If extinctions are random in their effect, then replaying them will yield very different results. In this case, the dice (actually it was a random number generator) spelled oblivion for the crocodiles and pterosaurs, and obscurity for turtles and lizards, and wild success for plesiosaurs, theropods, and eutherian mammals. The result is a diversity of mostly hairless, ectothermic predatory mammals lurking in swamps and scuttling up walls. Small, semi-terrestrial pliosaurs bask on logs, and maniraptors…just keep on manirapping, you know? Those fingers are pretty big, though. That sure is something.