. . . Of course, the question is which one was the subspecies. And you can't ask Bele and Lokai, because you'll never hear the end of it.
I sure as hell don't want to hear those two shouting clichés at each other for another hour!
Third Nacelle wrote:
Would Romulans be considered a subspecies of Vulcans? Or vice-versa? Remans a subspecies of Romulans?
In "Balance of Terror," Spock says he thinks it "likely" that the Romulans are "an offshoot of my Vulcan blood."
According to TMOST
The Romulans are an off-shoot of the Vulcan race, but lost contact with the Vulcans in the distant past. The two races are physically almost identical, and it is extremely difficult to tell them apart, even with sensor readings.
(Of course, "race" in Trek is used pretty much interchangeably with "species.")
I'm sure there's plenty of post-TOS canon/fanon on Romulan origins.