Abstract
During a survey of the diatom flora of the Adegoy River (Krasnodar Territory, Russia), an unknown Fragilaria species (Bacillariophyta) was found that could not be identified using the currently available literature and here we describe it as a new species. The morphology of Fragilaria irregularis sp. nov. was studied using light and scanning electron microscopy and compared to similar species including Fragilaria deformis, F. rinoi, F. septentrionalis and Fragilariforma bicapitata. It differed from these taxa in several characters. Most observed valves showed an irregular striation pattern, a feature not observed in other species. Other important differences include valve outline (linear with parallel margins) and stria density (7–14 in 10 µm, lower compared to all other species). The new taxon has a linear valve outline with parallel to weakly convex margins, subcapitate apices and a very irregular, coarse striation pattern.
References
<p>Bory de Saint-Vincent, J.B.G.M. (1822) Bacillarées. Dictionnaire Classique d’Histoire naturelle 2: 127–129.<br>Cantonati, M., Angeli, N. & Lange-Bertalot, H. (2019) Three new Fragilaria species (Bacillariophyta) from low-conductivity mountain freshwaters (Alps and Apennines). Phytotaxa 404 (6): 261–274. https://doi.org/10.11646/phytotaxa.404.6.5<br>Chudaev, D.A. & Gololobova, M.A. (2016) Diatomovye vodorosli ozera Glubokogo (Moskovskaya oblast). KMK, Moscow, 447 pp. [in Russian]<br>Chudaev, D., Jüttner, I. & Levkov, Z. (2021) The genus Navicula (Bacillariophyceae, Naviculaceae) from the valley of the Adegoy River (Krasnodar Territory, Russia) and description of two new species. Phytotaxa 494 (2): 208–218. https://doi.org/10.11646/phytotaxa.494.2.3<br>Cox, E.J. & Ross, R. (1981) The striae of pennate diatoms. In: Ross, R. (Ed.) Proceedings of the 6th Symposium on Recent and Fossil Diatoms. Koenigstein, O. Koeltz, pp. 267–278.<br>Delgado, C., Novais, M.H., Blanco, S. & Almeida, S.F.P. (2015) Examination and comparison of Fragilaria candidagilae sp. nov. with type material of Fragilaria recapitellata, F. capucina, F. perminuta, F. intermedia and F. neointermedia (Fragilariales, Bacillariophyceae). Phytotaxa 231 (1): 1–18.https://doi.org/10.11646/phytotaxa.231.1.1<br>Delgado, C., Novais, M.H., Blanco, S. & Almeida, S.F.P. (2016) Fragilaria rinoi sp. nov. (Fragilariales, Fragilariophyceae) from periphytic river samples in Central Portugal. European Journal of Taxonomy 248: 1–16.http://doi.org/10.5852/ejt.2016.248<br>Desmazières, J.B.H.J. (1830) Plantes Cryptogames du nord de la France. Lille, nos. 451–500.<br>Elyashev, A.A. (1957) O prostom sposobe prigotovlenia vysokoprelomlyayushchei sredy dlya diatomovogo analiza. Trudy NII geologii Arktiki 4: 74–75. [in Russian]<br>Falasco, E., Bona, F., Badino, G., Hoffmann, L., Ector, L. (2009) Diatom teratological forms and environmental alterations: a review. Hydrobiologia 623: 1–35.<br>Genkal, S.I. & Jarushina, M.I. (2017) Noteworthy records of diatoms and a new species Fragilaria strelnikovae in waterbodies and water courses of the Yamal Peninsula (Russia). Novosti Sistematiki Nizshikh Rastenii 51: 12–22.<br>Hantzsch, C.A. (1860) Neue Bacillarien: Nitzschia vivax var. elongata, Cymatopleura nobilis. Hedwigia 2 (7): 1–40.