Plant Ecology and Evolution 152(2): 203-218, doi: 10.5091/plecevo.2019.1626
Homothallism, morphology and phylogenetic position of a new species of Sellaphora (Bacillariophyta), S. pausariae
expand article infoDavid G Mann‡, Aloisie Poulíčková§
‡ Royal Botanic Garden Edinburg, Edinburg, United Kingdom§ Univerzity Palackého, Olomouc, Czechoslovakia

Corresponding author: David G Mann ( d.mann@rbge.org.uk )

© David G. Mann, Aloisie Poulíčková.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Mann DG, Poulíčková A (2019) Homothallism, morphology and phylogenetic position of a new species of Sellaphora (Bacillariophyta), S. pausariae. Plant Ecology and Evolution 152(2): 203-218. https://doi.org/10.5091/plecevo.2019.1626
Open Access
Abstract

Background and aims – The eutrophic Blackford Pond in Edinburgh has already provided the holotypes of six other Sellaphora species. A further undescribed species is present and requires description and characterization.

Methods – Clones of the new species are characterized by light (LM) and scanning electron microscopy (SEM) and molecular phylogenetics (from a concatenated five-gene alignment of 18S rDNA, 28S rDNA, 23S rDNA, cox1 and rbcL, and a two-gene alignment of cox1 and rbcL).

Key results – Sellaphora pausariae sp. nov. is named in honour of Dr Eileen Cox (‘pausaria’ = a lady coxswain). In molecular phylogenies, small-celled Sellaphora species (‘minima’ and ‘seminulum’ morphologies) branch off at the base of Sellaphora, though nodes are not well supported. Species and demes previously classified in either “Navicula pupula” or “Navicula bacillum” group into three very well supported clades (numbered 1–3). Although appearing in LM and SEM like a smaller, more delicate version of S. obesa, S. pausariae (clade 1) is not closely related to S. obesa (clade 2). Features of Sellaphora pausariae not confirmed previously in any Sellaphora but possibly widespread are: (a) hymenes with pores arranged in a regular scatter; (b) a stepped mantle near the poles; and (c) a ‘primodominant’ girdle comprising a wide band 1, a segmental band 2, and two extremely thin bands at the abvalvar end of the girdle. Sellaphora pausariae is homothallic; a deficiency of interclonal pairings in two-clone mixtures is interpreted as reflecting the tendency of cells to mate with their immediate neighbours.

Conclusions – Morphologically, the new species can be differentiated from existing described species, though only problematically from some informally named demes. Molecularly, it is clearly characterized by the five genes sequenced. Girdle terminology needs expansion (e.g. to distinguish primodominant girdles from ‘graded’ ones, in which the bands gradually decrease in width and structural complexity from the valve outwards).

Keywords
Bacillariophyta, cox1, diatoms, rDNA, mating data, molecular systematics, new species, rbcL, Sellaphora, taxonomy

