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Type: Article
Published: 2022-09-30
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Descriptions of three new diatom species in the genus Eunotia (Eunotiaceae, Bacillariophyta) from the Eocene Arctic

Connecticut College, Botany Department, New London, CT, U.S.A. 06320
Connecticut College, Botany Department, New London, CT, U.S.A. 06320
Connecticut College, Botany Department, New London, CT, U.S.A. 06320
acidic ecology freshwater Giraffe Pipe new species raphe Algae

Abstract

Eunotia is the largest and most diverse genus within the family Eunotiaceae, a primarily freshwater group of diatoms often found in dilute, acidic and humic-stained environments. Species in this genus are characterized by being asymmetric along their apical axis, symmetric about the transapical axis, and with a simple and reduced raphe system situated largely on the mantle and restricted to the apical ends of the valve. In addition, Eunotia taxa have one or more rimoportula per valve, usually close to the apex. Because of their reduced raphe system, coupled with the presence of rimoportulae, Eunotia and its relatives are often viewed as the oldest lineage of raphe-bearing diatoms. To date, the oldest remains of Eunotia species have been reported from the early to middle Eocene, including from the Giraffe Pipe locality, an ancient Eocene fossil site located in northern Canada near the Arctic Circle. Rocks from this site contain a large and diverse assemblage of Eunotia taxa. The purpose of this study is to begin to characterize this assemblage with descriptions of three new species, Eunotia giraffensis sp. nov., E. petasum sp. nov. and E. pseudonaegelii sp. nov. The new species, representing the longest specimens found at the Giraffe Pipe locality, each possess characteristics common to Eunotia making them easily assigned to this genus. Because the Eunotia lineage was well established by the early part of the Eocene, it is likely to be significantly older.

References

<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Alles, E., Nörpel-Schempp, M. &amp; Lange-Bertalot, H. (1991) Zur systematic und Ökologie charakteristischer <em>Eunotia</em>-Arten (Bacillariophyceae) in elektrolytarmen Bachoberläufen. <em>Nova Hedwigia</em> 53: 171–213.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Ambwani, K., Sahni, A. &amp; Dutta, D. (2003) Oldest known non-marine diatoms (<em>Aulacoseira</em>) from the uppermost Cretaceous Deccan Intertrappean beds and Lameta Formation of India. <em>Revue de Micropaleontologie</em> 46: 67–71. https://doi.org/10.1016/S0035-1598(03)00011-4</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Barber, A., Siver, P.A. &amp; Karis, W. (2013) Euglyphid testate amoebae (Rhizaria: Euglyphida) from an Arctic Eocene waterbody: Evidence of evolutionary stasis in plate morphology for over 40 Million years. <em>Protist</em> 164: 541–555. https://doi.org/10.1016/j.protis.2013.05.001</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Benson, M.E., Kociolek, J.P., Spaulding, S.A. &amp; Smith, D.A. (2012) Pre-Neogene non-marine diatom biochronology with new data from the late Eocene Florissant Formation of Colorado, USA. <em>Stratigraphy</em> 9: 131–152.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Bourrelly, P. &amp; Manguin, É. (1952) <em>Algues d’eau douce de la Guadeloupe et dépendances: recueillies par la Mission P. Allorge en 1936</em>. Société d’Édition d’Enseignement Superiéur, Paris, 282 pp.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Brown, J.W. &amp; Sorhannus, U. (2010) A molecular genetic timescale for the diversification of autotrophic Stramenopiles (Ochrophyta): substantive underestimation of putative fossil ages. <em>Plos One </em>5 (9): e12759. https://doi.org/10.1371/journal.pone.0012759</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Burliga<span lang="en-GB">,</span> A.L., Torgan, L.C. &amp; Beaumord, A.C. (2007) <em>Eunotia ariengae </em>sp. nov., an epilithic diatom from Brazilian Amazon. <em>Diatom Research </em>22: 247–253. https://doi.org/10.1080/0269249X.2007.9705714</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Camburn, K.E. &amp; Charles, D.F. (2000) <em>Diatoms of low-alkalinity lakes in the northeastern United States</em>. Special Publication 18: The Academy of Natural Sciences of Philadelphia, Scientific Publications, Philadelphia. 