The Lopingian palynological Guttulapollenites hannonicus–Cladaitina veteadensis assemblage zone of Argentina, stratigraphical implications for Gondwana

The Lopingian Series, especially the Changhsingian Stage are here recognized for the first time in South America, in conjunction with the proposition of a new biostratigraphic unit for the uppermost Permian. The palynoflora recovered from the type section of the La Veteada Formation, La Rioja Province, Paganzo Basin, Argentina, allows the definition of the Guttulapollenites hannonicus–Cladaitina veteadensis (HV) Assemblage Zone. It is characterized by the appearance of Guttulapollenites hannonicus, Cladaitina veteadensis, Secarisporites imperialis, Densoisporites complicatus and Syndesmorion stellatum, together with Reduviasporonites chalastus, Klausipollenites spp., Minutosaccus acutus, Scheuringipollenites ovatus, Triadispora crassa, Vitreisporites pallidus, V. microsaccus, Corisaccites alutas, Staurosaccites cordubensis, scarse Vittatina simplex and Weylandites spp.; its descreteness is supported by various statistical analyses. The new HV Zone contains the co-occurrence of species characteristic both of the Permian (Syndesmorion stellatum, Jugasporites spp., Striomonosaccites circularis, S. triangularis, Lueckisporites angoulensis, L. crassus, L. balmei, Lunatisporites variesectus, L. globus, Protohaploxypinus suchonensis, Striatopocarpites phaleratus) and the Triassic (Densoisporites spp., Lundbladispora brevicula, L. obsoleta, L. springsurensis, L. wilmotti, Ringosporites fossulatus, Goubinispora morondavensis, Minutosaccus potoniei, M. schizeatus). Therefore, it likely represents a flora developed close to the extinction of end Permian event. The HV Zone is herein referring to the latest Lopingian (Changhsingian stage) without discard that it could probably extends to lowermost Triassic in age.