of Microglena, and new species continue to be described under this genus. In this study, we investigated three strains isolated from China using an integrative approach. Phylogenetic analyses based on 18S and ITS rDNA sequences, combined with comparisons of compensatory base changes (CBCs) for the conserved regions of ITS-2 secondary structure revealed that the three strains represent three independent species included in Microglena, and they are distinct...
Navicula teodorae, a new raphid diatom species (Naviculaceae, Bacillariophyceae) from thermomineral springs in Serbia
Ana Milićević, Slađana Popović, Božica Vasiljević, Jelena Krizmanić, Bart Van de Vijver, Olga Jakovljević
Fottea X:X | DOI: 10.5507/fot.2026.007
During a survey of the diatom flora of thermomineral springs in Serbia, an unknown Navicula taxon was observed that could not be identified using the currently available literature. Based on detailed light and scanning electron microscopy observations, the unknown species, characterised by its narrowly lanceolate valve outline, distinctly different valve dimensions, and strongly hooked terminal raphe fissures, is described as Navicula teodorae. Morphologically, N. teodorae can be differentiated from similar species such as Navicula cryptotenella, N. breitenbuchii and N. veneta by a combination of valve shape,...