Sorry, that was shorthand. They are a mutation *pauses to muffle up the wailing of her science-brain* of the species that landed and the surface-strain of whom refer to themselves as human and have all the physiological marks of a biology that functions a whole lot like, well, humans. They are also capable of interbreeding with Haixing-humans, which, actually now I think about it, means they /are/ still human, though I suppose there's the outstanding question of whether cross-breeds are fertile or not.

*hauls herself out of the rabbit-hole* Anyway! Insofar as the surface-strain is referred to as human, Dixingren used to be human.