Fottea X:X | DOI: 10.5507/fot.2026.007

Navicula teodorae, a new raphid diatom species (Naviculaceae, Bacillariophyceae) from thermomineral springs in Serbia

Ana Milićević1, Slađana Popović1, Božica Vasiljević2, Jelena Krizmanić1, Bart Van de Vijver3, 4, Olga Jakovljević1
1 University of Belgrade, Faculty of Biology, Department of Algology and Mycology, Institute of Botany and Botanical Garden "Jevremovac", Takovska 43, 11000 Belgrade, Serbia
2 University of Belgrade, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, Department of Hydroecology and Water Protection, Bulevar despota Stefana 142, 11108 Belgrade, Serbia
3 Meise Botanic Garden, Research Department, Nieuwelaan 38, 1860 Meise, Belgium
4 University of Antwerp, Department of Biology - ECOSPHERE, Universiteitsplein 1, 2610 Wilrijk, Belgium

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, size, and stria characteristics. The new species seems to prefer moderately warm, alkaline, mineral-rich waters, and was (sub-)dominant in epilithic and epipelic samples from several thermomineral springs. The discovery of this taxon highlights the biodiversity potential of thermomineral springs in the Balkan region.

Keywords: biodiversity, morphology, Navicula, new species, Serbia, thermomineral springs

Received: January 23, 2026; Revised: March 31, 2026; Accepted: May 18, 2026; Prepublished online: September 9, 2026 

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