(March 12, 2015 at 12:36 pm)robvalue Wrote: Everything (likely) has a common ancestor, but that doesn't mean that every animal family family is descended from every other, or vice versa. Your aunt can't give birth to your brothers, to use a metaphor.
That's not the point, the point is, where has one animal family been observed to split off into a separate animal family? (however you wish to define it)