Late Cretaceous aquatic plant world in Patagonia, Argentina

• Main Authors: Cúneo, N.R., Gandolfo, M.A., Zamaloa, M.C., Hermsen, E.
• Format: Journal/Newspaper
• Language: unknown
• Subjects: aquatic flora; Araceae; Argentina; article; Atlantic Ocean; azolla; Botryoccocus; coastal plain; conifer; controlled study; Dicksoniaceae; fern; fossil plant; geographic origin; green alga; lagoon; macrophyte; Nelumbo; nonhuman; Paleoazolla; paleoecology; Pediastrum; plant community; plant structures; plant taxonomy; Regnellidium; sedimentation; species dominance; terrestrial species; Typhaceae; Upper Cretaceous; vegetation dynamics; Zygnemataceae; angiosperm; aquatic species; classification; ecosystem; geography; plant; population dynamics; ultrastructure; Angiosperms; Aquatic Organisms; Plants; South Atlantic Ocean
• Online Access: https://hdl.handle.net/20.500.12110/paper_19326203_v9_n8_p_Cuneo

In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla ) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America. © 2014 Cúneo et al. Fil:Cúneo, N.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Gandolfo, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Zamaloa, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.