The fourth refuge

Because of their high rank at the trophic level, carnivores had very tough days during the END.
Large carnivorous animals were the first to perish with the extinction of large and medium prey and the near disappearance of the smaller ones. No antarctic predator (both flying and terrestrial) larger than 1 kg was able to pass alive through the Lentocene-Cambiocene limit...with one exception: the soulfeeder (Charoncyon nihilensis).
This fox-sized mammal is nothing less but a dwarf sheardog, the smallest and the only survivor of the biwolves' radiation.
Curiously enough, this mammal didn't survive in the Green Refuges, where terrestrial vertebrates were not enough to sustain a viable population. Instead, the coastlands of the Amery Bay worked as an unexpected refuge for this otter: by feeding on dead marine animals washed ashore and occasionally hunting crustaceans and bird eggs, the coastal soulfeeder was able to somehow survive in these conditions for thousands of years. 
Despite being a solitary hunter, large aggregations can often happen near large carrion, where most of the intersocial communication outside the breeding period occurs.
After more than 6000 years with a nearly stagnant population of 5.000 individuals, soulfeeders were able to progressively increase their range thanks to the expansion of armadrails and coalgraspers in the Green Refuges, but they will become continentally widespread only with the rise of the first giants of the Cambiocene.
With no herdstalkers and wardrums, a completely new hegemony has now been born: the sheardog hegemony.