Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina

The Gran Chaco Americano is a large subtropical plain and one of the major biogeographic and morphostructural territories of South-America. Eastern Chaco is the wettest sector of the Gran Chaco and has heterogeneous en- vironments. It includes different types of woodlands and forests together wi...

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Autores principales: Contreras, Silvina Andrea, Robledo, Juan Manuel
Formato: Artículo
Lenguaje:Inglés
Publicado: Elsevier 2026
Materias:
Azolla
Salvinia
Massulae
Chaco region
Late Holocene
Bermejo river
Acceso en línea:http://repositorio.unne.edu.ar/handle/123456789/60110
Aporte de:
RIUNNE - Repositorio Institucional de la Universidad Nacional del Nordeste (UNNE) de Universidad Nacional del Nordeste
id I48-R184-123456789-60110
record_format dspace
spelling I48-R184-123456789-601102026-03-06T15:06:13Z Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina Contreras, Silvina Andrea Robledo, Juan Manuel Azolla Salvinia Massulae Chaco region Late Holocene Bermejo river The Gran Chaco Americano is a large subtropical plain and one of the major biogeographic and morphostructural territories of South-America. Eastern Chaco is the wettest sector of the Gran Chaco and has heterogeneous en- vironments. It includes different types of woodlands and forests together with savannahs, grasslands and wet- lands. These vegetation patterns have been proposed to be the result of the Quaternary alluvial plain dynamics and the intensive migration of the Chacoan main rivers. Fossil records-that show change-are scarce and most of them come from the Fidelidad Formation (late Holocene). This Formation is located on the Bermejo River natural levees near the Villa Escolar Town (Formosa Province, Argentina). Fern fossils discovered in this Formation correspond to heterosporous aquatic ferns (Salviniaceae). The impressions were assigned to Salvinia cf. minima Baker 1886. These correspond with orbicular to elliptical leaves, with a smooth margin, and both the apex and the base are rounded. The base bears a slightly developed petiole. The venation pattern is dichotomous with anastomoses forming areolas. Generally, four tubercles (trichome bases) per areola are observed. The massulae and spores correspond to Azolla cristata Kaulfuss 1824. The massulae are rounded, oval or kidney-shaped and have septate glochidia. Spores are trilete and spheroidal. The floating ferns Salvinia and Azolla are good indicators of open fresh-water or wetlands paleo-environments. Hence, the lower levels of the Fidelidad Formation are associated with mostly calm freshwater bodies such as rivers, streams or wetlands, which are closely related to the activity of the Bermejo River during the late Holocene. These aquatic fern fossils provide new insights into paleoenvironmental conditions and increase the paleontological richness of the Eastern Chaco. 2026-03-06T15:06:10Z 2026-03-06T15:06:10Z 2021 Artículo Contreras, Silvina Andrea y Robledo, Juan Manuel, 2021. Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina. Journal of South American Earth Sciences. Ámsterdam: Elsevier, vol. 109. p. 1-11. E-ISSN 1873‑0647. DOI https://doi.org/10.1016/j.jsames.2021.103273 http://repositorio.unne.edu.ar/handle/123456789/60110 eng https://doi.org/10.1016/j.jsames.2021.103273 openAccess http://creativecommons.org/licenses/by-nc-nd/2.5/ar/ application/pdf p. 1-11 application/pdf Elsevier Journal of South American Earth Sciences, 2021, vol. 109. p. 1-11.
institution Universidad Nacional del Nordeste
institution_str I-48
repository_str R-184
collection RIUNNE - Repositorio Institucional de la Universidad Nacional del Nordeste (UNNE)
language Inglés
topic Azolla
Salvinia
Massulae
Chaco region
Late Holocene
Bermejo river
spellingShingle Azolla
Salvinia
Massulae
Chaco region
Late Holocene
Bermejo river
Contreras, Silvina Andrea
Robledo, Juan Manuel
Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
topic_facet Azolla
Salvinia
Massulae
Chaco region
Late Holocene
Bermejo river
description The Gran Chaco Americano is a large subtropical plain and one of the major biogeographic and morphostructural territories of South-America. Eastern Chaco is the wettest sector of the Gran Chaco and has heterogeneous en- vironments. It includes different types of woodlands and forests together with savannahs, grasslands and wet- lands. These vegetation patterns have been proposed to be the result of the Quaternary alluvial plain dynamics and the intensive migration of the Chacoan main rivers. Fossil records-that show change-are scarce and most of them come from the Fidelidad Formation (late Holocene). This Formation is located on the Bermejo River natural levees near the Villa Escolar Town (Formosa Province, Argentina). Fern fossils discovered in this Formation correspond to heterosporous aquatic ferns (Salviniaceae). The impressions were assigned to Salvinia cf. minima Baker 1886. These correspond with orbicular to elliptical leaves, with a smooth margin, and both the apex and the base are rounded. The base bears a slightly developed petiole. The venation pattern is dichotomous with anastomoses forming areolas. Generally, four tubercles (trichome bases) per areola are observed. The massulae and spores correspond to Azolla cristata Kaulfuss 1824. The massulae are rounded, oval or kidney-shaped and have septate glochidia. Spores are trilete and spheroidal. The floating ferns Salvinia and Azolla are good indicators of open fresh-water or wetlands paleo-environments. Hence, the lower levels of the Fidelidad Formation are associated with mostly calm freshwater bodies such as rivers, streams or wetlands, which are closely related to the activity of the Bermejo River during the late Holocene. These aquatic fern fossils provide new insights into paleoenvironmental conditions and increase the paleontological richness of the Eastern Chaco.
format Artículo
author Contreras, Silvina Andrea
Robledo, Juan Manuel
author_facet Contreras, Silvina Andrea
Robledo, Juan Manuel
author_sort Contreras, Silvina Andrea
title Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
title_short Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
title_full Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
title_fullStr Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
title_full_unstemmed Aquatic ferns (Salviniaceae) in the Holocene sediments from the Bermejo River, Eastern Chaco, Argentina
title_sort aquatic ferns (salviniaceae) in the holocene sediments from the bermejo river, eastern chaco, argentina
publisher Elsevier
publishDate 2026
url http://repositorio.unne.edu.ar/handle/123456789/60110
work_keys_str_mv AT contrerassilvinaandrea aquaticfernssalviniaceaeintheholocenesedimentsfromthebermejorivereasternchacoargentina
AT robledojuanmanuel aquaticfernssalviniaceaeintheholocenesedimentsfromthebermejorivereasternchacoargentina
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