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Type: Article
Published: 2022-07-26
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Fragilaria odeloucaensis sp. nov. (Bacillariophyta, Fragilariaceae) a diatom from temporary streams in southern Portugal

Water Laboratory, University of Évora, P.I.T.E. Rua da Barba Rala No. 1, 7005–345 Évora, Portugal; Institute of Earth Sciences - ICT, University of Évora, Rua Romão Ramalho n° 59, 7000–671 Évora, Portugal
Water Laboratory, University of Évora, P.I.T.E. Rua da Barba Rala No. 1, 7005–345 Évora, Portugal; Institute of Earth Sciences - ICT, University of Évora, Rua Romão Ramalho n° 59, 7000–671 Évora, Portugal
Environmental Research and Innovation Department (ERIN), Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, 4422 Belvaux, Luxembourg
Environmental Research and Innovation Department (ERIN), Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, 4422 Belvaux, Luxembourg
Water Laboratory, University of Évora, P.I.T.E. Rua da Barba Rala No. 1, 7005–345 Évora, Portugal; Institute of Earth Sciences - ICT, University of Évora, Rua Romão Ramalho n° 59, 7000–671 Évora, Portugal
Araphid diatoms drylands Iberian Peninsula intermittent streams taxonomy Algae


A new species of araphid diatom is described from a temporary stream in southern Portugal, Fragilaria odeloucaensis sp. nov., which belongs to the group of Fragilaria with widely linear to lanceolate valve outline, spaced striae, lacking spines, and with well-developed apical pore fields. The new taxon can be distinguished based on five unique features within this group, the lanceolate valves with capitate apices, the zig-zagged axial area, the central area with squared fascia, the apical pore fields clearly sunken into the valve apices and the heterovalvar frustules (with respect to striae distancing). Ecological features of the type locality and an additional sampling point where the new species was found are given, together with a discussion of the taxonomic position of the new species within Fragilaria, and the approach used herein for the identification of diagnostic features. This approach includes a detailed analysis of the internal and external characteristics of the axial area-virgae-striae complex, central area, apical pore fields and differences among valves of the same frustule, in addition to the traditional valve shape and morphometric features.


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<p>Van de Vijver, B., Alexson, E.E., Reavie, E.D., Straub, F., Steinn Jónsson, G. &amp; Ector, L. (2021a) Analysis of the type of <em>Synedra acus</em> var. <em>ostenfeldii</em> (Bacillariophyta) and its transfer to the genus <em>Fragilaria</em>. <em>Bottany Letters</em> 168: 85–95.&nbsp;</p>
<p>Van de Vijver, B., Hürlimann, J., Williams, D.M., Levkov, Z., Wetzel, C.E. &amp; Ector, L. (2021b) <em>Fragilaria subrecapitellata</em> (Fragilariaceae, Bacillariophyta), a new diatom species from Switzerland. <em>Diatom Research</em> 36: 119–131.&nbsp;</p>
<p>Van de Vijver, B., Hürlimann, J., Potapova, M.P., Bahls, L., Ballings, P., Levkov, Z., Kusber, W-H. &amp; Ector, L. (2021c) Observations and typification of <em>Fragilaria cyclopum</em> (Brutschy) Lange-Bertalot (Fragilariaceae, Bacillariophyta). <em>Notulae Algarum</em> No. 204.</p>
<p>Van de Vijver, B., Williams, D.M., Schuster, T.M., Kusber, W-H., Cantonati, M., Wetzel, C.E. &amp; Ector, L. (2022) Analysis of the <em>Fragilaria rumpens</em> complex (Fragilariaceae, Bacillariophyta) with the description of two new species. <em>Fottea</em> 22: 93–121.&nbsp;</p>
<p>Wengrat, S., Morales, E.A., Wetzel, C.E., Almeida, P.D., Ector, L. &amp; Bicudo, D.C. (2016) Taxonomy and ecology of <em>Fragilaria billingsii</em> <em>sp. nov.</em> and analysis of type material of <em>Synedra rumpens</em> var. <em>fusa</em> (Fragilariaceae, Bacillariophyta) from Brazil. <em>Phytotaxa</em> 270: 191–202.&nbsp;</p>
<p>Wetzel, C.E. &amp; Ector, L. (2015) Taxonomy and ecology of <em>Fragilaria microvaucheriae</em> <em>sp. nov.</em> and comparison with the type materials of <em>F. uliginosa</em> and <em>F. vaucheriae</em>. <em>Cryptogamie, Algologie</em> 36: 271–289.&nbsp;</p>
<p>Williams, D.M. (1986) Comparative morphology of some species of <em>Synedra</em> with a new definition of the genus. <em>Diatom Research</em> 1: 131–152.&nbsp;</p>
<p>Williams, D.M. (2011) <em>Synedra</em>, <em>Ulnaria</em>: definitions and descriptions – a partial resolution. <em>Diatom Research</em> 26: 149–153.&nbsp;</p>
<p>Williams, D.M. (2019) Studies on type material from Kützing´s diatom collection I: <em>Synedra vitrea</em> Kützing, with comments on <em>Ulnaria fragilariaeformis</em> (F.E. Fritsch and M.F. Rich) D.M. Williams, nov. stat. et nov. comb. and <em>Ulnaria undulata</em> (Rabenhorst) D.M. Williams, nov. stat. et nov. comb. <em>Botanical Letters</em> 167: 70–85.&nbsp;</p>
<p>Williams, D.M. &amp; Round, F.E. (1988 “1987”) Revision of the genus <em>Fragilaria</em>. <em>Diatom Research </em>2: 267–288.&nbsp;</p>
<p>Williams, D.M. &amp; Van de Vijver, B. (2021) Studies on type material from Kützing´s diatom collection III: <em>Synedra splendens</em> (Kütz.) Kütz., <em>Synedra aequealis</em> (Kütz.) Kütz. and a note on <em>Synedra obtusa</em> W.Sm. <em>Fottea</em> 21: 164–179.&nbsp;</p>