This is the sort of information that makes science so interesting. One set of data, along with some simplifying assumptions, indicates that the last common ancestor of all mammals existed over 100 million years ago, rather than 65 millon, as currently believed. This happens to coincide with the breakup of Gondwanaland. It may also explain why the marsupials generally originated in the Southern Hemisphere. It will be intersting to see where this line of research leads.  4:26:07 PM