Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution
Cataphylls associated with the Middle Triassic stem genus Antarcticycas are described, and their impact on understanding cycad evolution is discussed. The cataphylls of Antarcticycas are triangular in outline and flattened adaxially with lateral flanges. The outer surfaces are covered with a ramentu...
Published in: | American Journal of Botany |
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crwiley:10.3732/ajb.93.5.724 2024-10-13T14:02:09+00:00 Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution Hermsen, Elizabeth J. Taylor, Thomas N. Taylor, Edith L. Stevenson, Dennis Wm. National Science Foundation 2006 http://dx.doi.org/10.3732/ajb.93.5.724 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.3732%2Fajb.93.5.724 https://onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.93.5.724 https://onlinelibrary.wiley.com/doi/full-xml/10.3732/ajb.93.5.724 http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.3732%2Fajb.93.5.724 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor American Journal of Botany volume 93, issue 5, page 724-738 ISSN 0002-9122 1537-2197 journal-article 2006 crwiley https://doi.org/10.3732/ajb.93.5.724 2024-09-17T04:46:39Z Cataphylls associated with the Middle Triassic stem genus Antarcticycas are described, and their impact on understanding cycad evolution is discussed. The cataphylls of Antarcticycas are triangular in outline and flattened adaxially with lateral flanges. The outer surfaces are covered with a ramentum of filamentous hairs, the epidermis is a single cell layer thick, and the ground tissue is parenchymatous with mucilage canals and sclereids. Vascular bundles form a distinct inverted omega‐shaped pattern characteristic of the Cycadales observed in petioles of extant species. The structures in Antarcticycas are interpreted as cataphylls based on overall morphology, presence of straight vascular strands in the cortex of the associated stem, and lack of fascicular cambia in the vascular bundles. Because much of the overall diversity of Cycadales is represented by fossils, integrating fossil taxa into explicit phylogenetic hypotheses is important for understanding cycad evolution. Therefore, character and minimum age mapping were performed on a phylogeny of extant and fossil taxa including Antarcticycas . The results suggest that major extant lineages of Cycadales had diverged by the Permian to Triassic and that certain synapomorphies for Cycadales had evolved by the Permian. Evidence of insect feeding on Antarcticycas suggests that associations between cycads and insects are ancient. Article in Journal/Newspaper Antarc* Wiley Online Library American Journal of Botany 93 5 724 738 |
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Wiley Online Library |
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crwiley |
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English |
description |
Cataphylls associated with the Middle Triassic stem genus Antarcticycas are described, and their impact on understanding cycad evolution is discussed. The cataphylls of Antarcticycas are triangular in outline and flattened adaxially with lateral flanges. The outer surfaces are covered with a ramentum of filamentous hairs, the epidermis is a single cell layer thick, and the ground tissue is parenchymatous with mucilage canals and sclereids. Vascular bundles form a distinct inverted omega‐shaped pattern characteristic of the Cycadales observed in petioles of extant species. The structures in Antarcticycas are interpreted as cataphylls based on overall morphology, presence of straight vascular strands in the cortex of the associated stem, and lack of fascicular cambia in the vascular bundles. Because much of the overall diversity of Cycadales is represented by fossils, integrating fossil taxa into explicit phylogenetic hypotheses is important for understanding cycad evolution. Therefore, character and minimum age mapping were performed on a phylogeny of extant and fossil taxa including Antarcticycas . The results suggest that major extant lineages of Cycadales had diverged by the Permian to Triassic and that certain synapomorphies for Cycadales had evolved by the Permian. Evidence of insect feeding on Antarcticycas suggests that associations between cycads and insects are ancient. |
author2 |
National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Hermsen, Elizabeth J. Taylor, Thomas N. Taylor, Edith L. Stevenson, Dennis Wm. |
spellingShingle |
Hermsen, Elizabeth J. Taylor, Thomas N. Taylor, Edith L. Stevenson, Dennis Wm. Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
author_facet |
Hermsen, Elizabeth J. Taylor, Thomas N. Taylor, Edith L. Stevenson, Dennis Wm. |
author_sort |
Hermsen, Elizabeth J. |
title |
Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
title_short |
Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
title_full |
Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
title_fullStr |
Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
title_full_unstemmed |
Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution |
title_sort |
cataphylls of the middle triassic cycad antarcticycas schopfii and new insights into cycad evolution |
publisher |
Wiley |
publishDate |
2006 |
url |
http://dx.doi.org/10.3732/ajb.93.5.724 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.3732%2Fajb.93.5.724 https://onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.93.5.724 https://onlinelibrary.wiley.com/doi/full-xml/10.3732/ajb.93.5.724 http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.3732%2Fajb.93.5.724 |
genre |
Antarc* |
genre_facet |
Antarc* |
op_source |
American Journal of Botany volume 93, issue 5, page 724-738 ISSN 0002-9122 1537-2197 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.3732/ajb.93.5.724 |
container_title |
American Journal of Botany |
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93 |
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5 |
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724 |
op_container_end_page |
738 |
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1812815221707767808 |