Also I wonder if there's a move away from "mega" towards "giga" as mega anything seems kinda small. I can't see "tera" ever being a thing, I can't think of an independent connection to some other word meaning large.
It's not obvious to me how the speed of extinction would affect the number or quality of preserved skeletons.
It’s funny how they (and all the other large mammals) survived for 1.8M years of massive global climate change but the period just after we arrived (like in the Americas) was what “hastened their demise” rather than the humans with clubs they hadn’t had time to evolve to be scared of, eating every last one of them.