Devonian palynomorphs from the los monos formation, Tarija Basin, Argentina

A diverse and relatively well-preserved palynological assemblage has been recovered from the Los Monos Formation in the Quebrada Galarza well, northwestern Argentina. Ninety-eight species of palynomorphs are represented. Thirty-four are miospores (with two dubiously placed), fifty-one are acritarchs, eight are chitinozoans and five are scolecodonts. Two new genera of acritarchs, Crucidia and Hemiruptia, are proposed herein. Seven new species are described: one spore, Acinosporites ledundae; four acritarchs, Ammonidium garrasinoi, Cymatiosphaera apiaria, Hemiruptia legaultii and Polygonium barredae; and two chitinozoans, Angochitina galarzae and Belonechitina holfeltzii. Previously described species of palynomorphs suggest a late Givetian-early Frasnian age for the Los Monos Formation in the Quebrada Galarza well. Stratigraphic and phytogeographic implications of the palynological assemblage are discussed. The presence of several terrestrial species previously recognized in northern Gondwana and in the Northern Hemisphere reinforces currently accepted paleogeographical reconstructions of the upper Middle through lower Upper Devonian. Acritarch data corroborate the existence of important phytoplanktonic links between Gondwana and the Northern Hemisphere via a relatively temperate marine realm.