Occurrence of Cyclusphaera scabrata in Achiri (late middle-early late Miocene?, Bolivian Altiplano): Paleogeographical implication

• Published in: Journal of South American earth sciences 2022-11, Vol.119, p.103990, Article 103990
• Main Authors: Prámparo, Mercedes B., Antoine, Pierre-Olivier, Marivaux, Laurent, Andrade Flores, Rubén, Fernández-Monescillo, Marcos, Boscaini, Alberto, Mamani Quispe, Bernardino, Fauquette, Séverine, Bonnet, Colline, Münch, Philippe, Pujos, François
• Format: Article
• Language: English
• Subjects: Araucarian dispersed pollen; Biodiversity and Ecology; Botanics; Earth Sciences; Environmental Sciences; Life Sciences; Mauri Formation; Neogene palynomorphs; Northwestern altiplano; Paleontology; Sciences of the Universe; Vegetal Biology
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2022.103990

A palynological assemblage including the extinct araucarian dispersed pollen, Cyclusphaerascabrata, was analysed from the Achiri locality, Bolivian Altiplano. The fossil-yielding locality of Achiri is located in the Pacajes Province, La Paz Department, in the northwestern Altiplano, Bolivia. The Achiri locality is very well known by the fossil vertebrate faunas recovered from the Mauri Formation (M6). The palynological samples come from fine-grained and plant-rich lacustrine levels lower in the same unit. An age between late middle to early late Miocene? was inferred for the palynological association studied, based on local stratigraphy and radioisotopic ages obtained higher in the series. The retrieved association is mainly represented by angiosperms; although gymnosperms, bryophytes, ferns, and fresh-water algae are also documented. Compositae are the most abundant group within angiosperms, and Polylepis also occurred but in low percentages. The presence of C. scabrata in the Bolivian Altiplano expands the taxon distribution outside northern South America and provides additional evidence to infer timing and distribution routes of conifers, restricted toward the tropics during the latest Neogene. Its occurrence supports a paleoelevation of no more than 2000 m for the northern area of the Altiplano in agreement with previous results. Compositae of Fenestrites type and Polylepis occur earlier in Bolivia and C. scabrata later, comparing their occurrence in miocene microfloras from low to mid-latitudes of South America. •Occurrence of Cyclusphaera scabrata in the Miocene Bolivian Altiplano.•Confirmed southernmost distribution of C. scabrata during the Neogene.•The Achiri locality is very well known by the fossil vertebrate faunas.•Compositae are the most abundant group within angiosperms including fenestrate types.•Incipient presence of Polylepis are indicative of the sub-puna shrubland vegetation.