Board Thread:Off Topic/@comment-25396609-20150910235150/@comment-24891101-20151005192504

Phantom: You say "most often". Surely you mean always? Because the development of the notochord and then the spine was a pretty big fucking deal evolutionarily. Not a thing a lower clade can be split on in subtaxa. They'd be a different clade entirely, on another MRCA branch.