Ups and downs of belemnite diversity in the Early Jurassic of Western Tethys
Journal: Palaeontology
Year: 2021

Abstract Although belemnites form a major clade of extinct cephalopods, the early stage of their diversification remains poorly known in time and space. Here we investigate the first diversification episodes of belemnites (order Belemnitida) using a new species‐level database encompassing the Hettangian–Aalenian interval (Early Jurassic – earliest Middle Jurassic) and covering the Western Tethys. Rarefied richness shows a four‐fold increase from the Planorbis chronozone to the Ibex chronozone, a