152 pp. </span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Chacón-Baca, E., Heraldi-Campesi, H., Cevallos-Ferriz, S.R.S., Knoll, A.H. &amp; Golubic, S. (2002) 70 Ma nonmarine diatoms from northern Mexico. <em>Geology</em> 30: 279–281.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Cleve [Cleve-Euler], A. (1895) On recent freshwater diatoms from Lule Lappmark in Sweden. <em>Bihang till Kongliga Svenska Vetenskaps-Akademiends Handlingar</em> 21: 1–44.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Conrad, W. (1938) Notes portistologiques 1. <em>Mallomonas lychenensis</em>, n. sp. <em>Bulletin du Musée Royal d’Histoire Naturelle de Belgique </em>14 (20): 1–4.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Costa, L.F., Wetzel, C.E., Lange-Bertalot, H., Ector, L. &amp; Bicudo, D.C. (2017) Taxonomy and ecology of <em>Eunotia</em> species (Bacillariophyta) in southeastern Brazilian reservoirs. <em>Bibliotheca Diatomologica</em> 64: 1–302. </span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Ehrenberg, C.G. (1837) Über ein aus fossilen Infusorien bestehendes, 1832 zu Brod verbacknes Bergmehl von den Grenzen Lapplands <em>In</em>: Schweden.&nbsp;<em>Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königl. Preuß. Akademie der Wissenschaften zu Berlin</em>&nbsp;1837: 43–45.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Farooqui, A., Aggarwal, N., Jha, N. &amp; Phartiyal, B. (2015) Oldest record of freshwater diatom frustules in tests of Permian thecamoebians: faithfulness of sedimentary record. <em>International Journal of Current Microbiology and Applied Sciences</em> 4: 472–485.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Flower, R.J. (1989) A new variety of <em>Tabellaria</em> <em>binalis</em> (Ehrenb.) Grunow from several acid lakes in the U.K. <em>Diatom Research</em> 4: 21–23. https://doi.org/10.1080/0269249X.1989.9705048</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Gaiser, E.E. &amp; Johansen, J. (2000) Freshwater diatoms from Carolina bays and other isolated wetlands on the Atlantic coastal plain of South Carolina, U.S.A., with descriptions of seven taxa new to science. <em>Diatom Research</em> 15: 75–130. http://dx.doi.org/10.1080/0269249X.2000.9705487</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Guiry, M.D. &amp; Guiry, G.M. (2022) AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Available from: https://www.algaebase.org (accessed 28 February 2022).</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Kingston, J.C. (2003) Araphid and monoraphid diatoms. <em>In</em>: Wehr, J.D. &amp; Sheath, R.G. (Eds.) <em>Freshwater Algae of North America</em>. Academic Press, New York, pp. 595–636.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Kociolek, J.P. &amp; Rhode, K. (1998) Raphe vestiges in “<em>Asterionella</em>” species from Madagascar: evidence for a polyphyletic origin of the araphid diatoms? <em>Cryptogamie Algologie</em> 19: 57–74.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Kützing, F.T. (1849) <em>Species algarum</em>. Lipsiae [Leipzig]: F.A. Brockhaus. pp. [i]–vi, [1]–922.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Lange-Bertalot, H. &amp; Metzeltin, D. (1996) Indicators of oligotrophy – 800 taxa representative of three ecologically distinct lake types, carbonate buffered – oligodystrophic – weakly buffered soft water. <em>In</em>: Lange-Bertalot, H. (ed.) <em>Iconographia Diatomologica</em> 2: 1–390.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Lange-Bertalot, H. &amp; Metzeltin, D. (2009) A dystrophic mountain lake in Panama – hot spot of new and rare neotropical diatoms. <em>Nova Hedwigia, Beiheft</em> 135: 137–165.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Lange-Bertalot, H., Bak, M. &amp; Witkowski, A. (2011) <em>Eunotia</em> and some related genera. <em>In</em>: Lange-Bertalot, H. (ed.) <em>Diatoms of Europe</em>. Vol. 3. Koeltz Scientific Books, Königstein, pp. 1–358.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Lewis, F.W. (1864) On some new and singular intermediate forms of Diatomaceae.&nbsp;<em>Proceedings of the Academy of Natural Sciences of Philadelphia</em>&nbsp;15: 336–346.&nbsp;</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Lohman, K.E. &amp; Andrews, G.W. (1968) Late Eocene nonmarine diatoms from the Beaver Divide Area, Fremont County, Wyoming. <em>U. S. Geological Survey Professional Paper</em> 593-E: 24.