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Re: More on Birds, dinosaurs, and digits
At 11:02 PM 11/30/97 -0600, Toby White wrote:
>... The other lines of proof include: (1) Digit V has a
>fairly unique ontogeny in that it is not part of the digital arch.
> It forms directly at the base of IV.
I do not see that this is any better than the primary axis argument. As
far as I can see, extreme reduction would tend to leave a vestigial, or
nearly vestigial, digit in *exactly* this relationship. In short, I argue
that this is also a result of the digit's reduction, and is useless for
determining *which* digit it is.
>... (2) The chicken pes clearly has five
>digits at some points in development. The pes and manus are
But not homologous. In other words, I do not see why the manus and pes
must necessarily follow similar development patterns, especially n so
derived and altered a case as the avian manus.
>suggests that the same is true for the manus. (3) the morphological
>analogues in the five-digit croc and turtle manus also suggest that
>IV is the correct identification.
Having looked at their figures, I do not see this. As far as I can see,
and sequence that reduces digits in a way that leaves only three will
result in about the same final pattern.
In short, I saw nothing whatsoever in their article that I felt was a
convincing demonstration of the identity of the avian manual digits.
May the peace of God be with you. firstname.lastname@example.org