Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada
The evolutionary history of diatoms is only constrained partially by the fossil record. The timing of several key events, such as initial colonization of freshwater habitats by marine taxa, remains poorly resolved. Numerous specimens of the genera Cyclotella, Discostella , and Puncticulata (Ochrophy...
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crwiley:10.3732/ajb.0800307 2024-09-15T18:26:38+00:00 Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada Wolfe, Alexander P. Siver, Peter A. National Science Foundation 2009 http://dx.doi.org/10.3732/ajb.0800307 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.3732%2Fajb.0800307 https://onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.0800307 https://onlinelibrary.wiley.com/doi/full-xml/10.3732/ajb.0800307 http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.3732%2Fajb.0800307 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor American Journal of Botany volume 96, issue 2, page 487-497 ISSN 0002-9122 1537-2197 journal-article 2009 crwiley https://doi.org/10.3732/ajb.0800307 2024-08-30T04:11:21Z The evolutionary history of diatoms is only constrained partially by the fossil record. The timing of several key events, such as initial colonization of freshwater habitats by marine taxa, remains poorly resolved. Numerous specimens of the genera Cyclotella, Discostella , and Puncticulata (Ochrophyta: Thalassiosirales) have been recovered in Middle Eocene lacustrine sediments from the Giraffe Pipe locality in the Northwest Territories, Canada. These diatoms extend the fossil record of the family Stephanodiscaceae to at least 40 million years before present (Ma) and thus provide a new evolutionary milepost for the thalassiosiroid diatoms, an important clade of centric diatoms with global representation in both marine and freshwater environments. The quality of the fossil material enables detailed investigations of areolae, fultoportulae, and rimoportulae, revealing direct morphological affinities with a number of extant taxa. These observations extend the antiquity of several characters of phylogenetic importance within the thalassiosiroid diatoms, including the fultoportula, and imply that the entire lineage is considerably older than prior constraints from the fossil record, as suggested independently by several recent molecular phylogenies. Article in Journal/Newspaper Northwest Territories Wiley Online Library American Journal of Botany 96 2 487 497 |
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Wiley Online Library |
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crwiley |
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English |
description |
The evolutionary history of diatoms is only constrained partially by the fossil record. The timing of several key events, such as initial colonization of freshwater habitats by marine taxa, remains poorly resolved. Numerous specimens of the genera Cyclotella, Discostella , and Puncticulata (Ochrophyta: Thalassiosirales) have been recovered in Middle Eocene lacustrine sediments from the Giraffe Pipe locality in the Northwest Territories, Canada. These diatoms extend the fossil record of the family Stephanodiscaceae to at least 40 million years before present (Ma) and thus provide a new evolutionary milepost for the thalassiosiroid diatoms, an important clade of centric diatoms with global representation in both marine and freshwater environments. The quality of the fossil material enables detailed investigations of areolae, fultoportulae, and rimoportulae, revealing direct morphological affinities with a number of extant taxa. These observations extend the antiquity of several characters of phylogenetic importance within the thalassiosiroid diatoms, including the fultoportula, and imply that the entire lineage is considerably older than prior constraints from the fossil record, as suggested independently by several recent molecular phylogenies. |
author2 |
National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Wolfe, Alexander P. Siver, Peter A. |
spellingShingle |
Wolfe, Alexander P. Siver, Peter A. Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
author_facet |
Wolfe, Alexander P. Siver, Peter A. |
author_sort |
Wolfe, Alexander P. |
title |
Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
title_short |
Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
title_full |
Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
title_fullStr |
Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
title_full_unstemmed |
Three extant genera of freshwater thalassiosiroid diatoms from Middle Eocene sediments in northern Canada |
title_sort |
three extant genera of freshwater thalassiosiroid diatoms from middle eocene sediments in northern canada |
publisher |
Wiley |
publishDate |
2009 |
url |
http://dx.doi.org/10.3732/ajb.0800307 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.3732%2Fajb.0800307 https://onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.0800307 https://onlinelibrary.wiley.com/doi/full-xml/10.3732/ajb.0800307 http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.3732%2Fajb.0800307 |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_source |
American Journal of Botany volume 96, issue 2, page 487-497 ISSN 0002-9122 1537-2197 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.3732/ajb.0800307 |
container_title |
American Journal of Botany |
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96 |
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2 |
container_start_page |
487 |
op_container_end_page |
497 |
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1810467140953702400 |