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Mann, D.G. (1984) An ontogenetic approach to diatom systematic. <em>In</em>: Mann, D.G. (Ed.) <em>Proceedings of the 7</em><sup><em>th</em></sup><em> International Symposium on Living and Fossil Diatoms.</em> Koeltz Scientific Books, Königstein, pp. 131–141.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Marsicano, L.J. &amp; Siver, P.A. (1993) A paleolimnological assessment of lake acidification in five Connecticut lakes. <em>Journal of Paleolimnology</em> 9: 209–221. https://doi.org/10.1007/BF00677214</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Mayama, S. &amp; Kobayasi, H. (1991) Observations of <em>Eunotia</em> <em>arcus</em> Ehr., type species of the genus <em>Eunotia</em> (Bacillariophyceae). <em>Japanese Journal of Phycology</em> 39: 131–141.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Medlin, L.K. (2016) Evolution of the diatoms: major steps in their evolution and a review of the supporting molecular and morphological evidence. <em>Phycologia</em> 55: 79–103. https://doi.org/10.2216/15-105.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Medlin, L.K. &amp; Kaczmarska, I. (2004) Evolution of the diatoms: V. Morphological and cytological support for the major clades and a taxonomic revision. <em>Phycologia </em>43: 245–270. https://doi.org/10.2216/i0031-8884-43-3-245.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Melo, S., Torgan, L.C. &amp; Raupp, S.V. (2010) <em>Actinella</em> species (Bacillariophyta) from an Amazon blackwater floodplain lake (Amazonas-Brazil). <em>Acta Amazonica</em> 40: 269–274. https://doi.org/10.1590/S0044-59672010000200004</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Metzeltin, D. &amp; Lange-Bertalot, H. (1998) Tropical diatoms of South America I. <em>Iconographia Diatomologica</em> 5: 1–695.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Metzeltin, D. &amp; Lange-Bertalot, H. (2002) Diatoms from the “Island Continent” Madagascar<em>. In</em>: Lange-Bertalot, H. (ed.) <em>Iconographia Diatomologica</em> 11: 1–286. </span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Metzeltin, D. &amp; Lange-Bertalot, H. (2007) Tropical diatoms of South America II. <em>Iconographia Diatomologica </em>18: 1–877.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Migula, W. (1905) <em>Kryptogamen-Flora von Deutschland, Deutsch-Österreich und der Schweiz. Band II. Algen. 1. Teil. Cyanophyceae, Diatomaceae, Chlorophyceae</em>. Berlin: H. Bergmühler, 208 pp. </span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Novitski, L. &amp; Kociolek, J.P. (2005) Preliminary light and scanning electron microscope observations of marine fossil <em>Eunotia</em> species with comments on the evolution of the genus <em>Eunotia</em>. <em>Diatom Research</em> 20: 137–143. http://dx.doi.org/10.1080/0269249X.2005.9705623</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Pisera, A., Siver, P.A. &amp; Wolfe, A.P. (2013) A first account of freshwater Potamolepid (Demospongiae, Spongillina, Potamolepidae) from the Middle Eocene: Biogeographic and paleoclimatic implications. <em>Journal of Paleontology</em> 87: 373–378. https://doi.org/10.1666/12-079.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Pisera, A. Manconi, R., Siver, P.A. &amp; Wolfe, A.P. (2016) The sponge genus <em>Ephydatia</em> from the high-latitude middle Eocene: environmental and evolutionary significance. <em>Paläontologische Zeitschrift</em> 90: 673–680. https://doi.org/10.1007%2Fs12542-016-0328-2</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Ross, R., Cox, E.J., Karayeva, N.I., Mann, D.G., Paddock, T.B.B., Simonsen, R. &amp; Sims, P.A. (1979) An amended terminology for the siliceous components of the diatom cell. <em>Nova Hedwigia, Beiheft </em>64: 513–533.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Round, F.E., Crawford, R.M. &amp; Mann, D.G. (1990) <em>The diatoms. Biology and morphology of the genera</em>. Cambridge University Press, Cambridge, 747 pp.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Sabbe, K., Vanhoutte, K., Lowe, R.L., Bergey, E.A., Biggs, B.J.F., Francoeur, S., Hodgson, D. &amp; Vyverman, W. (2001) Six new <em>Actinella </em>(Bacillariophyta) species from Papua New Guinea, Australia and New Zealand: further evidence for widespread diatom endemism in the Australasian region. <em>European Journal of Phycology</em> 36: 321–340.