Thanks, Yde -- I should have included the junior synonym example in my original list, so I'm glad you raised it.

Let me slightly modify your list (I've stripped the name authorships to make it less cluttered -- we assume no homonyms here -- and "ba" is the feminine form of "bus"):

1. Aus, as it appears in Smith 1995 2. Aus bus, as it appears in Smith 1995 3. Aus cus, as it appears in Smith 1995 4. Xea, as it appears in Jones 2000 5. Xea ba, as it appears in Jones 2000 6. Aus, as it appears in Pyle 2005 7. Xea, as it appears in Pyle 2005 8. Xea bus, as it appears in Pyle 2005 9. = Xea ba (Smith 1995) Jones 2000 10. = Aus bus Smith 1995 11. = Aus cus Smith 1995

The last 3 are "as they appear in Pyle 2005").

Among the three implied junior synonyms (#s 9, 10 & 11), there are several types:

- #9 is the same basionym, same combination, different epithet spelling.

- #10 is the same basionym, same epithet spelling, different combination.

- #11 is a different basionym.

I see these as three different classes of "synonyms", and I do not believe that we need to enumerate these (and other) classes of synonyms before we can implement a GUID system for taxon objects.

Applying the NameUsage instance paradigm as I have described it to this case, #s 1-7 would each get a distinct GUID. As for 8-11, because there are four distinct NameStrings within one documentation instance (Pyle 2005) -- four GUIDs would be assigned.

There are various degrees of ambiguity as to what nomenclatural and Concept links could/would/should be established among these nine GUID-represented objects (some are obvious, and some may not be obvious), but at least there is no ambiguity about what objects should have a GUID assigned to them.

Aloha, Rich