Polens e esporos associados a megafosseis vegetais em S.J. do Triunfo, PR, formação rio bonito (permiano)

M Arai, O Rosler

Resumo


The study of pollen and spores of a carbonatic siltstone at the base of the fossil-plant-bearing strata of the São João do Triunfo locality (Rio Bonito Formation, Tubarão Group, Paraná Basin in the south of the State of Paraná, Brazil) is here presented. It is part of a project that also includes similar studies of other localites, with the objective to improve biostratigraphic and paleoenvironmental interpretations. In fact, it contributes with additional information on the Permian paleofloral composition through the study of the relationships between "micro-" and "megaflora". In the present study, the main identified miospores belong to the following genera: Portalites. Vittatina, Protohaploxypinus, Striomonosaccites, Florinites, Apiculatisporites, Raistrickia, Leiotriletes, Calamospora and Punctatisporites. Monoporiti is predominant (45%). The percentage of trilete spores is 37%, but only 10% of them are ornamented. Monolete spores com prise 8% and both monosaccites and striatites make up 5% each. Regarding the age, this qualitative and quantitative composition would suggest a correspondence with the Early to Middle Artinskian, about the same as previously suggested by the plant megafossils alone. The low percentage of striatites is consistent with the low percentage of (and with the kind of glossopterids in the same horizons. Punctatisporites is probably related to some of the ferns, which are very abundant among the megafossils; Calamospora is probably related with the sphenopsids (Phylloteca and Annularia, occur together with Paracalamites). Lagenoisporites is a very common megaspore almost certainly related to Brasilodendron, the characteristic lycopsid of this phytozone.

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