Early in his MKII tournament outcome, we learn Reptile is descended from a race of reptilian creatures hailing from the time of the dinosaurs. In Khameleon’s MKT tournament outcome, the term “Raptors” is used for the species, we are told they were sentient, and they fled to a realm called Zaterra when Earthrealm was nearly destroyed in a battle between the gods. In MK4 we learn the particular gods in question were Raiden and Shinnok. In MKDA the term “Raptors” is primarily used for the species but we also see the term Saurian (Reptile’s Past, The Krypt, coffin QV). Since then, the MK community has taken to using the term “Saurian” in place of “Raptor” when referring to Reptile’s species, despite the latter’s much higher frequency in the canon text. Of course the word “saurian” is a word used to describe many different species of lizards, including some who’ve gone extinct and so it is really a generalization of Reptile’s species and those related to it.
But consider the following:
It is most likely the case that life forms had already evolved on Zaterra by the time Shinnok and Raiden battled for the realm of Earth. It is also possible that these “native Zaterrans” crossbred with the Raptors during the subsequent time they cohabited the realm, which gave rise to a new species, the Saurians, which are hybrid of the original Raptor and Zaterran species. Maybe it was from their Zaterran ancestors these Saurians inherited their matriarchal structure. The native Zaterrans could also be responsible for the magic that keeps those near the matriarch in a more evolved state.
It could also be the case that the interaction between the native Zaterran species and the Raptors was not a peaceful one. It could be that the Raptors mercilessly subdued the natives driving them near to extinction, as Shao Kahn would do to them when he annexed Zaterra to Outworld. This could account for Khameleon’s MKA bio wherein she refers to the Zaterran species as “Raptors.”