<br>Heudre, D., Wetzel, C.A., Moreau, L., Van de Vijver, B. & Ector, L. (2019a) On the identity of the rare Fragilaria subconstricta (Fragilariaceae), with Fragilaria species forming ribbon-like colonies shortly reconsidered. Plant Ecology and Evolution 152 (2): 327–339. https://doi.org/10.5091/plecevo.2019.1619<br>Heudre, D., Wetzel, C.E., Moreau, L. & Ector, L. (2019b) Fragilaria drouotiana sp. nov.: a new epiphytic freshwater diatom species (Fragilariaceae, Bacillariophyta) in lakes of Northeastern France. Algological Studies 155: 1–13.https://dx.doi.org/10.1127/algol_stud/2018/0310<br>Hoff, U., Lange-Bertalot, H. & Diekmann, B. (2011) Fragilaria flexura sp. nov. (Bacillariophyceae)–A new freshwater diatom from a meso-oligotrophic mountain lake on the Kamchatka Peninsula, Russia. Nova Hedwigia 92 (3–4): 441–451. https://dx.doi.org/10.1127/0029-5035/2011/0092-0441<br>Hornemann, J.W. (1810) Icones plantarum sponte nascentium in Regnis Daniae Norvegiae, et in Ducatibus Slesvici et Holsatiae ad illustrandum opus de iisdem plantis, Regio jussu exarandum, Florae Danicae nomine inscriptum. Typis E.A.H. Mölleri, Hauniae. Vol. 8 (fasc. 22, 23, 24). pls. 1261–1440.<br>Kelly, M.G., Adams, C., Graves, A.C., Jamieson, J., Krokowski, J., Lycett, E.B., Murray-Bligh, J., Prichard, S. & Wilkins, C. (2001) The trophic diatom index: a user’s manual. Revised edition. Environment Agency, Bristol, 135 pp.<br>Kociolek, J.P., Blanco, S., Coste, M., Ector, L., Liu, Y., Karthick, B., Kulikovskiy, M., Lundholm, N., Ludwig, T., Potapova, M., Rimet, F., Sabbe, K., Sala, S., Sar, E., Taylor, J., Van de Vijver, B., Wetzel, C.E., Williams, D.M., Witkowski, A. & Witkowski, J. (2021) DiatomBase. Available from: http://www.diatombase.org (accessed 30 March 2021)<br>Kosterin, O.E. & Solovyev, V.I. (2017) Odonata found in mid-summer 2015 and 2016 at the north-westernmost Black Sea Coast of the Caucasus, with the first record of Cordulegaster picta Selys, 1854 in Russian Federation. International Dragonfly Fund–Report 107: 1–43.<br>Krammer, K. (1997) Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 1. Allgemeines und Encyonema Part. Bibliotheca Diatomologica 36: 1–382.<br>Krammer, K. & Lange-Bertalot, H. (1985) Naviculaceae Neue und wenig bekannte Taxa, neue Kombinationen und Synonyme sowie Bemerkungen zu einigen Gattungen. Bibliotheca Diatomologica 9: 1–230.<br>Krammer, K. & Lange-Bertalot, H. (1991) Bacillariophyceae, 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In: Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.) Süßwasserflora von Mitteleuropa. Bd. 2/3. Gustav Fischer Verlag, Stuttgart, Jena, pp. 1–576.<br>Krammer, K. & Lange-Bertalot, H. (2000) Bacillariophyceae, 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In: Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.) Süßwasserflora von Mitteleuropa. Bd. 2/3 (ed. 2). Spektrum Akademischer Verlag, Heidelberg, 1–599.<br>Kützing, F.T. (1833) Algarum aquae dulcis germanicarum Decas I. In commissis C.A. Schwetschkii et fil., Halis Saxonum, 24 pp.<br>Kützing, F.T. (1834). Synopsis diatomearum oder Versuch einer systematischen Zusammenstellung der Diatomeen. Linnaea 8: 529–620.<br>Kützing, F.T. (1844) Die Kieselschaligen Bacillarien oder Diatomeen. W. Köhne, Nordhausen, 152 pp.<br>Lyngbye, H.C. (1819) Tentamen Hydrophytologiae Danicae Continens omnia Hydrophyta Cryptogama Daniae, Holsatiae, Faeroae, Islandiae, Groenlandiae hucusque cognita, Systematice Disposita, Descripta et iconibus illustrata, Adjectis Simul Speciebus Norvegicis. Typis Schultzianis, Hafniae, 248 pp.<br>Mayer, A. (1917) Beiträge zur Diatomeenflora Bayerns. Part I, A. Bacillariales aus dem Fichtelgebirge und angrenzenden Gebieten. B. Bacillariales aus dem Bayrischen Walde. Denkschriften der Koniglich-Baierischen Botanischen Gesellschaft in Regensburg 13: 1–99.<br>Metzeltin D., Lange-Bertalot, H. & Soninkhishig, N. (2009) Diatoms in Mongolia. Iconographia Diatomologica 20: 3–686.<br>Novais, M.H., Almeida, S.F.P., Blanco, S. & Delgado, C. (2019) Morphology and ecology of Fragilaria misarelensis sp. nov. (Bacillariophyta), a new diatom species from southwest of Europe. Phycologia 58 (2): 128–144. https://doi.org/10.1080/00318884.2018.1524245<br>Østrup, E. (1910) Diatoms from North-East Greenland. (Part 1. Marine Diatoms. Part 2. Freshwater Diatoms). Meddelelser om Groenland 43: 199–256.