The issue is resolved, at least for now. My Alliance returned. I do not know where it went on its brief vacation, but I hope it had fun (even though I was home worrying about its safety).
Because I could never find an alliance I could work with, I started my own, paying the coin fee from my account stash of coins. Now, with the Easter/Bunny/Egg event going on, my alliance is gone. No message saying that is was going to be removed for whatever reason and a chance to correct any issue. Just “poof” gone.
Is this a bug? A mistake? Will it come back? Or do I have to go out into the dark and scary wilderness with my hat in hand begging someone to take in this poor homeless dino collector?