The Paradoxides puzzle resolved: the appearance of the oldest paradoxidines and its bearing on the Cambrian Series 3 lower boundary

摘要: The Moroccan Atlas ranges provide sections that help reconstruct the earliest evolution of Paradoxides s.l. A fine-scale analysis basal part Jbel Wawrmast Formation in eastern Anti-Atlas and comparisons with other southern Morocco not only shows abrupt appearance Acadoparadoxides nearly monofacial successions, but also illustrates a rapid diversification genus. This remarkable clade includes material can be assigned provisionally to frequently described species mureroensis (Sdzuy, 1958), A. nobilis (Geyer, 1998) new pampalius, levisettii ovatopyge, which pampalius shown oldest presently known. biostratigraphic depositional development permits precise evaluation suggested correlations within West Gondwana into Cambrian continents, attempts at based on species, particularly as key taxon for global correlation, suffer from deficiencies become obvious. In addition, often subtle differences between illustrate confident identification these is possible well-preserved largely undistorted specimens. Thus, many reports may based, part, unfavourably preserved specimens species. concept fairly variable even idea dimorphism seem have led problematic identifications. this context, Taurus Mountains, Turkey, identified herein deani n. sp. appear been quite provincial their palaeogeographic distribution, an early appearing harlani (Green, 1834) was restricted Avalonia palaeocontinent, incorrectly reported cannot used basis lower Series 3 correlation or chronostratigraphy. Finally, so-called Valdemiedes Event Iberian Chains Spain obviously regional feature early, earliest, trilobite assemblage above barren interval. “event” appears local stratigraphic artefact does reflect Gondwanan geological history.