<br>Petersen, J.B. (1938) Fragilaria intermedia-Synedra vaucheriae ?. Botaniska Notiser 1938 (1–3): 164–170.<br>Rabenhorst, L. (1853) Die Süsswasser-Diatomaceen (Bacillarien.): für Freunde der Mikroskopie. Eduard Kummer, Leipzig, 72 pp.<br>Ross, R., Cox, E.J., Karayeva, N.I., Mann, D.G., Paddock, T.B.B., Simonsen, R. & Sims, P.A. (1979) An amended terminology for the siliceous components of the diatom cell. Nova Hedwigia, Beiheft 64: 513–533.<br>Round, F.E. (1979) The classification of the genus Synedra. Nova Hedwigia, Beiheft 64: 135–146.<br>Round, F.E., Crawford, R.M. & Mann, D.G. (1990) The diatoms. Biology & Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.<br>Schmidt, A. (1902) Atlas der Diatomaceen-kunde. O.R. Reisland, Leipzig. Series V: Heft 59–60. pls 233–240.<br>Smith, W. (1856) A Synopsis of the British Diatomaceae; with Remarks on their Structure, Functions and Distribution; and Instructions for Collecting and Preserving Specimens. Vol. 2. John van Voorst, London, 107 pp.<br>Tuji, A. & Williams, D.M. (2006) Typification of Conferva pectinalis O. F. Müll. (Bacillariophyceae) and the identity of the type of an alleged synonym, Fragilaria capucina Desm. Taxon 55 (1): 193–199.<br>Van de Vijver, B. & Ector, L. (2020) Analysis of the type material of Synedra perminuta (Bacillariophyceae) with the description of two new Fragilaria species from Sweden. Phytotaxa 468 (1): 89–100.https://doi.org/10.11646/phytotaxa.468.1.5<br>Van de Vijver, B., Mertens, A. & Ector, L. (2020a) Analysis of the type material of Synedra deformis W.Sm. and Synedra vaucheriae var. deformis Grunow (Fragilariaceae, Bacillariophyta). Cryptogamie, Algologie 41 (13): 137–149.https://doi.org/10.5252/cryptogamie-algologie2020v41a13<br>Van de Vijver, B., Lundholm, N., Lange, C., Wetzel, C.E. & Ector, L. (2020b) Observations on the type material of Synedra vaucheriae var. septentrionalis Østrup (Fragilariaceae, Bacillariophyta) and its transfer to the genus Fragilaria. Notulae Algarum 157: 1–4.<br>Van de Vijver, B., Hürlimann, J., Williams, D.M., Wetzel, C.E. & Ector, L. (2021a) Type analysis of Fragilaria capucina f. lanceolata-baikali and Fragilaria capucina f. sublanceolata-baikali (Bacillariophyta, Fragilariaceae). Notulae Algarum 181: 1–5.<br>Van de Vijver, B., Hürlimann, J., Williams, D.M., Levkov, Z., Wetzel, C.E. & Ector, L. (2021b) Fragilaria subrecapitellata (Fragilariaceae, Bacillariophyta), a new diatom species from Switzerland. Diatom Research (in press). <br>Van de Vijver, B., Alexon, E.E., Reavie, E.D., Straub, F., Jónsson, G.S., Ector, L. (2021c) Analysis of the type of Synedra acus var. ostenfeldii (Bacillariophyta) and its transfer to the genus Fragilaria. Botany Letters 168 (1): 85–95.https://doi.org/10.1080/23818107.2020.1845973<br>Van Heurck, H. (1880) Synopsis des Diatomées de Belgique Atlas. Ducaju et Cie, Anvers. pls I–XXX.<br>Van Heurck, H. (1881) Synopsis des Diatomées de Belgique Atlas. Ducaju et Cie, Anvers. pls XXXI–LXXVII.<br>Wetzel, C.E. & Ector, L. (2015) Taxonomy and ecology of Fragilaria microvaucheriae sp. nov. and comparison with the type materials of F. uliginosa and F. vaucheriae. Cryptogamie, Algologie 36 (3): 271–289.https://doi.org/10.7872/crya/v36.iss3.2015.271<br>Williams, D.M. (1986) Comparative morphology of some species of Synedra Ehrenb. with a new definition of the genus. Diatom Research 1 (1): 131–152.<br>Williams, D.M. (2012) Diatoma moniliforme: commentary, relationships and an appropriate name. Nova Hedwigia, Beiheft 14: 255–261.<br>Williams, D.M. & Round, F.E. (1987) Revision of the genus Fragilaria. Diatom Research 2 (2): 267–288.<br>Williams, D.M. & Round, F.E. (1988) Fragilariforma, nom. nov., a new generic name for Neofragilaria Williams & Round. Diatom Research 3 (2): 265–267.</p>