Fascinating.
So it seems the Ehlnofey had already subgradiated into the Nords by the time of the move to Atmora.

But now I have the question of why they left in the first place.
What was it about Atmora that drew them there?

The war with the elves in the Dawn Era. I think they either retreated when Shor fell or were trapped there when the land was sundered.

Returning as no different from when they left, but the elves became Falmer? What accounts for the stasis in the Nords?

But the Anuad clearly states that some Ehlnofey arrived scattered.

There was only one continent at the time, covering the globe. It wasn't until the Ehlnofey war (which started when the Wandering Ehlnofey found Old Ehlnofey, who wouldn't let them in) that land dropped into the sea to create the Tamriel/Atmora/Yokuda separation.

Throat of the World

This is the highest mountain in Skyrim, and the highest in Tamriel aside from Vvardenfell in Morrowind. The Nords believe men were formed on this mountain when the sky breathed onto the land. Hence the Song of Return refers not only to Ysgramor's return to Tamriel after the destruction of Saarthal, but to the Nords' return to what they believe was their original homeland. Pilgrims travel from across Skyrim to climb the Seven Thousand Steps to High Hrothgar, where the most ancient and honored Greybeards dwell in absolute silence in their quest to become ever more attuned to the voice of the sky.

From the First Pocket Guide.

It makes cosmic sense when you think about it.

Basically like this, if I've got my stuff straight: Nirn is created, Ehlnofey and Hist populate the land. Tamriel is like some mythical mega-continent. Ehlnofey break into Aldmer and Men. Dawn Era ends with Tamriel split across the oceans (and the Hist are said to have mostly sunk under the waters in this time of awful fighting, only remaining in the swamps of Black Marsh). Left-handed Elves and proto-Redguards end up on Yokuda. Some Men leave for Atmora, others stay in Cyrodiil (the Nedes, et al). The Aldmer, spreading out from the Summerset Isles, become Ayleids, Bosmer, Orsimer and Velothi (Chimer, later Dunmer), and those remaining in Summerset become Altmer. The Dwemer split at some unknown point in the far past.
Atmoran Men return to Tamriel, some split off and mix with Altmer in High Rock becoming the Bretons, others become the Nords.
Yokuda is destroyed, Redguards return to Tamriel.
Bosmer and Khajiit come from the same aldmeri forest-people, with Khajiit taking their distinctive form because of a blessing by Azura or somesuch. (not entirely sure on either point)

I think that's everybody.

edit: Oh, the Argonians. Produced by the Hist, the only sentient race of Tamriel that isn't descended from the Ehlnofey.
Pretty sure giants trace back to the Ehlnofey as well, actually.

There are known to other continents that have not been named or chartered. Perhaps Humans decended from one of them before splitting off to Yokuda and or Atmora?

So how is that reconcilable with the Nu-Mantia intercept that states that there was never such a place as Old Ehlnofey. Don't get me wrong, I'm not saying that statement should be taken completely at its word.

It would be impossible for there to be no original home for the Old Ehlnofey, even if that home was just the place they all first materialized. If the Old Ehlnofey never had a home, than logically they never would have existed.

Did the Ehlnofey suffer some sort of racial amnesia, causing them to forget their first years on Nirn, I wonder?

I still find it strange that Humanity could have a single point of origination, given the extremely alien quality of the Yokudan belief system in relation to the Nedic. If the two civilizations were truly a single people at one time, why do their religions differ so greatly with such a vast gulf between their languages and beliefs? It makes no sense to have a single population that branches off into two sub-races which diverge by 180 degrees the second the two gain distance from each other.

And, I doubt the Khajiit are (descended from) elves.

This explains it very well http://www.imperial-library.info/content/childrens-anuad
Btw. the Ayleids are Altmeri Elves, just another branch. They are called "The Wild Elves", they are like the "Forsworn" of the Altmer race, holding on to old believes etc.

This contrasts with the Forsworn, who have some really crazy maybe-lovecraftian-though-I-don't-know-anything-because-I-haven't-read-anything-about-the-forsworn gods. Major differences from the three big civilizations of Men that surround where they live.

I've never heard the actual phrase human in a TES game (at least I don't remember it, been playing since MW), it's always Man or Mer.

I still find it strange that Humanity could have a single point of origination, given the extremely alien quality of the Yokudan belief system in relation to the Nedic. If the two civilizations were truly a single people at one time, why do their religions differ so greatly with such a vast gulf between their languages and beliefs? It makes no sense to have a single population that branches off into two sub-races which diverge by 180 degrees the second the two gain distance from each other.

I find it strange that you think they would be more similar. Is this not what happens IRL also?

You're saying Ogres, Goblins and Dreugh are descended from Ehlnofey?

I'm 99% sure the Dreugh are not.

Ironically, there are some hints that they may indeed be Mer.

It's not *my* theory, it's the FACT agreed upon by scientists worldwide.

Pretty much just what it says. I was reading up on them and noticed that they don't share the ancient ancestral home of humans. So... what are they, if not human?