Tempo and mode in the replacement of trilobite evolutionary faunas from the Cordillera Oriental basin (Northwestern Argentina)

摘要: Abstract Major ecological transitions among evolutionary faunas are matters of continual debate. Our study analyses the timing and mode replacement Ibex I II Trilobite Evolutionary Faunas (TEF) in Lower Ordovician successions northwestern Argentina, with special emphasis on olenids asaphids as key groups faunas, respectively. We explore richness by using sample rarefaction method, occupancy based a presence–absence dataset. The late Tremadocian 2 (Tr2) represents an inflexion point trajectories olenids. While diminish their generic through time, became richest family since Tr3 predating global trend recognized for expansion Fauna. Asaphids gained diversity at expense other trilobites well, rise lags behind increase suggesting displacement scenario probable between TEFs. Apparently, processes variate regions across globe, configuring complex mosaic regional patterns.