[b_sharp]

"The overlapping ends are in the same area, but I'd say the speciation was allopatric. It is caused by differences of adaptation and history enforced by considerable if not total geographic isolation up until the ends reunite.

Would we know that if all the intermediate subspecies were extinct.

[VadeRetro]

Don't think so. Some of this may be hard to sort out given the paucity of data points and the long time frames involved.