These creatures lived around 260 million years ago and survived an extinction event in the mid-Permian, but were killed with almost everything else in the great end Permian extinction. At that time Therapsids, a protomammalian group of animals was doing well, but were virtually extinguished at the end of the Permian, allowing the 150 million year rise of the dinosaurs. Of course, the dinosaurs were extinguished at the end Cretaceous extinction, allowing the timid secretive little mammals to thrive and grow into the vacant ecological niches. Who knows who will survive/thrive next. Vanity, vanity, all is vanity!!
