Alternative histories and parallel universes

Matt Pearson wrote:

> It was along this network that horses, cows, and various kinds
> of plants were first introduced to the New World.
"First" in historic times, that is.  The lineage of fossil horses
over the last 65 million years was first reconstructed in Europe,
with four clear stages including the modern one.  It turns out,
however, that this does not represent a line of descent, but rather
four migrations from the New World, where horses form a moderately
diverse evolutionary bush of which only the one genus *Equus*,
seven species, survive.

What are the seven, you ask?

        E. caballus, the common horse;
        E. przewalski, Przewalski's wild horse (extinct in the wild,
                now often considered a subspecies of E. caballus);
        E. zebra, the mountain zebra;
        E. burchelli, the common (or Burchell's) zebra;
        E. grevyi, Grevy's zebra;
        E. asinus, the common ass;
        E. hemionus, the onager or Asiatic half-ass.

--
John Cowan      http://www.ccil.org/~cowan              cowan@ccil.org
        You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
        You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
                Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)