Honest answer, no one knows. My best guess is that Canis in NA is somewhat of a ring species with lupus in the NW, lyacon in the NE, rufus in the SE, and latrans in the SW.
There are taxa, such as the Herring Gull and its relations, that stretch the traditional definition of a species to the absolute limit. Whatever the Red Wolf is (or was?), it seems to be another one.
About fifteen (probably more) years ago the taxonomy of red wolves was discussed at one of the Zoological Society of London Scientific Meetings; I recall one of the speakers stating that the red wolf was not a distinct species but a naturally occurring hybrid between grey wolf and coyote.
However, according to the “Handbook of Mammals of the World” (Volume 1 Carnivores)(2009), recent evidence suggests that it is a distinct taxon and not a grey wolf x coyote hybrid.
That is the most recent book that I have that discusses this species, but even that volume is now three years old and opinions may well have changed for all I know.
