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Distribution of outcrops of the Ca~ nad on Asfalto Formation in the middle Chubut River valley, Patagonia, Argentina. A: Location of the Ca~ nad on Lahuinc o 'A' section. 

Distribution of outcrops of the Ca~ nad on Asfalto Formation in the middle Chubut River valley, Patagonia, Argentina. A: Location of the Ca~ nad on Lahuinc o 'A' section. 

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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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... studied interval crops out in the Cerro C ondor depocenter situated in the middle valley of the Chubut river ( Figure 1). Assigned palynologically to the Late ToarcianÀLate Bajocian (Olivera 2012), the Ca~ nad on Asfalto Formation rests unconformably on the Lonco Trapial Formation. The Ca~ nad on Asfalto Formation is composed of three informal units. The basal unit comprises limestones, minor conglomerates and sand- stones, plus tuffs and basaltic intercalations reflecting the interdigitation of a lacustrine environment with an active volcanic system. The middle unit consists pre- dominantly of sandstones and siltstone, while the upper unit is not recognized in the studied area (Olivera 2012). The formation is unconformably over- lain by the Cretaceous deposits of the Chubut Group (Cabaleri & Armella ...
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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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... the present material, we recognized the different stages in the development of the fungal spore Annella capitata, beginning as small hyphae (Plate 1, figures 3, 8À10), then spores (Plate 1, figures 1À6, 8À15), then remnant evidence, such as pits and holes on the host (Plate 1, figure 7), as well as the presence of a few spores as record of its biogenic activity. These charac- teristics are distinctive and are not present in grains having sporopollenin ubisch bodies. Identifying the different growing phases and the results of the fungal activity constitute potentially valuable tools in system- atic palynomorph studies. Therefore, the accurate tax- onomic assignment of deteriorated palynomorphs requires the evaluation of the overall association and the degree and type of deterioration, and identifying the activity of the different microorganisms that could hide or obliterate specific characters. This paper is a contribution to understanding the taphonomic effects of fungi on ...
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... the present material, we recognized the different stages in the development of the fungal spore Annella capitata, beginning as small hyphae (Plate 1, figures 3, 8À10), then spores (Plate 1, figures 1À6, 8À15), then remnant evidence, such as pits and holes on the host (Plate 1, figure 7), as well as the presence of a few spores as record of its biogenic activity. These charac- teristics are distinctive and are not present in grains having sporopollenin ubisch bodies. Identifying the different growing phases and the results of the fungal activity constitute potentially valuable tools in system- atic palynomorph studies. Therefore, the accurate tax- onomic assignment of deteriorated palynomorphs requires the evaluation of the overall association and the degree and type of deterioration, and identifying the activity of the different microorganisms that could hide or obliterate specific characters. This paper is a contribution to understanding the taphonomic effects of fungi on ...
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... ubisch bodies The Ca~ nad on Asfalto palynoflora is characterized by an abundance of gymnosperm pollen grains. Among these, the coniferous genera are particularly promi- nent, mainly those belonging to the Cheirolepidiaceae and Araucariaceae families. Cheirolepidiaceae (Classo- pollis) reach up to 93% of the total assemblage of paly- nomorphs. Specimens with different degrees of preservation have been found, ranging from very well preserved to lacking most of their original morphologi- cal features. A significant proportion of the studied palynomorphs that yield fungal spores assigned to Annella capitata Srivastava (Plate 1, figures 1À6) are Table 2. Botanical affinities of spores, pollen and organic-walled microplankton from the Ca~ nad on Asfalto Formation. Affini- ties of the dispersed palynomorphs are based on Dettmann (1963), Filatoff (1975), de Jersey & Raine (1990), Balme (1995), Sajjadi & Playford (2002a, 2002b, McKellar (1998) identified as Classopollis sp., and the result of fungal activity on these grains is marked (Plate 1, figure 7). Different phases in the development of this fungus were recognized. The development of fungal