Geological / environmental event
The first felids emerge on Frith, including the earliest ancestors of the Frithitt.
Although dinosaurs continue to dominate most large land animal niches as the Cenozoic proceeds, a number of new mammal groups, mostly small and cryptic, continue to emerge. Among these are the felids. Though rare in modern times on Frith, except for Frithitt themselves, felids were originally a far more diverse group.