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Re: One for the bird brigade



--Original Message-- From: Thomas R. Holtz, Jr. <th81@umail.umd.edu>:
Friday, December 18, 1998 06:19 PM

>>But you can tell the person who asked you the
>>question, 'the hoatzin'.  It should keep them happy, and will do them no
>>harm!

[I should have put a  ;-)  here, I think!]

>
>Except to perpetuate the idea that hoatzins are primitive birds, rather
than
>the highly specialized critters they are!

And yet another of their specialisations which one tree I saw suggests, is
that they are very cosy with the birds of prey.  Maybe they may have been
birds of prey once themselves (I mean proper tertiary birds of prey).  As
one of the very few birds that specialise in eating leaves, I wonder if they
share the ability to scissor through a bit of leaf in the way some bird of
prey's bills can scissor meat?

Randy King said:

>I don't agree.  I suppose it may depend on your definition of closest
>though.  I presume the question really is looking for the least diverged
>from Archie.  And given different mutation rates and even different
>genaration lenghts, I would claim that all birds are not equally related
>to Archie.

Interesting ;  each generation brings a new oportunity for mutations and
mixing, so it is tempting to consider whether a line with an average of a
couple of years per generation would be 'further' from the ancestor after
say 100 million years than one with 5 years per generation.  Of course in
five years there is more time for mutations to occur, so perhaps it doesn't
mean much.

Maybe if we could find a bird type that has for some reason had fewer
mutations down the line, it really might be considered closer to Ax.
Unfortunately degreee of molecular mutation often bears little direct
relation to morphology (physical form).  The deinonych.s of the very early K
were much more closely related to Ax than to late K deinonych.s.


JJ