In the case of vertebrate taxa at the end of the P-T in the Karoo Basin of South Africa, subsequent additional and intensive sampling effort revealed that the stair-stepped pattern was largely removed with the ends of ranges extending much closer to the boundary (Smith and Ward 2001). Given the much coarser-grained and comparatively poorer insect fossil record during the Late Permian, however, it is possible that the P-T extinction actually occurred during the mid- to Late Permian rather than at the last stage of the Permian, encompassing the three time intervals preceding the event (Fig. 4b). An alternative explanation is that sample size is insufficient to demonstrate the Signor–Lipps effect, even though the pattern (Fig. 4b) is consistent with it. Both explanations are consistent with the total diversity data in Fig. 3 and in the turnover of other terrestrial taxa (Retallack 1995). After the “mother of all extinctions,” there is indication of a distinct Middle Triassic rebound as the early phase of the modern insect fauna was established. It is not until the Late Jurassic (Kimmeridgian Stage) that there is evidence for a third major extinction event (Fig. 4b, arrow 3), coinciding with the origin of many new taxa, discussed earlier. The taxa that became extinct undoubtedly represent less competitive, earlier Mesozoic