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The fungal spore Annella capitata Srivastava is recorded for the first time in Argentina, within the continental Jurassic strata of the Cañadón Asfalto Formation, Cañadón Asfalto Basin, Patagonia. It is identified on pollen grains belonging to the Cheirolepideaceae, Araucariaceae and Podocarpaceae. This paper contrasts A. capitata with ubisch bodie...
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... total of 57 outcrop samples of very fine sandstone, silt- stone and mudstone were collected from the Ca~ nad on Lahuinc o 'A' section ( Figure 2). Twenty palynologically productive samples (those yielding at least 300 palyno- morph counts per sample) were studied ( Table 1). The physical and chemical extraction of palynomorphs was carried out at the Palynological Laboratory of the Insti- tuto Geol ogico del Sur/Universidad Nacional del Sur- Bah ıa Blanca and at the Paleopalynological Laboratory of the Instituto Argentino de Nivolog ıa, Glaciolog ıa y Ciencias Ambientales/Centro Cient ıfico Tecnol ogico- Consejo Nacional de Investigaciones Cient ıficas y T ecnicas-Mendoza, Argentina. Processing of samples involved hydrochloric acid (HCl)/hydrofluoric acid (HF) treatment and subsequent sieving (through a 10 mm mesh), followed by 2 minutes of oxidation with concen- trated nitric acid (HNO 3 ). This residue was briefly washed (45 seconds) in 5% ammonium hydroxide to remove the oxidation by-products. The slides were exam- ined using transmitted light and differential interference contrast (DIC) microscopes (both an Olympus BX40 and a Nikon Eclipse 80i). Photomicrographs of selected palynomorphs were taken using either an Olympus or a Nikon digital camera. In addition, a Philips XL30 TMP New Look scanning electron microscope was used to study two samples (MPEF-PALIN122 and MPEF- PALIN123), which were selected because they contained high percentages of A. capitata Srivastava spores. The palynological slides are housed in the Paleontological Museum Edigio Feruglio Repository, Trelew city, Chu- but province, Argentina. They are indentified by the cat- alogue number preceded by the abbreviations MPEF (Museo Paleontol ogico Edigio Feruglio) and PALIN (Palynology). Specimen locations are referred to Eng- land Finder coordinates (EFco). Table 2 shows that the studied samples contain a low- density and low-diversity assemblage of spores (four species) but abundant and diverse pollen grains (38 species), accompanied by organic walled microplank- ton comprising four species of the Zygnemataceae and Botryococcaceae families, and acritarchs (Leiosphaeri- dia spp.). The relative abundances of the major palyno- morph groups are expressed in percentages in Figure 3. Nearly 90% of the sporomorphs identified in the Ca~ nad on Lahuinc o 'A' section ( Figure 1) are gymno- sperm pollen grains, and many of these were appar- ently infected by the fungus that formed A. capitata spores. It is notable that none of the scarce spores of lycophytes and ferns within the palynoflora exhibit this infection. Description. Aseptate and inaperturate spores. Amb circular to subcircular with psilate exine. Small hyphae produce spores and then disintegrate when the spores are ...
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... palynological assemblages recognized in the different horizons show a high proportion of Cheirole- pidiaceae and Araucariaceae, and the presence of upland forest components (mainly Podocarpaceae and Pinaceae) indicates that warm-temperate and relatively humid conditions prevailed in the region surrounding the depocentre (Olivera 2012). The other components of the palynoflora (bryophyte, lycophytes and filicop- sida spores, and pollen grains of Corystospermaceae and Caytoniaceae families) (Figure 3) suggest a sea- sonal, sub-tropical palaeoclimate for the Ca~ nad on Asfalto region during late Early to mid Middle Jurassic time (Olivera ...
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Citations
... 28e), indicating the presence of open water. In deep-time records, Annella capitata and A. pulchra with aspects of chytrids that parasitize pollen grains were documented in Jurassic strata (Srivastava 1976;Marcinkiewicz 1979;Srivastava 2011;Olivera et al. 2015). It has also been suggested the hyphae of Ericoid mycorrhiza parasitize pollen in nutrient-limited environments (Shumilovskikh et al. 2015b;Fig. ...
Non-pollen palynomorphs (NPPs) are ‘extra’ microfossils often found in palynology slides. These include remains of organisms within the size range of pollen grains (∼10-250 microns), resistant to laboratory treatments used for the preparation of palynological samples. NPPs are a large and taxonomically heterogeneous group of remains of organisms living in diverse environments. Taxonomically, they belong to a wide variety of groups such as cyanobacteria, algae, vascular plants, invertebrates, and fungi. The aim of this chapter is to provide a general overview of NPP groups observed in palynology slides. It includes more than 40 of the most common groups starting with acritarcha, cyanobacteria and algae, moving through transitional groups to animals and fungi and finishing with human-made objects such as textile fibres. Although far from complete, it provides an updated overview of taxonomical diversity of NPPs and their indicator values. Further works on NPP identifications are of great importance to improve of our current knowledge. Since NPPs occur in all kinds of sediments, their analysis is a powerful tool for reconstructing environmental changes over time. Further detailed studies of specific NPP groups and their indicator values will open the way for new fields of study.