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siemińska, J. (2000) The discoveries of diatoms older than the Cretaceous. <em>In</em>: Witkowski, A. &amp; Siemińska, J. (Eds.) <em>The origin and early evolution of the diatoms: fossil, molecular and biogeographical approaches</em>. W. Szafer Institute of Botany, Polish Academy of Sciences, Cracow. pp. 55–74.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siemińska, J. &amp; Kwiecińska, B. (2000) The Proterozoic diatoms from the Przeworno marbles. <em>In</em>: Witkowski, A. &amp; J. Siemińska, J. (Eds.) <em>The origin and early evolution of the diatoms: fossil, molecular and biogeographical approaches.</em> W. Szafer Institute of Botany, Polish Academy of Sciences, Cracow, pp. 97–121.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Sims, P.A., Mann, D.G. &amp; Medlin, L.K. (2006) Evolution of the diatoms: insights from fossil, biological and molecular data. <em>Phycologia</em> 45: 361–402. https://doi.org/10.2216/05-22.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Singh, R.S., Stoermer, E.F. &amp; Kar, R. (2006) Earliest freshwater diatoms from the Deccan Intertrappean sediments of India. <em>Micropaleontology</em> 52: 545–551. http://dx.doi.org/10.2113/gsmicropal.52.6.545</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2013) <em>Synura cronbergiae</em> sp. nov, a new species described from two Paleogene maar lakes in northern Canada. <em>Nova Hedwigia</em> 97: 179–187. https://doi.org/10.1127/0029-5035/2013/0108</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2015) <em>Mallomonas</em> <em>schumachii</em> sp. nov., a fossil synurophyte bearing large scales described from an Eocene maar lake in Northern Canada. <em>Nova Hedwigia</em> 101: 285–298. http://dx.doi.org/10.1127/nova_hedwigia/2015/0270</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2018a) <em>Mallomonas</em> <em>aperturae</em> sp. nov. (Synurophyceae) reveals that the complex cell architecture observed on modern synurophytes was well established by the middle Eocene. <em>Phycologia</em> 57: 273–279. https://doi.org/10.2216/17-112.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2018b) <em>Mallomonas skogstadii </em>sp. nov. and <em>M</em>. <em>bakeri </em>sp. nov.: Two new fossil species from the middle Eocene representing extinct members of the section Heterospinae? <em>Cryptogamie, Algologie</em> 39: 511–524. https://dx.doi.org/10.7872/crya/v39.iss4.2018.511</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2019) An emended description of the freshwater araphid genus <em>Ambistria</em>: a rare diatom from North American Eocene localities. <em>Diatom Research</em> 34: 225–236. https://doi.org/10.1080/0269249X.2019.1691055</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. (2021) <em>Aulacoseira</em> <em>chockii</em> sp. nov., an early freshwater centric diatom from the Eocene bearing a unique morphology. <em>Diatom Research</em>. 36: 253–263. https://doi.org/10.1080/0269249X.2021.1982016</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Hamilton, P.B. (2011) Diatoms of North America: The Freshwater Flora of the Atlantic Coastal Plain. <em>Iconographia Diatomologica</em> 22: 1–920.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Skogstad, A. (2022) A first account of the heterotrophic eukaryote <em>Rabdiophrys</em> Rainer from the fossil record and description of a new species from an ancient Eocene Arctic freshwater lake. <em>European Journal of Protistology</em> 82: 12857. https://doi.org/10.1016/j.ejop.2021.125857</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Wolfe, A.P. (2005a) Eocene scaled chrysophytes with pronounced modern affinities. <em>International Journal of Plant Sciences</em> 166: 533–536.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Wolfe, A.P. (2005b) Scaled chrysophytes in Middle Eocene lake sediments from Northwestern Canada, including description of six new species. <em>Nova Hedwigia, Beiheft </em>128<em>:</em> 295–308.