First record of Protopodocarpoxylon Eckhold in the Upper Triassic of South America

New record of gymnospermic wood is described from the xyloflora of the Hilario Formation of the Sorocayense Group (San Juan, Argentina) belonging to the Upper Triassic. The analized specimen is identified as Protopodocarpoxylon araucarioides assigned to the Cheirolepidiaceae. It presents limits of d...

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Autores principales: Vallejos Leiz, Laura Soledad, Gnaedinger, Silvia Cristina, Crisafulli, Alexandra María Cristina
Formato: Artículo revista
Lenguaje:Español
Publicado: Facultad de Ciencias Exactas y Naturales y Agrimensura 2024
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Acceso en línea:https://revistas.unne.edu.ar/index.php/fce/article/view/7793
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Sumario:New record of gymnospermic wood is described from the xyloflora of the Hilario Formation of the Sorocayense Group (San Juan, Argentina) belonging to the Upper Triassic. The analized specimen is identified as Protopodocarpoxylon araucarioides assigned to the Cheirolepidiaceae. It presents limits of distinct growth rings, radial pits of the brachyoxylean type (=mixed type), uniseriate and biseriate tracheids, cross– fields with 1–2, 4 podocarpoid oculipores, uniseriate and partially biseriate uniseriate rays, axial parenchyma, and tangential pits. Argentina records of Cheirolepidiaceae are numerous for the Jurassic and Cretaceous and correspond to wood, leaf/reproductive structures and pollen grains. They are scarce for the Triassic, which is why this finding provides relevant information for the flora of Gondwana, since this is the first record for the Upper Triassic of South America. Growth ring analysis is consistent with a humid, seasonally dry subtropical climate. The false growth rings provide data on environmental disturbances that affected growth such as droughts.