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Re: Digit Loss
Daniel Bensen wrote:
We see numerous examples of digit-loss in tetrapod evolution, but no
digit creation. The closest instance I can think of to digit creation
(except for aberrant things like two pinkies---which don't seem to
propagate through breeding(has anyone looked into that?)) is the panda's
thumb, actually an altered set of wrist bones, that went through all
sorts of intermediate mutations before arrive at its present, functional
state. Any seeming tendency for digit-reduction is due to the fact that
more-toes mutations are much harder to achieve than less-toes mutations,
and so the less-toes mutations tend to build up over time.
What about the hyperphalangy in ichthyosaurs? And isn't the pteroid bone in
pterosaurs analogous to the panda thumb, also an altered (meta)carpal?
Raymond Thaddeus C. Ancog
Mines and Geosciences Bureau