New data on the Silurian-Devonian palaeontology and biostratigraphy of Bolivia

Abstract

In order to precisely establish the bio- and chronostratigraphic position of several levels of the Silurian-Devonian succession of Bolivia, with respect to the International Time Scale, additional Silurian and Devonian localities belonging to the Eastern Cordillera and the Interandean Zone areas have been recently revised and sampled, both for macrofossils and palynomorphs. Specifically, the localities are Ñuñumayani, and Muruhuta from the late Silurian-early Devonian time interval. Correlations with other fossiliferous localities are discussed, namely Huacallani and Rumicorral. A new outcrop yielding Middle Devonian tabulate corals at Pisacaviña is described; its faunal content is described, and compared with the historical coral collection. As a result, it appears clearly that the Silurian-Devonian Bolivian fauna needs a thorough revision, as well as the selection of stratigraphically significant macrofossils. Besides macrofossils, the analysis of palynomorph assemblages is significant in establishment of both intra-Bolivian and international correlations before any reliable biogeographic reconstruction is done. This paper records the first discovery of a plant of the genus Protolepidodendron from the Devonian of Bolivia. An ostracod assemblage from Pisacaviña is described, illustrated, and discussed for the first time; it suggests an Early Devonian or an Eifelian age. Newly described taxa include the coral Parastriatopora boliviana sp. nov., and the chonetoidean brachiopods Sanjuanetes glemareci sp. nov., and Kentronetes giae sp. nov.