The mid-Famennian ammonoid succession in the Rhenish Mountains: the "annulata Event" reconsidered

Abstract

The mid-Late Devonian pelagic sedimentary successions of the Rhenish Mountains and other regions show a double black shale horizon called the annulata Black Shale. It marks, at the species level, a prominent faunal turnover of ammonoids from the Prolobites delphinus Zone into the Platyclymenia annulata Zone. An analysis of ammonoid genera distribution, phylogenetic relationships, and morphospace occupation demonstrates that the "annulata Event" does not correspond to a crisis of the group and does not fulfill the criteria of a major biotic event.