References

  • Ács É., Wetzel C.E., Buczkó K., Kiss K.T., Nagy K., Trábert Z., Földi A., Pozderka V., Werner P., Heudre D., Ector L. (2017) Biogeography and morphology of a poorly known Sellaphora species. Fottea 17: 57–64. https://doi.org/10.5507/fot.2016.021
  • De Decker S., Vanormelingen P., Pinseel E., Sefbom J., Audoor S., Sabbe K., Vyverman W. (2018) Incomplete reproductive isolation between genetically distinct sympatric clades of the pennate model diatom Seminavis robusta. Protist 169: 569–583. https://doi.org/10.1016/j.protis.2018.05.003
  • Droop S.J.M., Mann D.G., Lokhorst G.M. (2000) Spatial and temporal stability of demes in Diploneis smithii/D. fusca (Bacillariophyta) supports a narrow species concept. Phycologia 39: 527–546. https://doi.org/10.2216/i0031-8884-39-6-527.1
  • Edgar R.C. (2004) MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32: 1792–1797. https://doi.org/10.1093/nar/gkh340
  • Evans K.M., Mann D.G. (2009) A proposed protocol for nomenclaturally effective DNA barcoding of microalgae. Phycologia 48: 70–74. https://doi.org/10.2216/08-70.1
  • Evans K.M., Wortley A.H., Mann D.G. (2007) An assessment of potential diatom “barcode” genes (cox1, rbcL, 18S and ITS rDNA) and their effectiveness in determining relationships in Sellaphora (Bacillariophyta). Protist 158: 349–364. https://doi.org/10.1016/j.protis.2007.04.001
  • Evans K.M., Wortley A.H., Simpson G.E., Chepurnov V.A., Mann D.G. (2008) A molecular systematic approach to explore diversity within the Sellaphora pupula species complex (Bacillariophyta). Journal of Phycology 44: 215–231. https://doi.org/10.1111/j.1529-8817.2007.00454.x
  • Falasco E., Blanco S., Bona F., Gomà J., Hlúbiková D., Novais M.H., Hoffmann L., Ector L. (2009) Taxonomy, morphology and distribution of the Sellaphora stroemii complex (Bacillariophyceae). Fottea 9: 243–256. https://doi.org/10.5507/fot.2009.025
  • Guiry M.D., Guiry G.M. (2018) AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Available from http://www.algaebase.org [accessed 1 Aug. 2018].
  • Hustedt F. (1930) Bacillariophyta. In: Pascher A. (ed.) Die Süsswasser-Flora Mitteleuropas, vol. 10 (ed. 2). Jena, G. Fischer.
  • Hustedt F. (1961) Die Kieselalgen Deutschlands, Österreichs und der Schweiz unter Berücksichtigung der übrigen Länder Europas sowie der angrenzenden Meeresgebiete. In: Dr L. Rabenhorst’s Kryptogamenflora von Deutschland, Österreich und der Schweiz, vol. 7(3:1): 1–160. Leipzig, Akademische Verlagsgesellschaft.
  • Kelly M., Boonham N., Juggins S., Kille P., Mann D., Pass D., Sapp M., Sato S., Glover R. (2018) A DNA based diatom metabarcoding approach for Water Framework Directive classification of rivers. SC140024/R. Bristol, Environment Agency.
  • Krammer K., Lange-Bertalot H. (1986) Bacillariophyceae 1. Teil: Naviculaceae. In: Ettl H., Gerloff J., Heynig H., Mollenhauer D. (eds) Süsswasserflora von Mitteleuropa, 2/1: 1–876. Stuttgart & New York, G. Fischer.
  • Kumar S., Stecher G., Tamura K. (2016) MEGA7: Molecular Evolutionary Genetics Analysis version 7.0 for bigger datasets. Molecular biology and evolution 33: 1870–1874. https://doi.org/10.1093/molbev/msw054
  • Letunic I., Bork P. (2016) Interactive tree of life (iTOL) v3: an online tool for the display and annotation of phylogenetic and other trees. Nucleic Acids Research 44(W1): W242–W245. https://doi.org/10.1093/nar/gkw290
  • Liu B., Williams D.M., Ou Y. (2017) Adlafia sinensis sp. nov. (Bacillariophyceae) from the Wuling Mountain Area, China, with reference to the structure of its girdle bands. Phytotaxa 298: 43–54. https://doi.org/10.11646/phytotaxa.298.1.4
  • Liu B., Williams D.M., Liu Q. (2018) A new species of Cymbella (Cymbellaceae, Bacillariophyceae) possessing valve with both uniseriate and biseriate striae. Phytotaxa 344: 39–46. https://doi.org/10.11646/phytotaxa.344.1.5
  • Lu J., Sun C., Wang J. (2015) Mechanical simulation of a diatom frustule structure. Journal of Bionic Engineering 12: 98–108.
  • Mann D.G. (1981) Sieves and flaps: siliceous minutiae in the pores of raphid diatoms. In: Ross R. (ed.) Proceedings of the 6th Symposium on Recent and Fossil Diatoms: 279–300. Koenigstein, O. Koeltz.
  • Mann D.G. (1989b) The species concept in diatoms: evidence for morphologically distinct, sympatric gamodemes in four epipelic species. Plant Systematics and Evolution 164: 215–237.
  • Mann D.G. (2008) The genus Sellaphora: an addition and corrections. Fottea 8: 117–119.
  • Mann D.G., Vanormelingen P. (2013) An inordinate fondness? The number, distributions and origins of diatom species. Journal of Eukaryotic Microbiology 60: 414–420. https://doi.org/10.1111/jeu.12047
