Re: ALIMENTARY MY DEAR HOATZIN

[Betty Cunningham <bettyc@flyinggoat.com>]

The hoatzin is not unique with the juvenile having a finger on it's
wing.  

The marsh hen, a few domestic chickens, and some ducks have been seen
with the same feature (though not as functional as I understand it).   
(One of the EYEWITNESS series of childrens' books has a photogragh of a
fingered marsh hen chick) 

If ducks and marsh hens (both of whom do not live by climbing) have such
a feature it is most likely retained from a prior ancestor who DID use
the finger (for an undefined purpose), rather than being something ducks
and marsh hen have developed in parallel to the hoatzin for climbing.

In all cases of this finger that I have heard of it is not retained as
an adult. I would be interested to know if the finger falls off or is
re-absorbed, however.  Does it have the characteristics of a skin thing
or the characteristics of a gross anatomy thing.

-Betty Cunningham

Rob Meyerson wrote:
> Are the climbing 
> adaptations in the hoatzin young a primary feature, or was it 
> secondarily derived?  IOW, is this something that evolved 
> specifically in this critter, or is it a relic from prehistoric 
> times? 

-- 
Flying Goat Graphics
http://www.flyinggoat.com
(Society of Vertebrate Paleontology member)
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