New species of osmundaceous fertile leaves from the upper Triassic of Argentina
A new species of <i>Osmundopsis</i> Harris is described based on several impression-compression fossils from the upper section of the Potrerillos Formation (Uspallata Group) at Cerro Cacheuta Hill, Mendoza Province, Argentina. <i>Osmundopsis zunigai</i> sp. Nov. is characteri...
| Autores: | , , , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Argentina |
| Recursos: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/96805 |
| Acesso em linha: | http://sedici.unlp.edu.ar/handle/10915/96805 |
| Access Level: | acceso abierto |
| Palavra-chave: | Paleontología Ciencias Naturales Carnian Mendoza province Osmundaceae Osmundopsis Potrerillos formation |
| Resumo: | A new species of <i>Osmundopsis</i> Harris is described based on several impression-compression fossils from the upper section of the Potrerillos Formation (Uspallata Group) at Cerro Cacheuta Hill, Mendoza Province, Argentina. <i>Osmundopsis zunigai</i> sp. Nov. is characterized by having fertile pinnae with a slender striate rachis, bearing widely separate, opposite to subopposite short falcate pinnules with an entire margin, rounded apex, and a partially reduced lamina. The pinnules bear sporangia loosely disposed in clusters of four or five on the abaxial side. The sporangia are wedge-to heart-shaped, shortly stalked, with cells of the apical region thickened, and have a vertical dehiscence slit. The spores are trilete and laevigate. This is the first record of <i>Osmundopsis</i> in the Triassic of Argentina. The mutual occurrence or co-preservation of <i>Osmundopsis zunigai</i> sp. Nov. with sterile fronds of <i>Cladophlebis kurtzi</i> suggests the possibility that these species formed part of a dimorphic bipinnate frond. The diversity and geographic extent of fertile leaves of the <i>Osmunda</i> lineage in the early Late Triassic, with records in South Africa and Antarctica and now with this new taxon, support the idea of a moist mesothermal climatic belt in southern Gondwana. |
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