Matsuo Shin File 1: On the Subject of Martian Civilization
There have been at least three major civilizations on the planet: The Ice Warriors (sometimes known as Native Martians or Reptile Martians), the Selano descendants (Selene Martians) and the Barsoomian Remniants.
Ice Warriors occupied the planet from it's earliest phases, eventually dying out due to ecological as well as political collapse..some migrating off world, some hibernating in vast hives or vaults. by the time the Selanos arrived, there was little beyond the ruins of their technology and structures to show their presence
The Selanos adapted themselves to the environment as well as adapting their own culture in time. There have been some (most notably the historian Phenix) who suggested that they built their own identity upon earlier lost cultures that they discovered upon arrival (which in this age could be construed to be the Ice Warriors and/or Osiraian legends
After the fall, at least from best guesses, some small remnants of the Selano martians survived, most likely from the rural areas and perhaps through the help of empty ice warrior vaults. These groups eventually re-organized themselves into a clannish-almost feudal society, existing along other species (perhaps descendants of ice warriors). These beings would settle upon a new name for themselves "Barsoomians". Surpisenly, this society would last for quite a time, dying out fully sometime around Earth's 3rd century."