> A few weeks back I picked up a nice book (The Shapes of Time, by Ken
McNamara) that discusses heterochrony and the evolution of certain body
shapes. There was a short passage discussing the evolution and loss of
digits. McNamara and his colleagues Emily Gale and Peter Alberch tried to
correlate the relationship between digit number and body size in certain
mammals (especially dogs), finding that in larger dog breeds more digits
were often present.
This is great,
No. Giraffes have only 2 digits per limb and no trace of others. Some
elephants (forgot which ones) have lost finger V. *Tyrannosaurus* is the
biggest tyrannosauroid and has retained least of mcIII (AFAIK). And so on.
It may be correlated in dogs, but not everywhere else.