Cretaceous cicatricose spores from north central-western Argentina: taxonomic and biostratigraphic discussion

Abstract

Cicatricose spores have been described from Cretaceous basins worldwide. A complete revision of previous records from Argentina and other parts of South America is presented here, as well as the results of a detailed taxonomic study of the species found in the La Yesera and Lagarcito formations (north and central-western Argentina, respectively). Four genera and 11 species are described: Cicatricosisporites cuneiformis, C. pramparoana, C. sp. 1, Fisciniasporites sp. cf. F. brevilaesuratus, F. sp., Nodosisporites sp., Ruffordiaspora australiensis, R. cardielensis, R. ludbrookiae, R. cf. R. ticoensis and R. sp. 1. The genus Fisciniasporites is recorded for the first time in Argentina (in the La Yesera Formation), and similarly Nodosisporites in the San Luis Basin. The abundance of cicatricose spores is higher in the La Yesera Formation (8?54.2% of the total assemblage) than in the Lagarcito Formation (2?16%). An acme of cicatricose spore diversity in Argentina was recognized during the Aptian?Albian interval. Taxonomic studies of these types of spores are very important as they constitute a useful example of accurate descriptions and illustrations within a morphological group that has many misidentifications, and also considering the biostratigraphical significance of some species, e.g. Cicatricosisporites cuneiformis in Australia