Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology

Premise of the study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum . but compression fossil equisetaleans that are morphologically indistinguishable from extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mes...

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Autores principales: Channing, Alan, Zamuner, Alba Berta, Edwards, Dianne, Guido, Diego Martín
Formato: Articulo
Lenguaje:Inglés
Publicado: 2011
Materias:
Ciencias Naturales
Equisetites
Equisetum
fossil
geothermal wetland
hot spring
Late Jurassic
paleoecophysiology
silica
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/176750
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-176750
record_format dspace
spelling I19-R120-10915-1767502025-02-20T20:11:54Z http://sedici.unlp.edu.ar/handle/10915/176750 Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology Channing, Alan Zamuner, Alba Berta Edwards, Dianne Guido, Diego Martín 2011 2025-02-20T14:07:06Z en Ciencias Naturales Equisetites Equisetum fossil geothermal wetland hot spring Late Jurassic paleoecophysiology silica Premise of the study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum . but compression fossil equisetaleans that are morphologically indistinguishable from extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mesozoic initial diversifi cation. Methods: In situ samples of Equisetum thermale sp. nov. from the Upper Jurassic San Agust í n hot spring deposit were collected and studied with the use of polished blocks, thin sections, and light microscopy. Key results: Equisetum thermale exhibits all the morphological and anatomical characteristics of the extant crown group Equisetum . It shows a mixture of features present in the two extant subgenera, e.g., superfi cial stomata typical of subgenus Equisetum allied with infrequently ramifying stems typical of subgenus Hippochaete . This appears to ally E . thermale with the least derived extant species in the genus Equisetum bogotense (sister species to the two subgenera). Its association of hydromorphic and xeromorphic characters allowed it to grow as an emergent aquatic in physically and chemically stressed geothermally infl uenced wetlands, where it formed dense monospecifi c stands. Equisetum thermale , because it is preserved in situ with intact anatomy, provides clear paleoecological, biological, plus inferred paleoecophysiological evidence of adaptations known in extant species. Conclusions: As the earliest unequivocal member of the genus, E. thermale supports the hypothesis of a Mesozoic origin. Its inferred tolerance of a similar range of stresses (e.g., high salinity, alkalinity, and heavy metal concentrations) to that seen in extant Equisetum suggests early evolution and subsequent maintenance of ecophysiological innovations in the genus. Facultad de Ciencias Naturales y Museo Articulo Articulo http://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) application/pdf 680-697
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Naturales
Equisetites
Equisetum
fossil
geothermal wetland
hot spring
Late Jurassic
paleoecophysiology
silica
spellingShingle Ciencias Naturales
Equisetites
Equisetum
fossil
geothermal wetland
hot spring
Late Jurassic
paleoecophysiology
silica
Channing, Alan
Zamuner, Alba Berta
Edwards, Dianne
Guido, Diego Martín
Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
topic_facet Ciencias Naturales
Equisetites
Equisetum
fossil
geothermal wetland
hot spring
Late Jurassic
paleoecophysiology
silica
description Premise of the study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum . but compression fossil equisetaleans that are morphologically indistinguishable from extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mesozoic initial diversifi cation. Methods: In situ samples of Equisetum thermale sp. nov. from the Upper Jurassic San Agust í n hot spring deposit were collected and studied with the use of polished blocks, thin sections, and light microscopy. Key results: Equisetum thermale exhibits all the morphological and anatomical characteristics of the extant crown group Equisetum . It shows a mixture of features present in the two extant subgenera, e.g., superfi cial stomata typical of subgenus Equisetum allied with infrequently ramifying stems typical of subgenus Hippochaete . This appears to ally E . thermale with the least derived extant species in the genus Equisetum bogotense (sister species to the two subgenera). Its association of hydromorphic and xeromorphic characters allowed it to grow as an emergent aquatic in physically and chemically stressed geothermally infl uenced wetlands, where it formed dense monospecifi c stands. Equisetum thermale , because it is preserved in situ with intact anatomy, provides clear paleoecological, biological, plus inferred paleoecophysiological evidence of adaptations known in extant species. Conclusions: As the earliest unequivocal member of the genus, E. thermale supports the hypothesis of a Mesozoic origin. Its inferred tolerance of a similar range of stresses (e.g., high salinity, alkalinity, and heavy metal concentrations) to that seen in extant Equisetum suggests early evolution and subsequent maintenance of ecophysiological innovations in the genus.
format Articulo
Articulo
author Channing, Alan
Zamuner, Alba Berta
Edwards, Dianne
Guido, Diego Martín
author_facet Channing, Alan
Zamuner, Alba Berta
Edwards, Dianne
Guido, Diego Martín
author_sort Channing, Alan
title Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
title_short Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
title_full Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
title_fullStr Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
title_full_unstemmed Equisetum thermale sp. nov. (Equisetales) from the Jurassic San Agustín hot spring deposit, Patagonia: anatomy, paleoecology, and inferred paleoecophysiology
title_sort equisetum thermale sp. nov. (equisetales) from the jurassic san agustín hot spring deposit, patagonia: anatomy, paleoecology, and inferred paleoecophysiology
publishDate 2011
url http://sedici.unlp.edu.ar/handle/10915/176750
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