  • Mann D.G., Chepurnov V.A., Droop S.J.M. (1999) Sexuality, incompatibility, size variation, and preferential polyandry in natural populations and clones of Sellaphora pupula (Bacillariophyceae). Journal of Phycology 35: 152–170. https://doi.org/10.1046/j.1529-8817.1999.3510152.x
  • Mann D.G., McDonald S.M., Bayer M.M., Droop S.J.M., Chepurnov V.A., Loke R.E., Ciobanu A., Du Buf J.M.H. (2004) Morphometric analysis, ultrastructure and mating data provide evidence for five new species of Sellaphora (Bacillariophyceae). Phycologia 43: 459–482.
  • Mann D.G., Thomas S.J., Evans K.M. (2008) Revision of the diatom genus Sellaphora: a first account of the larger species in the British Isles. Fottea 8: 15–78.
  • Mann D.G., Evans K.M., Chepurnov V.A., Nagai S. (2009) Morphology and formal description of Sellaphora bisexualis, sp. nov. (Bacillariophyta). Fottea 9: 199–209. https://doi.org/10.5507/fot.2009.021
  • Mann D.G., Poulíčková A., Sato S., Evans K.M. (2011) Scaly incunabula, auxospore development, and girdle polymorphism in Sellaphora marvanii sp. nov. (Bacillariophyceae). Journal of Phycology 47: 1368–1378. https://doi.org/10.1111/j.1529-8817.2011.01058.x
  • Mereschkowsky C. (1902) On Sellaphora, a new genus of diatoms. Annals and Magazine of Natural History, series 7, 9: 185–195.
  • Metzeltin D., Lange-Bertalot H. (2002) Diatoms from the “Island Continent” Madagascar. Iconographia diatomologica 11: 1–286.
  • Metzeltin D., Lange-Bertalot H., Soninkhishig N. (2009) Diatoms in Mongolia. Iconographia diatomologica 20: 3–686.
  • Müller O. (1910) Bacillariaceen aus dem Nyassalande und einigen benachbarten Gebieten. IV. Engler’s Botanische Jahrbücher 45: 69–122.
  • Ognjanova-Rumenova N. (2005) Upper Neogene siliceous microfossils from Pelagonia Basin (Balkan Peninsula). Geologica carpathica 56: 347–58.
  • Potapova M., Charles D.F. (2004) Potential use of rare diatoms as environmental indicators in U.S.A. rivers. In: Poulin M. (ed.) Proceedings of the 17th International Diatom Symposium: 281–295. Bristol, Biopress Limited.
  • Potapova M., Ponader K. (2008) New species and combinations in the diatom genus Sellaphora (Sellaphoraceae) from the Southeastern United States. Harvard Papers in Botany 13: 171–181.
  • Poulíčková A., Špačková J., Kelly M.G., Duchoslav M., Mann D.G. (2008) Ecological variation within Sellaphora species complexes (Bacillariophyceae) – specialists or generalists? Hydrobiologia 614: 373–386. https://doi.org/10.1007/s10750-008-9521-y
  • Poulíčková A., Sato S., Evans K.M., Chepurnov V.A., Mann D.G. (2015) Repeated evolution of uniparental reproduction in Sellaphora (Bacillariophyceae). European Journal of Phycology 50: 62–79. https://doi.org/10.1080/09670262.2014.985259
  • Poulíčková A., Kollár J., Hašler P., Dvořák P., Mann D.G. (2019) A new species Pinnularia lacustrigibba sp. nov. within the Pinnularia subgibba group (Bacillariophyceae). Diatom Research 33: 273–282. https://doi.org/10.1080/0269249X.2018.1513869
  • Round F.E., Crawford R.M., Mann D.G. (1990) The diatoms. Biology and morphology of the genera. Cambridge, Cambridge University Press.
  • Stosch H.A. von (1975) An amended terminology of the diatom girdle. Nova Hedwigia, Beiheft 53: 1–28.
  • Trobajo R., Rovira L., Ector L., Wetzel C.E., Kelly M., Mann D.G. (2013) Morphology and identity of some ecologically important small Nitzschia species. Diatom Research 28: 37–59.
  • Vanormelingen P., Evans K.M., Chepurnov V.A., Vyverman W., Mann D.G. (2013) Molecular species discovery in the diatom Sellaphora and its congruence with mating trials. Fottea 13: 133–148. https://doi.org/10.5507/fot.2013.012
  • Vasselon V., Rimet F., Tapolczai K., Bouchez A. (2017) Assessing ecological status with diatoms DNA metabarcoding: Scaling-up on a WFD monitoring network (Mayotte island, France). Ecological Indicators 82: 1–12. https://doi.org/10.1016/j.ecolind.2017.06.024
  • Wetzel C.E., Ector L., Van de Vijver B., Compère P., Mann D.G. (2015) Morphology, typification and critical analysis of some ecologically important small naviculoid species (Bacillariophyta). Fottea 15: 203–234. https://doi.org/10.5507/fot.2015.020
  • Witkowski A., Barka F., Mann D.G., Li C., Weisenborn J.L.F., Ashworth M.P., Kurzydłowski K.J., Zgłobicka I., Dobosz S. (2014) Description of Biremis panamae sp. nov., a new diatom species from the marine littoral, with an account of the phylogenetic position of Biremis D.G. Mann et E.J. Cox (Bacillariophyceae). PLoS ONE 9: e114508. https://doi.org/10.1371/journal.pone.0114508