What is the origin of Atlanteans?

Homo Mermanus is a 10,000 year-old offshoot of humanity whose exact origins still remain unknown. 2,000 years after the "Great Cataclysm" that sunk the continent of Atlantis, Atlantean (Homo Mermanus) society emerged among its sunken ruins. They may be s natural offshoot or the result of some form of experimental intervention No one knows.

Homo Mermanus are not Deviants, though, but I could see how the the confusion could be made. 500 years after the settlement of Atlantis, another group of  Homo Mermanus left Atlantis to found their own city – this time in a part of the ruins of another continent submerged during the Great Cataclysm – in Lemuria in the Pacific Ocean. These Atlantean cousins, who came to be known as Lemurians, settled in one section of Lemuria while another section of the ruins were retrofitted for settlement by the Deviants. However, the two races are distinct from one another.

/r/Marvel Thread