Theory: the Romulans are actually descended from Vulcan augments

Well on enterprise, had a hint that the schism was during surack time because he said under the rapture wing..
Telepathy is genetics, so a few options are available as to why vulcans do and romulan don't.
1. The ones with the strong genetic traits didn't leave in the exodus. So there has never been a strong enough telepath breed on romulas.maybe something like a religious caste
2. Augmentation, again, the telepathy augments stayed.
3. Mutation. Geneticly were capable with one born like surak being rare. But after the nuclear wars. Radiation had an effect of more powerful telepathy being born. While romulan didn't have the radiation.
4. All vulcanoiods are capable but it takes a mental clarity and diciplne that the romulans are seldom capable of.

 

What about the Remains? They're telepathic. Are they a totally unrelated species?

 

Possibilities abound. Crossbreeding between the Romulan arrivals and either natives of the planet Romulus or then imported slaves? A bona fide imported slave species? A genuinely native Reman species? Romulans who have been engineered to better withstand the conditions on Remus?

The novels sorta go with the latter, bowing to earlier fan perceptions (and novels) of the same folks having settled both Romulus and Remus. Onscreen, we learn zip.

We might well say that Vulcans and Vulcanoids have nothing against artificial genetical improvement, and apply it extensively. Or indeed that the general species itself is highly malleable (perhaps because of engineering previously conducted on it galaxy-wide, possibly by Sargon's folks) and its assorted splinter groups readily interbreed (also with radically different aliens such as humans or Klingons) and rapidly adapt to extremes in the environment.

Or then this general flexibility was already built in by the Ancients of "The Chase" who would like nothing better than a galaxy full of madly interbreeding, diverse humanoid types. Vulcanoids retain this trait, as do Klingons. And humans are invalids of some sort, hobbled not just by their silly taboos but also by their inferior biology.

Timo Saloniemi

 

That remans to be seen.