Fig. 2

A Regional belemnite species richness rarefied to 20 specimens where possible. Boxes refer to the relative availability of localities with a suitable sample size; B belemnite raw species richness (updated curve) compared to the corresponding estimators Chao 2 (light grey line) and ICE (grey dotted line); confidence intervals for raw richness are derived from the unconditional variance computed for sample‐based rarefaction; for the Chao 2 estimator, only the lower bound of the 95% confidence interval is shown for clarity; C Belemnite species richness rarefied or extrapolated to 16 localities and associated 95% confidence intervals; data are plotted at the mid‐points of the time scale of Gradstein et al. (2012). The lower part of the figure shows the chronostratigraphic framework used here (Ja, Jamesoni; Ib, Ibex; Da, Davoei; Ma, Margaritatus; Sp, Spinatum; Te, Tenuicostatum; Se, Serpentinum; Bi, Bifrons; Va, Variabilis; Th, Thouarsense; Di, Dispansum; Ps, Pseudoradiosa; Aa, Aalensis). Red arrows and dotted vertical red lines indicate the two pulses of the second‐order Toarcian crisis