As a side note, it looks like Wikipedia may have pulled some of the information from the NW website since the following are all partner airlines with NW:
...
Perhaps the NW/DL merger is what's driving some of the speculation that one or more of the above airlines will become a member of Skyteam.
So now we know where the bad information came from, I guess.
Being a partner of one or two carriers in an alliance does not put an airline in line to join that alliance. By that same metric SQ is about to join ST, as they are a DL partner.