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Wolfe, A.P. (2007) <em>Eunotia</em> spp. (Bacillariophyceae) from Middle Eocene lake sediments and comments on the origin of the diatom raphe. <em>Canadian Journal of Botany </em>85: 83–90. https://dx.doi.org/10.1139/b06-143</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A. &amp; Wolfe, A.P. (2009) Tropical ochrophyte algae from the Eocene of Northern Canada: A biogeographic response to past global warming. <em>Palaios</em> 24: 192–198. https://dx.doi.org/10.2110/palo.2007-p07-077r</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Hamilton, P.B. &amp; Pelczar, J. (2009) New species of freshwater diatoms from acidic localities along the Atlantic Coastal Plain of the United States. <em>Botany</em> 87 (4): 408–427. https://doi.org/10.1139/B09-015</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Hamilton, P.B., Stachura-Suchoples, K. &amp; Kociolek, J.P. (2005) Diatoms of North America: The Freshwater Flora of Cape Cod<em>. Iconographia Diatomologica</em> 14: 1–463.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Wolfe, A.P. &amp; Edlund, M. (2010) Taxonomic descriptions and evolutionary implications of Middle Eocene pennate diatoms representing the extant genera <em>Oxyneis</em>, <em>Actinella</em> and <em>Nupela </em>(Bacillariophyceae). <em>Plant Ecology &amp; Evolution</em> 143: 340–351. https://dx.doi.org/10.5091/plecevo.2010.419</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Jo, B.Y., Kim, J.I., Shin, W., Lott, A.M. &amp; Wolfe, A.P. (2015) Assessing the evolutionary history of the class Synurophyceae (Heterokonta) using molecular, morphometric, and paleobiological approaches. <em>American Journal of Botany</em> 102: 1–21. https://doi.org/10.3732/ajb.1500004</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Velez, M., Cliveti, M. &amp; Binda, P. (2018) Early freshwater diatoms from the Upper Cretaceous Battle Formation in western Canada. <em>Palaios</em> 33: 1–10. https://doi.org/10.2110/palo.2018.045</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Siver, P.A., Lott, A.M. &amp; Torres, P. (2020) Abundance and distribution of testate amoebae bearing siliceous plates in freshwater lakes and ponds along the east coast of North America: Importance of water depth and pH. <em>Freshwater Science</em> 39: 791–803.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Sorhannus, U. (2004) Diatom phylogenetics inferred based on direct optimization of nuclear-encoded SSU r-RNA sequences. <em>Cladistics</em> 20: 487–497. https://doi.org/10.1111/j.1096-0031.2004.00034.x</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Sorhannus, U. (2007) A nuclear-encoded small-submit ribosomal RNA timescale for diatom evolution. <em>Marine Micropaleontology</em> 65: 1–12.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Werum, M. &amp; Lange-Bertalot, H. (2004) Diatoms in springs from Central Europe and elsewhere under the influence of hydrologeology and anthropogenic impacts. <em>Iconographia Diatomologica</em> 13: 3–417.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wetzel, C.E., Ector, L., Hoffmann, L., Lange-Bertalot, H. &amp; Bicudo, D.C. (2011) Two new periphytic <em>Eunotia</em> species from the neotropical Amazonian “black waters”, with a type analysis of <em>E</em>. <em>braunii</em>. <em>Diatom Research</em> 26: 135–146. https://dx.doi.org/10.1080/0269249X.2011.587644</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Williams, D.W. &amp; Reid, G. (2006) Fossils and the tropics, the Eunotiaceae (Bacillariophyta) expanded: a new genus for the Upper Eocene fossil diatom <em>Eunotia</em> <em>reedii</em> and the recent tropical marine diatom <em>Amphora</em> <em>reichardtiana. European Journal of Phycology</em> 41: 147–154. https://doi.org/10.1080/09670260600628564</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wolfe, A.P. &amp; Siver, P.A. (2009) Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada. <em>American Journal of Botany</em> 96: 487–497. https://dx.doi.org/10.3732/ajb.0800307</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wolfe, A.P., Edlund, M.B., Sweet, A.R. &amp; Creighton, S.D. (2006) A first account of organelle preservation in Eocene nonmarine diatoms: observations and paleobiological implications. <em>Palaios</em> 21: 298–304.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wolfe, A.P., Reyes, A.V., Royer, D.L., Greenwood, D.R., Doria, G., Gagen, M.H., Siver, P.A. &amp; Westgate, J.A. (2017) Middle Eocene CO<sub>2</sub> and climate reconstructed from the sediment fill of a subarctic kimberlite maar. <em>Geology</em> 45: 619–622. https://dx.doi.org/10.1130/G39002.1</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zanon, V. (1929) Diatomee triassiche. <em>Atti Academie Nuovi Lincei, Roma</em> 14: 289–307.</span></span></span></p>