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The widespread demise of the Urgonian rudistid-platform ecosystem in the Mediterranean Tethys was so far considered as a progressive phenomenon starting at the Barremian–Aptian transition and culminating in the mid-early Aptian in concert with the Oceanic Anoxic Event (OAE) 1a. The re-assignment of the final demise of the Urgonian-type peri-Vocontian rudistid platforms to the latest Barremian by means of ammonite biostratigraphy forces us to rethink the chronology of events and underlying causes. Re-examination of the best-documented platforms of the Mediterranean Tethys supports a large scale demise of the Urgonian rudist-dominated platforms in the latest Barremian, as demonstrated directly by ammonite occurrences and indirectly by correlations. In most cases, the last rudistid sequences, dominated by caprinid rudists of peri-Vocontian affinity, are topped by an exposure surface. Regional …