... Records of fungal structures in palynological slides derived from Gondwanan deposits are not scarce, mainly concerning to spores, but hyphae remains are very rare (see di Pasquo, 1999;Olivera et al., 2015), demonstrating difficulties in preservation and/or inability in the identification of these structures. Furthermore, the Gondwanan records of fungal reproductive structures are mostly found within dispersed organic matter retrieved from palynological slides. ...
Portalites is a Gondwanan organic-walled microfossil, especially found in Carboniferous and Lower Permian coal beds and associated strata. The genus is represented by three species: P. confertus (type species), P. gondwanensis and P. baculus, described from Saudi Arabia, Brazil and Argentina, respectively. In this paper we present a detailed morphological analysis of the main features of this genus, including (i) spore diameter, (ii) wall structure and thickness, (iii) ornamentation pattern, and (iv) presence, quantity and size of pores (functional and non-functional ones). The material comprises well preserved specimens, analysed with optical microscopy and scanning electron microscopy, derived from the Paraná (Rio Bonito Formation) and the Amazonas (Monte Alegre and Itaituba formations) basins, Brazil, ranging from the Pennsylvanian to the Cisuralian. Although we have observed a very close resemblance with coeval genera Arabisphaera and Spongocystia, the presence of a main pore, from which a channel is developed beyond the spore wall, distinguishes Portalites from these taxa. Species of Portalites exhibit a clear variation in some morphological features, mainly in ornamentation pattern and, secondly, in overall diameter and wall thickness. A new diagnosis is given for Portalites, as well as amendments in the diagnosis of P. gondwanensis. We present the first reports of P. confertus and P. baculus in Brazil, as well as spores with presumed fungal morphological structures, confirming its biological affinity.
... The former consists of lacustrine sediments with volcanic intercalations at the base, while the latter is mainly siliciclastic and represents a prograding fluvial system on the previous lacustrine deposits. In this study, we do not recognise such a subdivision for the Cañad on Asfalto Formation (Olivera 2012;Olivera et al. 2014). This formation is unconformably overlain by fluvial to lacustrine deposits of the Cañad on Calc areo Formation. ...
The Cañadón Asfalto Formation, Cañadón Asfalto Basin, Patagonia, Argentina, is interpreted as fluvial-lacustrine deposits. A palynological study of the lower and middle parts of the unit, at the Cañadón Lahuincó and Cañadón Caracoles sections, Cerro Cóndor Depocentre Chubut province, northwestern Patagonia, Argentina is presented. The quantitative composition of the palynofloras is characterised by the dominance of pollen produced by the conifer families Cheirolepidiaceae (Classopollis) and Araucariaceae (mainly Araucariacites and Callialasporites), suggesting that warm-temperate and relatively humid conditions under highly seasonal climate prevailed during the depositional times of the unit. The abundance of Botryococcus supports the presence of a shallow lake with probably saline conditions. Five palynomorph ecogroups (PEGs) were recognised: upland, lowland, riverside, coastal lake and aquatic. The ecological requirements of the different plant families forming the PEGs enable the inference of a sub-tropical palaeoclimate for the Cañadón Asfalto region during late Early Jurassic to mid Middle Jurassic, which is consistent with the ‘seasonally dry (winterwet)’ biome.
The El Foyel Group is defined in the western section (Andean) of the Ñirihuau Basin, Argentina (41°44′S-71°30′W). It consists of three units: the Troncoso, Salto del Macho and Río Foyel formations. The age of the group and of the formations is still controversial. We studied the fungal remains recovered from 14 palynological samples from outcrops in the group with the intention of providing data to solve this problem. The fungal assemblage found is highly diverse and it is mostly composed of spores of different affinities (mainly ascomycetes). We identified 38 species from 18 genera (Anatolinites, Dictyosporites, Didymoporisporonites, Diporicellaesporites, Diporisporites, Dyadosporites, Exesisporites, Foveodiporites, Hypoxylonites, Inapertisporites, Lacrimasporonites, Monoporisporites, Multicellites, Papulosporonites, Pluricellaesporites, Polycellaesporonites, Staphlosporonites and one indet.). Moreover, we propose two new species (Hypoxylonites foyelensis sp. nov. and Pluricellaesporites patagonicus sp. nov.) and a new combination (Dyadosporites annulatus comb. nov.). Most of the species were recovered from samples from the Troncoso Formation (21), while the Salto del Macho and Río Foyel formations showed lesser diversity. Anatolinites subcapsilaris, Dyadosporites subovalis, Inapertisporites subovoideus, Monoporisporites singularovalis and Multicellites ellipticus, biomarkers from the Middle Eocene appeared in the Troncoso and Salto del Salto del Macho formations; whereas indicators of the Eocene-Oligocene, such as Dyadosporites elsikii, Didymoporisporonites panshanensis, Foveodiporites elegans, Lacrimasporonites fusoides and Multicellites leptaleus, were mainly recorded in the Río Foyel Formation. The appearance of the biomarkers mentioned above reinforces the Palaeogene age proposed for the El Foyel Group in previous palynological studies. The record of Hypoxylonites ater (Miocene) in the Salto del Macho formation would expand its range as far back as the Palaeogene.