spores from the hyphal bodies begins with the spores initially forming in isolation but eventually in rows, and finally producing dense agglomerations of spherules (Plate 1, figures 2, 8À10). It has also been possible to observe the fossil germination of some spores (Plate 1, figures 10À11). Hyphae, which are present only in the early stages of spore development, as described by Srivastava (1976), were recognized in a few pollen grain hosts (Plate 1, figures 5, 8À9). According to Srivastava (1976), when the spores reach a mature stage, the hyphae disintegrate. In a final phase of development, the spores detach from the palynomorphs, revealing their exines. The resulting pattern of exine degradation consists of a series of pits and perforations (Plate 1, figure 7). Because of the large number of Classopollis sp. grains studied, the different stages of deterioration were discernable. A. capitata initially infects the outer layer of the exine (the sexine), modifying some mor- phological features of the grain surfaces until only relicts of the morphostructure remain to permit identi- fication of the taxon (e.g., endostriae). In the advanced stage of bio-corrosion (microbiological activity sensu Delcourt & Delcourt 1980), the sexine becomes fully detached from the inner wall, and generally broken, making it possible to observe the internal wall or nex- ine (Plate 1, figures 12À13). These remnant nexines can often be identified without their outer wall, whether clearly colonised by the fungi or not (Plate 1, figure 14). The damage caused by A. capitata could lead to a misclassification of the host specimens, even at the family level. For example, Inaperturopollenites sp. A and Spheripollenites sp. in Volkheimer (1972) show general characteristics (e.g., dimensions, wall thickness, shapes) which agree with the morphological features of the nexines of Classopollis grains found in this work. Therefore, they might have been mistakenly included in the Araucariaceae and/or Cupressaceae families. Kalgutkar & Jansonius (2000, p. 26) mentioned 'that Jansonius & Hills (1977 interpreted the spherules as glomerules or ubisch bodies'. Ubisch bodies are circular structures produced during the final stages of the formation of pollen grains through an excess sporopollenin in the tapetal structure. These are generally minute, variously ornamented bodies, usually with a central cavity. These 'orbicules' show the same chemical and optical characteristics as pollen exine (Traverse 1991). Gamerro (1968) described tapetal membranes and ubisch bodies found in male cones of Apterocladus lanceolatus Archangelsky (pollen grain: Callialasporites), Brachyphyllum irregular Archangel- sky (Inaperturopollenites), Tomaxelia biforme Archan- gelsky (Classopollis) and Trisocladus tigrensis Archangelsky (Trisaccites). Ubisch bodies identified in Callialasporites Sukh Dev emend. Maheshwari show a subcircular to round elongate shape (1 to 3 mm wide), and few of them present a central cavity. Orbicular spheres adhered to Inaperturopollenites Pflug & Thom- son present diverse shapes and sizes (1.5 to 6 mm or more in diameter) and show an irregular distribution on the grain surface. Some of them present a central cavity. Similarly, ubisch orbicules adhered to Classo- pollis Pflug grains have a homogeneous shape and size (1.3 to 1.5 mm in diameter) and are regularly distrib- uted on the surface of the grain. They are subhexago- nal in outline and have a defined central cavity. Ubisch bodies identified in Trisaccites Cookson & Pike show a subhexagonal shape and a clear central cavity, their overall size being smaller than those of the previously mentioned species (up to 1.5 mm). More recently, Lovi- solo & Galati (2012) described 10 species of Poaceae and recognized four different types and four subtypes of orbicules or ubisch bodies. They concluded that the different ubisch body-types were representative of the studied tribes and suggested that orbicule morphology may be a useful character in systematic studies. Srivastava (1976) compared the fungal spores with the ubisch bodies and claimed that the structure, fos- silization and adherence type of the former differ sig- nificantly from those of the latter. Ubisch bodies are attached superficially to the pollen surface and readily fall off during pollen grain dispersal and/or by physi- cal-chemical laboratory treatments; they are thus found only rarely in the fossil record (Srivastava ...
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... grains with fungal spores and hyphae of A. capitata were recorded in the Ca~ nad on Lahuinc o 'A' section (S43 30 0 59 00 , W69 8 0 20 00 ), located 15 km south of Cerro C ondor village (Figures 1 and ...

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