Figure 1.
Map showing the location of the outcrops of the La Colonia Formation examined for this study in the Cerro Buitre and Arroyo Mirasol Chico areas.
Modified after (101).
Figure 2.
Stratigraphic sections of the La Colonia Formation at the Cerro Bosta locality (a) and Cañadón del Irupé/Quebrada del Helecho localities (b).
Note distribution of lagoon facies and fresh water horizon after correlation of aquatic plants.
Figure 3.
Free-floating microphyte components (chloroccocalean microalgae).
A, B (SEM): Pediastrum spp.; BAFCB meb 262. C: Botryoccocus sp. (SEM); BAFCB meb 262. D, E: Zygnemataceae spores (LM); BAFCB pm 260. Scales A, B, C = 1000 µm; D, E = 10 µm.
Table 1.
Distribution and abundances of plant taxa represented by micro- and macrofossils at the three localities studied.
Figure 4.
Spores and pollen organs representing free-floating aquatic macrophytes.
A: Azolla-like megaspore (SEM) without floats preserved; MPEF-MEB 5505 (scale = 50 µm). B: Azolla microspore massula (SEM); BAFCB meb 263 (scale = 20 µm). C: Paleoazolla patagonica megaspore with floats preserved (SEM); MPEF-MEB 5506 (scale = 200 µm). D: Paleoazolla patagonica microspore massula (SEM); MPEF-MEB 5507 (scale = 10 µm). E: Araceae pollen grain (Pandaniidites sp.); BAFCB pm 259 (LM) (scale = 10 µm).
Figure 5.
Free-floating aquatic macrophyte components from the Cañadón del Irupé locality.
A, C: Lemnoid leaves; MPEF-Pb 3983. B, D: Azolla sporophytes B. Sporophyte with sporocarps (s, arrows); MPEF-Pb 5060. D: Sterile sporophytes; MPEF-Pb 5081. Scales A, C = 1 cm; B, D = 5 mm.
Figure 6.
Rooted/rhizomatous macrophytes.
A: Regnellidium thomas-taylorii rhizomes, rootlets, petioles and leaflets; MPEF-Pb 5405. B: R. thomas-taylorii leaflets; MPEF-Pb 5446. C: Mirasolita leaflets; MPEF-Pb 5521. D: Luigimarsiglia sporocarps; MPEF-Pb 5527. E: Nelumbo puertai leaf; MPEF-Pb 864. F: Nelumbo-like associated reproductive organ; MPEF-Pb 920. Scales = 1 cm.
Figure 7.
Rooted/rhizomatous macrophytes represent by spores and pollen.
A: Molaspora lobata megaspore (SEM) associated with Regnellidium thomas-taylorii; MPEF-MEB 5501 (scale = 50 µm). B: Crybelosporites microspore (SEM) associated with Regnellidium thomas-taylorii; MPEF-MEB 5502 (scale = 10 µm). D: Molaspora lobata megaspore (SEM) associated with Mirasolita and Luigimarsiglia; MPEF-MEB 5503 (scale = 50 µm). D: Nelumbo-like tetracolpate-reticulate pollen grain (SEM); BAFCB pm 263 (scale = 10 µm).
Figure 8.
Reconstruction of the plant communities at the Cerro Bosta locality.
Surrounding (close-allochthonous) terrestrial vegetation: (a) Arecaceae, (A) Euterpe (Plantsystematics.org- DOL11633) and (b) Dicksoniaceae, (B) Dicksonia sellowiana (Photo by R. Moran, Plantsystematics.org- DOL75000). Autochthonous vegetation: Emergent-rooted macrophyte (c) Regnellidium thomas-taylorii, (C) Regnellidium diphyllum (Photo by D.W. Stevenson, Plantsystematics.org- DOL25635) and free-floating macrophyte (d) Azolla and Paleoazolla, (D) Azolla (Photo by R. Moran, Plantsystematics.org- DOL6803).
Figure 9.
Reconstruction of the plant communities at Cañadón del Irupé/Quebrada del Helecho localities.
Surrounding (close-allochthonous) terrestrial vegetation: (a) Arecaceae, (A) Euterpe (Plantsystematics.org- DOL11633), (b) Dicksoniaceae, (B) Dicksonia sellowiana (Photo by R. Moran, Plantsystematics.org-DOL75000), and (c) Typha-like, (C) Typha latifolia (Photo by K.C. Nixon, Plantsystematics.org- DOL6212). Autochthonous vegetation: Emergent-rooted macrophytes: (d) Mirasolita-Lugiomarsiglia, (D) Marsilea scalaripes (Photo by D. Nickrent, PhytoImages.siu.edu-DOL69348) and (e) Nelumbo puertae and reproductive structures, (E) Nelumbo lutea (Photo by R. Moran, Plantsystematics.org- DOL42110); and freeifloating macrophytes: (f) Araceae, (F) Pistia lactucoides (Photo by K.C. Nixon, Plantsystematics.org- DOL4884) and (g) Azolla and Paleoazolla, (G) Azolla (Photo by R. Moran, Plantsystematics.org- DOL6803).
Figure 10.
Main representatives of the surrounding lowland vegetation.
A: Dicksoniaceous fertile and sterile fronds; MPEF-Pb 6457. C: Dicksoneaceous spore massulae; BAFCB meb 263. B: Typhaceous leaf; MPEF-Pb 5074. D: Arecipites type pollen grain; BAFCB meb 261. E: Podocarpaceous bisaccate pollen grain; BAFCB meb 262. F: Classopolis pollen grain; BAFCB meb 259. G: Typhaceous pollen grain; BAFCB meb 260. C, D, E (SEM); F, G (LM). Scales: A, B = 1 cm; C = 20 µm; D = 5 µm; E, F, G = 10 µm.