Maybe an even better point. Those monotremes are in the mammal group but their line branched off on its own way back there.
What we're doing is learning more about the early history of the coelurosaur taxon. More data points should help to tell a more coherent story.
The monotremes are an excellent thing to mention in discussions of mammalian evolution. Australia got isolated at the perfect time to evolve a whole series of wierd mammals, unlike those anywhere else on the planet.
Marsupials, monotremes, and others. The Opossum is about the only marsupial anywhere outside of Australia. No monotremes exist except in Australia and the surrounding islands.
It's a perfect study of mammalian evolution. Every type of animal, from big herbivores to carnivorous predators evolved there, and in a unique way. The isolation is what did it.
It's inexplicable, except through evolution.