Figure 1.
Comparison of extinction versus origination/speciation across the Middle to Late Devonian interval. Late Devonian Biodiversity Crisis interval is indicated in yellow. (A) Proportion of generic extinction or origination per interval. Modified from Bambach et al. (2004). (B) Instantaneous rates of species extinction and speciation for two brachiopod genera (Schizophoria and Floweria), one bivalve genus (Leiopteria), and all three clades combined. Modified from Stigall (2010a). Similar patterns occur at both taxonomic levels: Origination/speciation rates are substantially reduced during the crisis interval, but extinction rates are lower than during the Middle Devonian background interval.