We don't have these arguments about bipeds because we never assumed that all bipeds shared an exclusive bipedal common ancestor. I think the best alternative i

We don't have these arguments about bipeds because we never assumed that all bipeds shared an exclusive bipedal common ancestor. I think the best alternative is to use different names depending on what we're highlighting (cladistics versus functionalism, for instance). The -id/-ine suffix (e.g. ursid / ursine) seems to do this. It would be clarifying to distinguish hodgepodge groupings such as "fish", and groupings such as "ducks" that are basically monophyletic with some exceptions removed from the group. Ducks are just small Anatidae.