Consider recent ideas on phytosaur phylogenetic position. If you prefer the stability of definitions, phytosaurs fall outside Archosauria. But there is a clade for phytosaurs + archosaurs, that have basically the same content as was though for Archosauria before. So, for the 'other' stability, why not broaden Archosauria, with phytosaurs considered just the first offshot? While the name flips to another node, the stability of content is saved, and 'new' archosaurs, for practical purposes, remain the same group as 'old' archosaurs.Dnia 13 czerwca 2020 08:37 dawidmazurek@wp.pl <dawidmazurek@wp.pl> napisaÅ(a):
Dnia 13 czerwca 2020 06:36 TimÂ
I thought, by definition, that A and B had to be part of the clade.IMO, here lies the problem. I prefer the stability of content over the stability of definition. If I ever look at an older paper, and read that members of the clade A+B are mainly long-necked, I would need to check what taxa were at that point though to belong to A+B, as it might be that nowadays, because of the change in content, most taxa in A+B are known to be short-necked. Not a problem if you add or delete a species here or there, but if content changes much, a new name is better than a 'stable' name that can move back and forth through a tree. And if the grouping is found to be non-monophyletic, just forget the name used for it.